One-pot synthesis of functionalized benzo[c]coumarins and their precursors via the reaction of 2-(polyfluoroalkyl)chromones with 4-alkyl-3-cyanocoumarins

Abstract

2-(Polyfluoroalkyl)chromones react with 4-alkyl-3-cyanocoumarins in dichloromethane in the presence of triethylamine to give a wide variety of functionalized benzo[c]coumarin derivatives in good yields. This new annulation reaction presumably proceeds by a tandem intermolecular Michael addition and subsequent intramolecular condensation between an intermediate enolate anion and cyano group. In the case of 3-cyano-4-methylcoumarin and 2-(trifluoromethyl)chromones activated by two electron-withdrawing substituents, three acyclic intermediates were isolated and the possible mechanism of the reaction was suggested.

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Introduction

Chromones and coumarins are abundant in nature and are found in a wide range of pharmaceutically active compounds. Numerous biological activities have been attributed to simple chromones and their analogues such as anti-inflammatory, antiplatelet, anticancer, and antimicrobial activities, including those related with central nervous system and obesity.¹ Coumarin and its related analogues are found to occur naturally as secondary metabolites in higher plants and also in microorganisms. Natural as well as synthetic coumarins exhibit significant biological activities, such as anticoagulant, analgesic, antitumor, antiviral, anti-inflammatory and antioxidant effects, as well as antimicrobial and enzyme inhibition properties.²

Due to this biological importance, we envisaged that the combination of a chromone system with a coumarin ring would allow the development of a new class of biologically active molecules and useful synthetic building blocks in organic and medicinal chemistry. However, although chromones are electrophilic substrates and some coumarin derivatives such as 4-hydroxycoumarins have nucleophilic sites, their ability to react with each other has been illustrated with only few examples.³ Most pertinent to the present research is the reaction involving a basic 1,4-conjugate addition of 3-acetoacetylcoumarins⁴ on chromone-3-carboxylic acid in refluxing chloroform containing a catalytic amount of 4-pyrrolidin-1-ylpyridine (4-PPy). In this case, polyfunctionalized benzo[c]coumarins had been formed in 23–70% yields by a tandem pathway involving Michael addition, decarboxylation and aromatization (Scheme 1).⁴

Scheme 1 Synthesis of benzo[c]coumarins from 3-acetoacetylcoumarins and chromone-3-carboxylic acid.⁴

It should be noted that construction of the 6H-benzo[c]chromen-6-one (dibenzo-α-pyrone) derivatives has attracted much interest, because some of them represent specific proliferation inhibitors of endothelial cells⁵ and oestrogen receptor growth.⁶ Other benzo[c]coumarin structures have been described as potent and selective antagonists of estrogen receptor subtype β.⁷ Recently reported syntheses of this skeleton, which is present in a number of pharmacologically relevant natural products, such as autumnariol,⁸ autumnariniol,⁹ alternariol,¹⁰ and altenuisol,¹¹ rely on sequential [3 + 3]-cycloaddition–Suzuki cross-coupling reactions,¹² Me₃SiOTf-mediated condensation of 1,3-bis(silyl enol ethers) with chromones followed by domino retro-Michael–aldol–lactonization reactions,¹³ reactions of chromones with dimethyl 1,3-acetonedicarboxylate,¹⁴ ethyl cyanoacetate and diethyl malonate,¹⁵ as well as 4-chloro-3-formylcoumarin with 1,3-bis(silyl enol ethers)¹⁶ and 1,3-dicarbonyl compounds.¹⁷

On the other hand, in recent years, 2-(trifluoromethyl)chromones have attracted considerable attention as highly reactive substrates, which can serve as the starting materials in the synthesis of various partially fluorinated heterocycles.¹⁸ The enhanced reactivity of these compounds is presumably due to the powerful electron-withdrawing ability of the CF₃ group, which additionally activates the C-2 atom (it is usually attacked first) and thus facilitates the addition of nucleophilic reagents despite the steric hindrance.¹⁹ Among the diverse transformations of 2-CF₃-chromones, one of the most interesting is their base-mediated condensation with ylidenemalononitriles having both nucleo- (Me) and electrophilic (CN) groups, to give the corresponding polyfunctionalized benzophenones and xanthones.²⁰ This one-pot synthesis can be considered as a tandem intermolecular Michael addition of the activated methyl group to the double bond of the pyrone ring and subsequent intramolecular recyclization with participation of the cyano group. As a continuation of our studies on the synthetic potential of 2-(trifluoromethyl)chromones 1, we decide to investigate their reaction with 3-cyano-4-methylcoumarins 2 also having a nucleophilic methyl group and an electrophilic cyano group in the molecule (Fig. 1). Herein, we report that this condensation is a new one-pot transformation of the chromone system and can be employed to obtain a wide range of the functionalized benzo[c]coumarins bearing trifluoromethyl and amino groups. The substitution pattern present in our products is, to the best of our knowledge, not available via previously known transformations.

Fig. 1 Chromones 1 and coumarins 2 used in this study.

Results and discussion

A characteristic property of 3-cyano-4-methylcoumarins 2 is the acidity of the methyl group at C-4, which is greatly enhanced owing to the strongly electron-withdrawing groups attached to the double C=C bond. As a result, some direct vinylogous reactions of coumarins 2 might be developed by mild base-catalysis. Thus, compounds 2a–c are able to condense with aromatic aldehydes²¹ and 3-formylchromones²² under the influence of bases to give the corresponding styryl derivatives. The vinylogous Michael addition of 3-cyano-4-methylcoumarin (2a) to α,β-unsaturated ketones was also described,²³ however, its potential as a successful donor and acceptor in tandem anionic reactions was not recognized so far. Only two reports are known which describe the reaction of coumarin 2a with arylidene malononitriles and arylidene cyanoacetates to produce 7-amino-6-oxo-9-aryl-6H-benzo[c]chromene-8-carbonitriles;^21a the reaction of methylenemalononitrile with 2a afforded benzopyrano[4,3-h]quinoline.²⁴ The kinetic acidity of the methyl group in coumarins 2 led us to investigate the utility of the reaction of this methyl function for synthesizing other useful heterocyclic derivatives. 4-Methyl- and 4-ethyl-3-cyanocoumarins 2a–d (Fig. 1) were prepared by condensation of equimolecular amounts of the corresponding 2-hydroxyacetophenone or 5-bromo-2-hydroxypropiophenone with malononitrile in ethanol in the presence of 10% NaOH.²⁵

Continuing our research program dedicated to the design and synthesis of new 3,4-fused coumarins^15,26 and in view of the unique biological properties displayed by partially fluorinated compounds,²⁷ we decided to study the reactions of 4-alkyl-3-cyanocoumarins 2a–d with a set of readily available substituted 2-(polyfluoroalkyl)chromones 1a–l (Fig. 1). It is known that 2-alkylchromones are less reactive than 2-unsubstituted chromones due to steric and electronic factors, however, the introduction of electron-withdrawing R^F groups at the 2-position of the chromone system significantly changes the reactivity of the pyrone ring with respect to nucleophiles. Recently,²⁰ 2-R^F-chromones with electron-withdrawing substituents in the benzene ring have gained the wide application as substrates for the reaction with ylidenemalononitriles. Logically, they were taken as starting materials of choice.

We have started this work by the study of the reactions of less reactive 2-CF₃-chromones 1a–d and found that they react with coumarin 2a in dichloromethane in the presence of triethylamine (1 equiv.) at room temperature for 14–45 days affording benzo[c]coumarins 4a–e in low yields (except chromone 1b, which gave coumarin 4b in 63% yield). The products 4a–b could be isolated by simple filtration of the precipitate formed, while compounds 4c–d were purified by column chromatography. This reaction is an earlier unknown transformation of 2-CF₃-chromones, which can be regarded as nucleophilic 1,4-addition of a coumarin ring due to the presence of a vinylogous methyl group with the formation of a new C–C bond (intermediate A). Subsequently, γ-pyrone ring opens by cleavage of the C–O bond to form an intermediate B, which cyclizes at the cyano group to give benzo[c]coumarins 4 via intermediate salts 3. The acyclic intermediates A and B and salts 3a–d were not observed in this case, however, they were isolated during the work with more active chromones 1i–j (see below). Clearly, the electron-withdrawing CF₃ group enhances the electrophilicity of the starting chromones 1a–d and encourages conjugate addition at the initial stage, whereas electron-donating Me and MeO groups at the 6-position retard this process despite the presence of the 5-NO₂ group (Scheme 2, Table 1).

Scheme 2 Synthesis of compounds 3 and 4.

Table 1 Isolated yields of compounds 3 and 4, prepared from chromones 1a–h

Chromone 1	Coumarin 2	Salt 3 (yield/time)	Product 4 (yield/time)
a Column chromatography (SiO2/CHCl3).b Heating of the corresponding salt 3 in concentrated HCl.
1a	2a	—	4a (17%, 45 d)
1b	2a	—	4b (63%, 14 d)
1c	2a	—	4c (24%, 14 d)^a
1d	2a	—	4d (21%, 21 d)^a
1e	2a	3e (30%, 5 d)	4e (96%)^b
1f	2a	3f (64%, 10 d)	4f (92%)^b
1g	2a	3g (67%, 2 d)	4g (77%)^b
1h	2a	3h (84%, 1 d)	4h (98%)^b
1h	2b	3i (73%, 3 d)	4i (98%)^b
1h	2c	3j (84%, 3 d)	4j (97%)^b

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Similar reactions with more reactive chromones 1e–h bearing the 6-NO₂ or 8-NO₂ group or two electron-withdrawing groups proceed faster (1–10 days) and gave triethylammonium salts 3e–j, which were isolated in a pure state in 30–84% yields. These salts were rather stable due to the more acidic phenolic hydroxyl and their conversion to the corresponding benzo[c]coumarins 4e–j was effected by heating in concentrated HCl for 15 min in almost quantitative yield (Scheme 2). The progress of the reactions was monitored by TLC, and the results are summarized in Table 1. We got the best results when the reaction was conducted in the presence of triethylamine in dichloromethane; this system we previously employed to convert 2-R^F-chromones to polyfunctionalized benzophenones.²⁰

Benzo[c]coumarin 4h was obtained in 82% overall yield as stable yellow crystals and its structure was independently confirmed by X-ray diffraction analysis. According to this, the salicyloyl fragment has a planar conformation due to the intramolecular hydrogen bond O–H· ·O=C and is tilted at −74.6(3)° to the fused rings. Benzocoumarin part of the molecule is close to planar due to its aromatic character and existence of intramolecular N–H⋯O=C hydrogen bond as shown in the picture (Fig. 2).

Fig. 2 Molecular structure of benzo[c]coumarin 4h (ORTEP drawing, 50% probability level).

We next investigated the reactions of coumarins 2a–c with tri- and tetrasubstituted chromones 1i–j, for this, it was anticipated, would give additional information and evidence for the reaction pathway. Indeed, the difference in behavior between chromone derivatives 1a–h and 1i–j was remarkable and we were able to isolate the acyclic stable salts 5k–o in 36–93% yields, probably, due to their lower solubility in dichloromethane (Scheme 3, Table 2). Note that salts 5m, 5o were obtained at 3 °C for 14 days because of strong resinification of the reaction mixture at room temperature. The intermediacy of 5k–o is in accordance with the readiness with which these salts under the action of triethylamine undergo ring closure involving the methylene group to form triethylammonium salts 3k–o, which were further converted to the final products 4k–o upon heating in concentrated HCl for 15 min in 85–93% yields. Stirring of salts 5k–o in concentrated HCl at room temperature gave adducts 6k–o in 72–93% yields with E-configuration of the double bond (X-ray data, see below). In a DMSO solution compound 6k cyclizes into the initial Michael adduct 7k (yield 75%, 6 days), while a similar conversion 6l → 7l was observed in DMSO for 15 days (yield 61%). Products 7k–l contain two CH₂ functions with J = 15.0–15.2 Hz and J = 16.6–17.3 Hz, as shown by ¹H NMR spectra; this observation obviously excluded the possibility of other structure for these compounds.

Scheme 3 Synthesis of compounds 3–7.

Table 2 Isolated yields of compounds 3–7, prepared from chromones 1i–l

Chromone 1	Coumarin 2	Salt 5 (yield/time)	Product 6 (yield, %)^a	Salt 3 (yield/time)^b	Product 4 (yield, %)^c
a Stirring of the corresponding salt 5 in concentrated HCl at room temperature.b From chromones 1i–k with 2 equiv. of triethylamine.c Heating of the corresponding salt 3 in concentrated HCl.d From salt 5.e At 3 °C.f Column chromatography (SiO2/CHCl3).
1i	2a	5k (44%, 1 d)	6k (92)	3k (42%, 3 d), (50%, 3 d)^d	4k (93)
1j	2a	5l (93%, 3 h)	6l (93)	3l (48%, 2 d), (84%, 2 d)^d	4l (85)
1i	2b	5m (36%, 14 d)^e	6m (72)	3m (56%, 1 d), (47%, 2 d)^d	4m (93)
1j	2b	5n (68%, 3 h)	6n (93)	3n (83%, 4 d), (64%, 2 d)^d	4n (92)
1j	2c	5o (57%, 14 d)^e	6o (91)	3o (83%, 1 d), (94%, 2 d)^d	4o (89)
1i	2c	—	—	3p (57%, 1 d)	4p (99)
1k	2a	—	—	3q (78%, 6 d)	4q (99)
1k	2c	—	—	3r (72%, 5 d)	4r (89)
1l	2a	—	—	—	4s (30, 14 d)^f

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Salts 3k–p were also obtained directly from chromones 1i–j and coumarins 2a–c in the presence of 2 equiv. of triethylamine for 1–4 days at room temperature in 42–83% yields. In an attempt to define the scope and limitation of this reaction, the condensation of 2-(1,1,2,2-tetrafluoroethyl)chromone 1k with coumarins 2a, 2c was investigated and compounds 3q–r and 4q–r were obtained under the same conditions in high yields. The reaction of 2-C₄F₉-chromone 1l with 2a gave only benzo[c]coumarin 4s, which was isolated in 30% yield using column chromatography on silica gel (Scheme 3, Table 2). It should be also noted that the reactions between 2-methylchromone or unsubstituted chromone and coumarin 2a did not take place under the optimized reaction conditions, indicating that the strongly electron-withdrawing groups in the substrates 1 are essential for this triethylamine-mediated reaction.

The structure of triethylammonium salts 3 was unambiguously confirmed by X-ray single crystal analysis of 3n as a representative example (Fig. 3). A common structural feature of these compounds is the presence of two intramolecular hydrogen bonds between the amino group hydrogen atoms and carbonyl group with the lengths H(1A)⋯O(7) = 1.95(2) Å and H(1B)⋯O(5) = 2.32(3) Å. The benzene ring is almost perpendicular to the benzocoumarin moiety.

Fig. 3 Molecular structure of triethylammonium salt 3n (ORTEP drawing, 50% probability level).

The structure of acyclic triethylammonium salts 5 was established by X-ray crystallographic study of crystals 5k, 5l. The molecular structure of salt 5k is presented in Fig. 4, showing that coumarin and benzene rings are arranged close to each other in parallel relation with distance between planes d 3.432 Å. The same conformation was identified also in the structurally similar salt 5l (d 3.588 Å) (Fig. 5).

Fig. 4 Molecular structure of triethylammonium salt 5k (ORTEP drawing, 30% probability level).

Fig. 5 Molecular structure of triethylammonium salt 5l (ORTEP drawing, 30% probability level).

Single crystal X-ray analysis of coumarin 6l showed that its double bond has the E-configuration (Fig. 6). This conclusion can be expanded to its analogs 6k, 6m–o, since the ¹H NMR spectra of these compounds in DMSO-d₆ are very similar and characterized by the close chemical shifts of the =CH proton (δ 7.80–7.85 ppm) and the AB system of the CH₂ group in the range of δ 4.1–4.3 ppm with the coupling constants J = 17.0–18.6 Hz as a result of restricted rotation in the molecules.

Fig. 6 Molecular structure of coumarin 6l (ORTEP drawing, 50% probability level, disordering of the trifluoromethyl group is not shown).

Thus, the formation of benzocoumarins 4 from the reaction of compounds 1 and 2 is assumed to proceed via Michael type addition of the methyl function in coumarins 2 to the activated double bond of chromones 1 (adducts 7), followed by ring-opening and 1,3-H shift to give acyclic triethylammonium salts 5 (isolable in the case of tri- and tetrasubstituted chromones 1i–j). The latter undergo intramolecular cyclization between enolate anion and cyano group to give benzocoumarin salts 3, which then could be hydrolyzed into the target products 4. Although the possibility that at the initial stage cycloadduct C is formed and then via ring-opening (intermediate D) and 1,3-H shift resulted in the formation of benzocoumarins 4 could not be disregarded (this sequence is demonstrated in Scheme 4), we believe that the suggested above mechanism is more preferred since any fused intermediates were not observed.

Scheme 4 Alternative mechanism of the benzocoumarins formation.

Finally, we decided to increase the synthetic scope of this reaction by including in our investigation 6-bromo-3-cyano-4-ethylcoumarin 2d. To our delight, replacement of the methyl group by the ethyl group did not lead to the negative result in this case; instead, under the above conditions salt 3s and benzo[c]coumarins 4t–u were isolated in the reaction of chromones 1h, 1j with coumarin 2d in variable yields (Scheme 5).

Scheme 5 Products from the reaction of chromones 1h, 1j with coumarin 2d.

Conclusion

In conclusion, we have shown, for the first time, that the condensation of 2-(polyfluoroalkyl)chromones with 4-alkyl-3-cyanocoumarins in the presence of triethylamine is a straightforward and convenient route to a wide range of functionalized benzo[c]coumarin derivatives and their precursors, which were not easily available by alternative procedures. This reaction has advantages with regard to ease of operation and the ready availability of starting materials.

Experimental

General information

NMR spectra were recorded on Bruker DRX-400 (¹H – 400 MHz, ¹⁹F – 376 MHz and ¹³C – 101 MHz) and AVANCE-500 (¹H – 500 MHz, ¹⁹F – 471 MHz and ¹³C – 126 MHz) spectrometers in DMSO-d₆ and CDCl₃ with TMS and C₆F₆ as internal standards. IR spectra were recorded on a Nicolet 6700 instruments (FTIR mode, ZnSe crystal). Mass spectra were recorded on a Waters Xevo Q-ToF mass spectrometer (ESI) with Acquity UPLC system. Elemental analyses were performed at the Microanalysis Services of the Institute of Organic Synthesis, Ural Branch, Russian Academy of Sciences. All solvents used were dried and distilled per standard procedures. Melting points were determined on a Stuart SMP40 apparatus. Known 2-(polyfluoroalkyl)-chromones 1 and 4-alkyl-3-cyanocoumarines 2 were prepared by literature procedures.^25,28

6-Bromo-4-ethyl-2-oxo-2H-chromene-3-carbonitrile (2d)

Yield 65%, mp 195 °C, light beige powder; ¹H NMR (400 MHz, CDCl₃) δ = 1.43 (t, J = 7.7 Hz, 3H, Me), 3.11 (q, J = 7.7 Hz, 2H, CH₂), 7.31 (d, J = 8.8 Hz, 1H, H-8), 7.78 (dd, J = 8.8, 2.2 Hz, 1H, H-7), 7.86 (d, J = 2.2 Hz, 1H, H-5); ¹³C NMR (126 MHz, CDCl₃) δ = 13.9, 25.3, 102.5, 112.8, 118.4, 118.6, 119.7, 128.2, 137.8, 152.7, 156.1, 166.7; IR (ATR/cm⁻¹): ν = 2226, 1726, 1596, 1548, 1486, 1404, 1358; HRMS (ESI) calcd for C₁₂H₈BrNO₂ MH⁺ 277.9817, found 277.9825.

General procedures for the synthesis of salts 3

Method A. A solution of chromone 1 (1.0 mmol), coumarin 2 (1.0 mmol) and triethylamine (0.14 mL, 1.0 mmol) in dry dichloromethane (5 mL) was allowed to stand at room temperature for several days. After removal of the solvent, the resultant residue was washed with dichloromethane–hexane (3 : 1).

Method B. The same with 2 equiv. of triethylamine.

Method C. The same from salt 5.

Triethylammonium 2-(7-amino-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-4-chloro-3-nitrophenolate (3e)

Yield 0.17 g (30%, method A), mp 161–162 °C (dec.), orange powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 1.11 (t, J = 7.2 Hz, 9H, 3Me), 2.97 (q, J = 7.2 Hz, 6H, 3CH₂), 6.30 (d, J = 9.4 Hz, 1H, H-3′), 6.87 (s, 2H, NH₂), 7.04 (d, J = 9.4 Hz, 1H, H-4′), 7.38 (t, J = 7.6 Hz, 1H, H-2), 7.40 (d, J = 8.1 Hz, 1H, H-4), 7.58 (t, J = 7.7 Hz, 1H, H-3), 7.65 (s, 1H, H-10), 8.38 (d, J = 7.9 Hz, 1H, H-1); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 104.6 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 9.5, 46.1, 104.4, 105.2, 105.5 (q, ³J_C,F = 4.3 Hz), 115.4, 117.4, 117.9, 123.9 (q, ¹J_C,F = 275.7 Hz, CF₃), 124.7, 125.4, 128.6, 129.7 (q, ³J_C,F = 3.0 Hz), 130.7 (q, ²J_C,F = 30.7 Hz, C-9), 131.6, 134.4, 134.9, 149.9, 150.0, 150.9, 161.9, 171.3, 188.6; IR (ATR/cm⁻¹): ν = 3491, 3366, 2990, 1692, 1596, 1541, 1466, 1379, 1326. Anal. calcd for C₂₇H₂₅ClF₃N₃O₆: С, 55.92; Н, 4.35; N, 7.25. Found: С, 56.03; Н, 4.37; N, 7.18.

Triethylammonium 6-(7-amino-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-3-methoxy-2-nitrophenolate (3f)

Yield 0.37 g (64%, method A), mp 269–270 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 1.12 (t, J = 7.3 Hz, 9H, 3Me), 2.99 (q, J = 7.3 Hz, 6H, 3CH₂), 3.80 (s, 3H, MeO), 6.07 (d, J = 9.2 Hz, 1H, H-5′), 6.91 (s, 2H, NH₂), 7.38 (t, J = 7.6 Hz, 1H, H-2), 7.40 (d, J = 7.8 Hz, 1H, H-4), 7.57 (ddd, J = 7.8, 7.3, 1.3 Hz, 1H, H-3), 7.64 (d, J = 9.2 Hz, 1H, H-6′), 7.66 (s, 1H, H-10), 8.38 (d, J = 7.6 Hz, 1H, H-1), 9.1–9.9 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 104.5 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 8.6, 45.5, 56.0, 94.6, 103.8, 104.9 (q, ³J_C,F = 4.8 Hz), 116.9, 117.5, 120.4, 123.5 (q, ¹J_C,F = 275.6 Hz, CF₃), 124.1, 124.9, 129.5 (q, ³J_C,F = 3.3 Hz), 130.3 (q, ²J_C,F = 30.8 Hz, C-9), 131.0, 133.8, 134.3, 135.6, 149.4, 150.4, 156.6, 161.5, 164.7, 190.0; IR (ATR/cm⁻¹): ν = 3492, 3349, 2619, 2448, 1705, 1632, 1595, 1516, 1479, 1413, 1386, 1320. Anal. calcd for C₂₈H₂₈F₃N₃O₇·0.33H₂O: С, 57.83; Н, 4.97; N, 7.23. Found: С, 57.86; Н, 4.97; N, 7.24.

Triethylammonium 2-(7-amino-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-4,6-dibromophenolate (3g)

Yield 0.44 g (67%, method A), mp 130 °C (dec.), yellow prisms; ¹H NMR (400 MHz, CDCl₃) δ = 1.13 (t, J = 7.1 Hz, 9H, 3Me), 2.80 (q, J = 7.1 Hz, 6H, 3CH₂), 6.71 (s, 2H, NH₂), 7.33–7.43 (m, 3H, H-2, H-4, H-4′), 7.57 (t, J = 7.6 Hz, 1H, H-3), 7.65 (s, 1H, H-10), 7.85 (d, J = 1.9 Hz, 1H, H-6′), 8.06 (d, J = 8.0 Hz, 1H, H-1), 8.1–8.9 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, CDCl₃) δ = 102.9 (s, CF₃); ¹³C NMR (126 MHz, CDCl₃) δ = 10.9, 46.1, 106.4 (q, ³J_C,F = 4.7 Hz), 106.5, 108.9, 115.5, 117.1, 117.7, 120.5 (q, ³J_C,F = 2.0 Hz), 122.2, 122.9 (q, ¹J_C,F = 275.7 Hz, CF₃), 123.6, 125.1, 131.9, 133.5, 133.8 (q, ²J_C,F = 32.0 Hz, C-9), 138.1, 142.4, 149.4, 151.4, 160.6, 161.7, 197.9; IR (ATR/cm⁻¹): ν = 3427, 3339, 3303, 1705, 1622, 1601, 1480, 1436, 1422, 1385, 1322. Anal. calcd for C₂₇H₂₅Br₂F₃N₂O₄: С, 49.26; Н, 3.83; N, 4.26. Found: С, 49.23; Н, 3.54; N, 4.25.

Triethylammonium 2-(7-amino-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-4-nitrophenolate (3h)

Yield 0.46 g (84%, method A), mp 150 °C (dec.), yellow needles; ¹H NMR (400 MHz, CDCl₃) δ = 1.16 (t, J = 7.2 Hz, 9H, 3Me), 2.87 (q, J = 7.2 Hz, 6H, 3CH₂), 6.64 (d, J = 9.5 Hz, 1H, H-3′), 6.71 (s, 2H, NH₂), 7.34–7.41 (m, 2H, H-2, H-4), 7.55 (ddd, J = 8.1, 7.4, 1.4 Hz, 1H, H-3), 7.65 (s, 1H, H-10), 8.06 (d, J = 8.2 Hz, 1H, H-1), 8.11 (dd, J = 9.5, 3.0 Hz, 1H, H-4′), 8.26 (d, J = 3.0 Hz, 1H, H-6′), 8.9–9.7 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, CDCl₃) δ = 102.7 (s, CF₃); ¹³C NMR (126 MHz, CDCl₃) δ = 10.1, 46.0, 106.1 (q, ³J_C,F = 4.8 Hz), 106.2, 117.4, 117.6, 121.1, 123.2 (q, ¹J_C,F = 275.7 Hz, CF₃), 123.3 (br s), 123.5, 124.1, 125.0, 130.6, 131.5, 131.6, 133.3 (q, ²J_C,F = 31.6 Hz, C-9), 134.4, 137.2, 149.4, 151.3, 161.6, 175.3, 195.1; IR (ATR/cm⁻¹): ν = 3453, 3386, 3275, 2666, 2534, 1702, 1647, 1621, 1593, 1541, 1507, 1478, 1452, 1439, 1408, 1386, 1343, 1322, 1300. Anal. calcd for C₂₇H₂₆F₃N₃O₆: С, 59.45; Н, 4.80; N, 7.70. Found: С, 59.06; Н, 4.42; N, 7.72.

Triethylammonium 2-(7-amino-2-methyl-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-4-nitrophenolate (3i)

Yield 0.41 g (73%, method A), mp 269–270 °C (dec.), yellow powder; ¹H NMR (400 MHz, CDCl₃) δ = 1.17 (t, J = 7.2 Hz, 9H, 3Me), 2.50 (s, 3H, Me), 2.90 (q, J = 7.2 Hz, 6H, 3CH₂), 6.4–7.2 (br s, 1H, NH⁺), 6.71 (s, 2H, NH₂), 6.81 (d, J = 9.4 Hz, 1H, H-3′), 7.27 (d, J = 8.3 Hz, 1H, H-4), 7.36 (dd, J = 8.3, 1.2 Hz, 1H, H-3), 7.65 (s, 1H, H-10), 7.84 (br s, 1H, H-1), 8.20 (dd, J = 9.4, 2.8 Hz, 1H, H-4′), 8.24 (d, J = 2.8 Hz, 1H, H-6′); ¹⁹F NMR (376 MHz, CDCl₃) δ = 102.9 (s, CF₃); ¹³C NMR (126 MHz, CDCl₃) δ = 10.1, 21.1, 46.1, 106.2 (q, ³J_C,F = 4.6 Hz), 106.4, 116.9, 117.3, 120.8122.4, 123.2 (q, ¹J_C,F = 275.6 Hz, CF₃), 123.4, 123.5, 130.8, 131.2, 132.6, 133.4 (q, ²J_C,F = 31.6 Hz, C-9), 134.7, 135.3, 137.6, 149.4, 162.0, 174.2, 196.0 (one C atom is not observed); IR (ATR/cm⁻¹): ν = 3445, 3341, 1690, 1592, 1549, 1495, 1430, 1306. Anal. calcd for C₂₈H₂₈F₃N₃O₆: С, 60.10; Н, 5.04; N, 7.51. Found: С, 59.89; Н, 4.85; N, 7.43.

Triethylammonium 2-(7-amino-2-chloro-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-4-nitrophenolate (3j)

Yield 0.49 g (84%, method A), mp 285–286 °C, yellow powder; ¹H NMR (400 MHz, CDCl₃) δ = 1.20 (t, J = 7.2 Hz, 9H, 3Me), 2.96 (q, J = 7.2 Hz, 6H, 3CH₂), 5.9–6.7 (br s, 1H, NH⁺), 6.72 (br s, 2H, NH₂), 6.74 (d, J = 9.5 Hz, 1H, H-3′), 7.32 (d, J = 8.8 Hz, 1H, H-4), 7.50 (dd, J = 8.8, 2.1 Hz, 1H, H-3), 7.57 (s, 1H, H-10), 8.02 (d, J = 2.1 Hz, 1H, H-1), 8.17 (dd, J = 9.5, 2.8 Hz, 1H, H-4′), 8.22 (d, J = 2.8 Hz, 1H, H-6′); ¹⁹F NMR (376 MHz, CDCl₃) δ = 102.8 (s, CF₃); ¹³C NMR (126 MHz, CDCl₃) δ = 9.4, 45.9, 106.5, 106.6 (q, ³J_C,F = 4.4 Hz), 118.5, 119.1, 119.7, 121.2, 121.9, 122.8 (q, ¹J_C,F = 275.7 Hz, CF₃), 123.4, 129.9, 130.8, 131.7, 131.9, 133.9 (q, ²J_C,F = 32.1 Hz, C-9), 137.0, 137.6, 149.4, 149.8, 161.3, 171.1, 197.7; IR (ATR/cm⁻¹): ν = 3433, 3340, 1704, 1623, 1597, 1554, 1479, 1431, 1401, 1358. Anal. calcd for C₂₇H₂₅ClF₃N₃O₆: С, 55.92; Н, 4.35; N, 7.25. Found: С, 55.70; Н, 4.28; N, 7.03.

Triethylammonium 2-(7-amino-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-4,6-dibromo-3-nitrophenolate (3k)

Yield 0.30 g (42%, method B), yield 50% (method C), mp 139–140 °C (dec.), yellow powder; ¹H NMR (500 MHz, CDCl₃) δ = 1.00 (t, J = 7.0 Hz, 9H, 3Me), 2.74 (q, J = 7.0 Hz, 6H, 3CH₂), 7.07 (br s, 2H, NH₂), 7.31–7.40 (m, 2H, H-2, H-4), 7.51 (s, 1H, H-10), 7.52 (t, J = 7.8 Hz, 1H, H-3), 7.73 (s, 1H, H-4′), 8.00 (d, J = 7.7 Hz, 1H, H-1), 11.66 (br s, 1H, NH⁺); ¹⁹F NMR (471 MHz, CDCl₃) δ = 103.2 (s, CF₃); ¹H NMR (400 MHz, DMSO-d₆) δ = 1.17 (t, J = 7.2 Hz, 9H, 3Me), 3.08 (q, J = 7.2 Hz, 6H, 3CH₂), 7.02 (s, 2H, NH₂), 7.35–7.45 (m, 2H, H-2, H-4), 7.59 (ddd, J = 7.8, 7.4, 1.0 Hz, 1H, H-3), 7.69 (s, 1H, H-10), 7.88 (s, 1H, H-4′), 8.40 (d, J = 7.7 Hz, 1H, H-1), 8.86 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 104.5 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 8.6, 45.7, 88.8, 103.8, 105.0 (q, ³J_C,F = 4.5 Hz), 114.8, 116.8, 117.5, 123.4 (q, ¹J_C,F = 275.3 Hz, CF₃), 124.0, 124.8, 125.7, 129.5 (q, ³J_C,F = 1.5 Hz), 130.0 (q, ²J_C,F = 30.7 Hz, C-9), 130.9, 134.1, 137.1, 149.2, 150.4, 151.4, 161.4, 167.3, 188.4; IR (ATR/cm⁻¹): ν = 3469, 3328, 1701, 1598, 1536, 1479, 1383. Anal. calcd for C₂₇H₂₄Br₂F₃N₃O₆·CH₂Cl₂: С, 42.67; Н, 3.32; N, 5.33. Found: С, 42.65; Н, 3.27; N, 5.38.

Triethylammonium 2-(7-amino-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-3,5-dimethyl-4,6-dinitrophenolate (3l)

Yield 0.30 g (48%, method B), yield 84% (method C), mp 177–178 °C (dec.), yellow powder; ¹H NMR (400 MHz, CDCl₃) δ = 0.97 (t, J = 7.3 Hz, 9H, 3Me), 2.16 (s, 3H, Me), 2.29 (s, 3H, Me), 2.74 (q, J = 7.3 Hz, 6H, 3CH₂), 7.35 (dd, J = 8.1, 1.1 Hz, 1H, H-4), 7.36 (ddd, J = 8.0, 7.4, 1.1 Hz, 1H, H-2), 7.48 (br s, 2H, NH₂), 7.50 (s, 1H, H-10), 7.53 (ddd, J = 8.1, 7.4, 1.4 Hz, 1H, H-3), 8.02 (d, J = 8.0, 1.4 Hz, 1H, H-1), 11.10 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, CDCl₃) δ = 103.6 (s, CF₃); ¹³C NMR (126 MHz, CDCl₃) δ = 8.1, 14.1, 15.9, 45.0, 105.3, 105.5 (q, ³J_C,F = 5.6 Hz), 117.4, 117.5, 123.2 (q, ¹J_C,F = 275.9 Hz, CF₃), 123.4, 125.1, 126.7, 127.6, 128.8, 131.5, 132.6 (q, ²J_C,F = 31.5 Hz, C-9), 135.9, 136.3, 138.5, 143.6, 151.1, 151.6, 162.2, 163.4, 196.2; ¹³C NMR (126 MHz, DMSO-d₆) δ = 8.6, 13.5, 16.5, 45.7, 103.7, 104.3 (q, ³J_C,F = 5.0 Hz), 116.8, 117.5, 123.6 (q, ¹J_C,F = 275.5 Hz, CF₃), 124.1, 124.8, 125.2, 126.2, 129.0 (q, ²J_C,F = 30.7 Hz, C-9), 130.0 (q, ³J_C,F = 1.5 Hz), 130.9, 134.1, 134.5, 137.0, 145.7, 150.4, 161.6, 165.7, 193.8 (one C atom is not observed); IR (ATR/cm⁻¹): ν = 3477, 3345, 2981, 2610, 2497, 1705, 1641, 1575, 1543, 1502, 1478, 1401, 1322. Anal. calcd for C₂₉H₂₉F₃N₄O₈: С, 56.31; Н, 4.73; N, 9.06. Found: С, 56.27; Н, 4.71; N, 9.07.

Triethylammonium 2-(7-amino-2-methyl-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-4,6-dibromo-3-nitrophenolate (3m)

Yield 0.40 g (56%, method B), yield 47% (method C), mp 269–270 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 1.16 (t, J = 7.1 Hz, 9H, 3Me), 2.43 (s, 3H, Me), 3.07 (q, J = 7.1 Hz, 6H, 3CH₂), 6.80 (br s, 2H, NH₂), 7.28 (d, J = 8.4 Hz, 1H, H-4), 7.37 (d, J = 8.4 Hz, 1H, H-3), 7.64 (s, 1H, H-10), 7.66 (s, 1H, H-4′), 8.20 (s, 1H, H-1), 8.89 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 104.6 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 8.6, 20.3, 45.7, 88.8, 103.7, 105.0 (q, ³J_C,F = 4.5 Hz), 114.7, 116.5, 117.0, 123.4 (q, ¹J_C,F = 275.7 Hz, CF₃), 123.7, 125.6, 129.3 (q, ³J_C,F = 3.1 Hz), 130.0 (q, ²J_C,F = 30.7 Hz, C-9), 131.7, 134.1, 134.2, 137.1, 148.4, 149.1, 151.3, 161.5, 167.3, 188.5; IR (ATR/cm⁻¹): ν = 3478, 3345, 2678, 2634, 1733, 1692, 1632, 1602, 1559, 1536, 1488, 1470, 1402, 1376, 1355, 1346, 1329. Anal. calcd for C₂₈H₂₆Br₂F₃N₃O₆: С, 46.88; Н, 3.65; N, 5.86. Found: С, 46.71; Н, 3.85; N, 5.84.

Triethylammonium 2-(7-amino-2-methyl-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-3,5-dimethyl-4,6-dinitrophenolate (3n)

Yield 0.53 g (83%, method B), yield 64% (method C), mp 190–195 °C (dec.), orange powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 1.16 (t, J = 7.2 Hz, 9H, 3Me), 1.96 (s, 3H, Me), 2.28 (s, 3H, Me), 2.42 (s, 3H, Me), 3.08 (q, J = 7.2 Hz, 6H, 3CH₂), 7.12 (br s, 2H, NH₂), 7.27 (d, J = 8.4 Hz, 1H, H-4), 7.37 (dd, J = 8.4, 1.6 Hz, 1H, H-3), 7.57 (s, 1H, H-10), 8.17 (br s, 1H, H-1), 8.88 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 105.1 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 8.5, 13.5, 16.6, 20.3, 45.7, 103.7, 104.3 (q, ³J_C,F = 4.9 Hz), 116.5, 117.0, 123.6 (q, ¹J_C,F = 275.3 Hz, CF₃), 123.8, 125.3, 126.2, 129.0 (q, ²J_C,F = 30.6 Hz, C-9), 129.7, 131.7, 134.1, 134.2, 134.4, 137.0, 145.7, 148.4, 150.3, 161.7, 165.6, 193.8; IR (ATR/cm⁻¹): ν = 3448, 3335, 2979, 2606, 2483, 1689, 1583, 1543, 1495, 1399, 1322. Anal. calcd for C₃₀H₃₁F₃N₄O₈: С, 56.96; Н, 4.94; N, 8.86. Found: С, 57.04; Н, 4.95; N, 8.83.

Triethylammonium 2-(7-amino-2-chloro-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-3,5-dimethyl-4,6-dinitrophenolate (3o)

Yield 0.54 g (83%, method B), yield 94% (method C), mp 175–177 °C (dec.), orange powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 1.16 (t, J = 7.3 Hz, 9H, 3Me), 1.96 (s, 3H, Me), 2.30 (s, 3H, Me), 3.08 (q, J = 7.2 Hz, 6H, 3CH₂), 7.13 (br s, 2H, NH₂), 7.42 (d, J = 8.8 Hz, 1H, H-4), 7.58 (dd, J = 8.8, 2.3 Hz, 1H, H-3), 7.69 (s, 1H, H-10), 8.53 (d, J = 2.3 Hz, 1H, H-1), 8.85 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 105.1 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 8.5, 13.5, 16.5, 45.7, 103.5, 105.2 (q, ³J_C,F = 4.9 Hz), 118.7, 119.3, 123.5 (q, ¹J_C,F = 275.7 Hz, CF₃), 123.7, 125.0, 126.2, 129.0 (q, ²J_C,F = 30.9 Hz, C-9), 129.1, 130.5, 130.9 (q, ³J_C,F = 1.1 Hz), 132.9, 134.6, 137.0, 145.7, 149.0, 150.3, 161.2, 165.7, 193.6; IR (ATR/cm⁻¹): ν = 3482, 3350, 2620, 2457, 1710, 1648, 1581, 1543, 1502, 1474, 1399, 1360, 1322. Anal. calcd for C₂₉H₂₈ClF₃N₄O₈: С, 53.34; Н, 4.32; N, 8.58. Found: С, 53.23; Н, 4.29; N, 8.45.

Triethylammonium 2-(7-amino-2-chloro-6-oxo-9-trifluoromethyl-6H-benzo[c]chromene-8-carbonyl)-4,6-dibromo-3-nitrophenolate (3p)

Yield 0.42 g (57%, method A), mp 264–265 °C (dec.), yellow powder; ¹H NMR (400 MHz, CDCl₃) δ = 1.02 (t, J = 7.3 Hz, 9H, 3Me), 2.75 (q, J = 7.3 Hz, 6H, 3CH₂), 7.09 (br s, 2H, NH₂), 7.29 (d, J = 8.8 Hz, 1H, H-4), 7.42 (s, 1H, H-10), 7.47 (dd, J = 8.8, 2.2 Hz, 1H, H-3), 7.74 (s, 1H, H-4′), 7.95 (d, J = 2.2 Hz, 1H, H-1), 11.7 (br s, 1H, NH⁺); ¹H NMR (400 MHz, DMSO-d₆) δ = 1.16 (t, J = 7.3 Hz, 9H, 3Me), 3.08 (q, J = 7.3 Hz, 6H, 3CH₂), 6.81 (br s, 2H, NH₂), 7.43 (d, J = 8.8 Hz, 1H, H-4), 7.59 (dd, J = 8.8, 2.3 Hz, 1H, H-3), 7.67 (s, 1H, H-10), 7.77 (s, 1H, H-4′), 8.57 (d, J = 2.3 Hz, 1H, H-1), 8.86 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, CDCl₃) δ = 103.1 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 8.6, 45.7, 89.0, 103.6, 105.9 (q, ³J_C,F = 4.4 Hz), 114.7, 118.8, 119.4, 123.4 (q, ¹J_C,F = 275.5 Hz, CF₃), 123.8, 125.7, 129.2, 130.1 (q, ²J_C,F = 30.9 Hz, C-9), 130.3 (q, ³J_C,F = 2.0 Hz), 130.6, 133.0, 137.2, 149.1, 149.2, 151.3, 161.1, 167.4, 188.3; IR (ATR/cm⁻¹): ν = 3484, 3349, 2607, 2421, 1696, 1601, 1578, 1535, 1477, 1372, 1330. Anal. calcd for C₂₇H₂₃Br₂ClF₃N₃O₆: С, 43.96; Н, 3.14; N, 5.70. Found: С, 43.85; Н, 2.93; N, 5.57.

Triethylammonium 3,5-dimethyl-2,4-dinitro-6-[6-oxo-9-(1,1,2,2-tetrafluoroethyl)-6H-benzo[c]chromene-8-carbonyl]phenolate (3q)

Yield 0.51 g (78%, method B), mp 191–192 °C (dec.), yellow powder; ¹H NMR (500 MHz, CDCl₃) δ = 1.00 (t, J = 7.3 Hz, 9H, 3Me), 2.17 (s, 3H, Me), 2.31 (s, 3H, Me), 2.75 (q, J = 7.3 Hz, 6H, 3CH₂), 6.36 (tt, J = 54.0, 5.9 Hz, 1H, CF₂H), 7.18 (br s, 2H, NH₂), 7.33 (t, J = 8.2 Hz, 1H, H-2), 7.36 (d, J = 7.7 Hz, 1H, H-4), 7.48 (s, 1H, H-10), 7.52 (t, J = 7.7 Hz, 1H, H-3), 8.03 (d, J = 7.9 Hz, 1H, H-1), 10.91 (br s, 1H, NH⁺); ¹⁹F NMR (471 MHz, CDCl₃) δ 25.6 (ddt, J = 297.6, 55.6, 7.6 Hz, 1F, CFFH), 26.4 (ddt, J = 297.6, 55.6, 7.6 Hz, 1F, CFFH), 48.6 (d, J = 263.9 Hz, 1F, CFF), 50.7 (d, J = 263.9 Hz, 1F, CFF); ¹³C NMR (126 MHz, CDCl₃) δ = 8.0, 13.9, 16.2, 45.1, 104.9, 107.4 (t, ³J_C,F = 8.9 Hz), 111.0 (tt, ¹J_C,F = 235.5, ²J_C,F = 32.9 Hz, CF₂), 115.9 (tt, ¹J_C,F = 253.4, ²J_C,F = 25.9 Hz, CF₂), 117.4, 117.5, 123.4, 125.0, 127.0, 127.9, 128.5, 131.3, 134.7 (t, ²J_C,F = 22.5 Hz, C-9), 135.7, 135.9, 139.0, 143.9, 150.4, 151.2, 162.1, 163.1, 195.5; ¹H NMR (400 MHz, DMSO-d₆) δ = 1.17 (t, J = 7.2 Hz, 9H, 3Me), 1.96 (s, 3H, Me), 2.31 (s, 3H, Me), 3.09 (q, J = 7.2 Hz, 6H, 3CH₂), 6.54 (tt, J = 52.8, 5.9 Hz, 1H, CF₂H), 6.99 (br s, 2H, NH₂), 7.35–7.41 (m, 2H, H-2, H-4), 7.43 (s, 1H, H-10), 7.56 (ddd, J = 8.3, 7.3, 1.0 Hz, 1H, H-3), 8.28 (dd, J = 8.6, 1.2 Hz, 1H, H-1), 8.88 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 25.7 (dd, J = 272.4, 52.8 Hz, 1F, CFFH), 26.3 (dd, J = 272.4, 52.8 Hz, 1F, CFFH), 49.7 (d, J = 257.1 Hz, 1F, CFF), 51.4 (d, J = 257.1 Hz, 1F, CFF); IR (ATR/cm⁻¹): ν = 3496, 3348, 2644, 2489, 1698, 1641, 1595, 1581, 1520, 1496, 1460, 1362, 1318. Anal. calcd for C₃₀H₃₁F₄N₄O₈: С, 55.30; Н, 4.80; N, 8.60. Found: С, 55.08; Н, 4.41; N, 8.49.

Triethylammonium 2-[7-amino-2-chloro-6-oxo-9-(1,1,2,2-tetrafluoroethyl)-6H-benzo[c]chromene-8-carbonyl]-3,5-dimethyl-4,6-dinitrophenolate (3r)

Yield 0.94 g (72%, method B), mp 150–151 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 1.17 (t, J = 7.3 Hz, 9H, 3Me), 1.96 (s, 3H, Me), 2.33 (s, 3H, Me), 3.04–3.16 (m, 6H, 3CH₂), 6.59 (tt, J = 52.4, 5.5 Hz, 1H, CF₂H), 7.00 (br s, 2H, NH₂), 7.42 (d, J = 8.8 Hz, 1H, H-4), 7.51 (s, 1H, H-10), 7.58 (dd, J = 8.8, 2.1 Hz, 1H, H-3), 8.45 (d, J = 2.1 Hz, 1H, H-1), 8.84 (br s, 1H, NH⁺); IR (ATR/cm⁻¹): ν = 3485, 3473, 2663, 2485, 1702, 1635, 1584, 1523, 1478, 1397, 1316. Anal. calcd for C₃₀H₃₀ClF₄N₄O₈: С, 52.52; Н, 4.41; N, 8.17. Found: С, 52.32; Н, 4.01; N, 8.03.

Triethylammonium 2-[7-amino-2-bromo-10-methyl-6-oxo-9-(trifluoromethyl)-6H-benzo[c]chromene-8-carbonyl]-3,5-dimethyl-4,6-dinitrophenolate (3s)

Yield 0.24 g (34%, method A, 15 days), mp 144–145 °C, yellow powder; ¹H NMR (500 MHz, CDCl₃) δ = 0.97 (t, J = 7.3 Hz, 9H, 3Me), 2.16 (s, 3H, Me), 2.36 (s, 3H, Me), 2.69 (s, 3H, Me), 2.71 (q, J = 7.3 Hz, 6H, 3CH₂), 6.93 (s, 2H, NH₂), 7.23 (d, J = 8.7 Hz, 1H, H-4), 7.57 (dd, J = 8.7, 2.1 Hz, 1H, H-3), 8.15 (d, J = 2.1 Hz, 1H, H-1); ¹⁹F NMR (376 MHz, CDCl₃) δ 107.5 (s, CF₃); IR (ATR/cm⁻¹): ν = 3448, 3349, 1710, 1611, 1596, 1532, 1476, 1435, 1361; HRMS (ESI) calcd for C₃₀H₃₀BrF₃N₄O₈ [M − Et₃N + H]⁺ 610.0073, found 610.0094.

General procedures for the synthesis of compounds 4

Method D. A suspension of salt 3 (1.0 mmol) in concentrated HCl (8 mL) was stirred at heating for 15 min. After cooling, the resultant precipitate was filtered and washed with water (5 × 5 mL).

Method E. A solution of chromone 1 (1.0 mmol), coumarin 2 (1.0 mmol) and triethylamine (0.14 mL, 1.0 mmol) in dry dichloromethane (5 mL) was allowed to stand at room temperature for several days. After removal of the solvent, the resultant oils were purified by silica gel column chromatography following by recrystallization from dichloromethane–hexane (3 : 1).

7-Amino-8-(2-hydroxybenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4a)

Yield 68 mg (17%, method A), mp 253–254 °C, yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 6.92 (ddd, J = 7.9, 7.2, 1.0 Hz, 1H, H-5′), 7.03 (dd, J = 8.3, 1.0 Hz, 1H, H-3′), 7.40–7.54 (m, 5H, H-2, H-4, H-6′, NH₂), 7.60 (ddd, J = 8.3, 7.2, 1.7 Hz, 1H, H-4′), 7.64 (ddd, J = 8.2, 7.2, 1.4 Hz, 1H, H-3), 7.85 (s, 1H, H-10), 8.48 (dd, J = 8.1, 1.4 Hz, 1H, H-1), 11.36 (br s, 1H, OH); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 104.8 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 105.2 (q, ³J_C,F = 4.6 Hz), 105.3, 116.9, 117.1, 117.8, 119.5, 120.7, 121.6, 123.1 (q, ¹J_C,F = 275.5 Hz, CF₃), 124.6, 124.9, 131.7, 131.8 (q, ²J_C,F = 31.4 Hz, C-9), 132.1, 137.2, 137.3, 149.3, 150.7, 161.2, 161.5, 198.0; IR (ATR/cm⁻¹): ν = 3432, 3334, 3305, 1701, 1602, 1557, 1481, 1445, 1413, 1386, 1351, 1321, 1304. HRMS (ESI) calcd for C₂₁H₁₂F₃NO₄ MH⁺ 400.0797, found 400.0801.

7-Amino-8-(5-chloro-2-hydroxybenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4b)

Yield 0.27 g (63%, method A), mp 255–256 °C, light yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 7.02 (d, J = 8.8 Hz, 1H, H-3′), 7.39–7.50 (m, 4H, H-2, H-4, NH₂), 7.56 (d, J = 2.5 Hz, 1H, H-6′), 7.60 (dd, J = 8.8, 2.5 Hz, 1H, H-4′), 7.63 (ddd, J = 8.2, 7.3, 1.2 Hz, 1H, H-3), 7.83 (s, 1H, H-10), 8.46 (d, J = 8.2 Hz, 1H, H-1), 11.17 (br s, 1H, OH); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 104.8 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 105.2 (q, ³J_C,F = 4.6 Hz), 105.3, 116.9, 117.1, 119.9, 122.6, 122.9, 123.1 (q, ¹J_C,F = 275.6 Hz, CF₃), 124.5, 124.9, 130.3, 131.6, 131.7 (q, ²J_C,F = 31.2 Hz, C-9), 136.4, 137.1, 149.3, 150.7, 159.4, 161.3, 195.2 (one C atom is not observed); IR (ATR/cm⁻¹): ν = 3445, 3337, 3072, 1711, 1601, 1469, 1412, 1385, 1320. Anal. calcd for C₂₁H₁₁ClF₃NO₄: С, 58.15; Н, 2.56; N, 3.23. Found: С, 58.05; Н, 2.72; N, 3.37.

7-Amino-8-(6-hydroxy-3-methyl-2-nitrobenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4c)

Yield 0.11 g (24%, method E), mp 256–257 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 2.17 (s, 3H, Me), 6.98 (d, J = 8.6 Hz, 1H, H-3′), 7.26 (br s, 2H, NH₂), 7.42 (ddd, J = 8.2, 7.2, 1.0 Hz, 1H, H-2), 7.43 (d, J = 8.2 Hz, 1H, H-4), 7.54 (br d, J = 8.6 Hz, 1H, H-4′), 7.63 (ddd, J = 8.4, 7.2, 1.2 Hz, 1H, H-3), 7.79 (s, 1H, H-10), 8.45 (d, J = 8.2 Hz, 1H, H-1), 11.13 (s, 1H, OH); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 105.2 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 15.5, 105.1, 105.4 (q, ³J_C,F = 4.5 Hz), 116.2, 116.9, 117.0, 119.9, 120.3, 123.1 (q, ¹J_C,F = 275.5 Hz, CF₃), 124.5, 124.8 (q, ³J_C,F = 1.5 Hz), 124.9, 131.7 (q, ²J_C,F = 31.4 Hz, C-9), 131.7, 136.9, 137.8, 149.4, 150.2, 150.7, 157.4, 161.1, 190.3; IR (ATR/cm⁻¹): ν = 3459, 3330, 1694, 1635, 1602, 1536, 1492, 1477, 1414, 1385, 1351, 1315. Anal. calcd for C₂₂H₁₃F₃N₂O₃: С, 57.65; Н, 2.86; N, 6.11. Found: С, 57.38; Н, 2.90; N, 6.10.

7-Amino-8-(6-hydroxy-3-methoxy-2-nitrobenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4d)

Yield 0.10 g (21%, method E), mp 290–291 °C (dec.), yellow powder; ¹H NMR (400 MHz, CDCl₃) δ = 3.84 (s, 3H, MeO), 7.02 (s, 2H, NH₂), 7.25 (d, 1H, J = 9.5 Hz, H-3′), 7.34 (d, J = 9.5 Hz, 1H, H-4′), 7.36–7.41 (m, 2H, H-2, H-4), 7.53 (s, 1H, H-10), 7.58 (ddd, J = 8.2, 7.3, 1.2 Hz, 1H, H-3), 8.04 (dd, J = 8.3, 1.2 Hz, 1H, H-1), 10.81 (s, 1H, OH); ¹H NMR (500 MHz, DMSO-d₆) δ = 3.84 (s, 3H, MeO), 7.02 (d, 1H, J = 9.5 Hz, H-3′), 7.27 (s, 2H, NH₂), 7.39–7.45 (m, 2H, H-2, H-4), 7.55 (d, J = 9.5 Hz, 1H, H-4′), 7.63 (ddd, J = 8.3, 7.3, 1.3 Hz, 1H, H-3), 7.78 (s, 1H, H-10), 8.45 (d, J = 7.9 Hz, 1H, H-1), 10.78 (s, 1H, OH); ¹⁹F NMR (376 MHz, CDCl₃) δ = 103.3 (s, CF₃); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 105.1 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 57.3, 105.0, 105.3 (q, ³J_C,F = 5.0 Hz), 116.2, 116.9, 117.0, 120.4, 121.9, 123.0 (q, ¹J_C,F = 276.2 Hz, CF₃), 124.5, 124.7, 124.9, 131.6 (q, ²J_C,F = 31.3 Hz, C-9), 131.7, 136.9, 139.4, 143.4, 149.5, 150.6, 152.6, 161.1, 190.1; IR (ATR/cm⁻¹): ν = 3479, 3333, 1707, 1594, 1531, 1476, 1441, 1363, 1323. Anal. calcd for C₂₂H₁₃F₃N₂O₇: С, 55.71; Н, 2.76; N, 5.91. Found: С, 56.06; Н, 2.79; N, 5.90.

7-Amino-8-(3-chloro-6-hydroxy-2-nitrobenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4e)

Yield 0.46 g (96%, method D), mp 261–262 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 7.09 (d, 1H, J = 9.1 Hz, H-3′), 7.33–7.48 (m, 4H, H-2, H-4, NH₂), 7.63 (t, J = 7.7 Hz, 1H, H-3), 7.78 (s, 1H, H-10), 7.81 (d, J = 9.1 Hz, 1H, H-4′), 8.45 (d, J = 7.9 Hz, 1H, H-1), 11.74 (s, 1H, OH); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 105.1 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 105.0, 105.1 (q, ³J_C,F = 4.8 Hz), 114.7, 116.9, 117.0, 117.5 (q, ³J_C,F = 5.0 Hz), 121.2, 123.0 (q, ¹J_C,F = 275.4 Hz, CF₃), 124.3 (q, ³J_C,F = 1.5 Hz), 124.6, 125.0, 131.2 (q, ²J_C,F = 31.2 Hz, C-9), 131.8, 136.2, 137.0, 148.3, 149.7, 150.7, 158.5, 161.2, 189.3; IR (ATR/cm⁻¹): ν = 3471, 3335, 1696, 1644, 1605, 1548, 1480, 1419, 1361, 1318. Anal. calcd for C₂₁H₁₀ClF₃N₂O₆: С, 52.68; Н, 2.11; N, 5.85. Found: С, 52.76; Н, 2.35; N, 5.97.

7-Amino-8-(6-hydroxy-4-methoxy-3-nitrobenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4f)

Yield 0.44 g (92%, method D), mp 273–274 °C (dec.), yellow powder; ¹H NMR (500 MHz, DMSO-d₆) δ = 3.99 (s, 3H, MeO), 6.85 (d, J = 9.2 Hz, 1H, H-5′), 7.44 (t, J = 7.8 Hz, 1H, H-2), 7.45 (dd, J = 8.4, 1.0 Hz, 1H, H-4), 7.59 (d, J = 9.2 Hz, 1H, H-6′), 7.63–7.69 (m, 3H, H-3, NH₂), 7.89 (s, 1H, H-10), 8.50 (dd, J = 8.4, 1.2 Hz, 1H, H-1), 12.25 (s, 1H, OH); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 104.9 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 57.5, 104.5, 105.3 (q, ³J_C,F = 4.9 Hz), 105.7, 115.2, 116.9, 117.0, 119.3 (q, ³J_C,F = 3.7 Hz), 123.0 (q, ¹J_C,F = 275.9 Hz, CF₃), 124.7, 125.0, 130.2, 132.0, 132.3 (q, ²J_C,F = 31.2 Hz, C-9), 136.1, 138.0, 149.5, 150.8, 154.6, 156.8, 161.2, 197.5; IR (ATR/cm⁻¹): ν = 3425, 3338, 3302, 1694, 1603, 1537, 1506, 1482, 1416, 1384, 1322. Anal. calcd for C₂₂H₁₃F₃N₂O₇: С, 55.71; Н, 2.76; N, 5.91. Found: С, 55.55; Н, 2.87; N, 5.91.

7-Amino-8-(3,5-dibromo-2-hydroxybenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4g)

Yield 0.43 g (77%, method E), mp 230–231 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 7.41–7.46 (m, 2H, H-2, H-4), 7.56 (d, J = 2.3 Hz, 1H, H-6′), 7.62–7.68 (m, 3H, H-3, NH₂), 7.88 (s, 1H, H-10), 8.21 (d, J = 2.3 Hz, 1H, H-4′), 8.49 (d, J = 8.1 Hz, 1H, H-1), 12.12 (s, 1H, OH); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 102.9 (s, CF₃); ¹³C NMR (101 MHz, DMSO-d₆) δ = 106.0 (q, ³J_C,F = 4.8 Hz), 106.5, 111.0, 113.3, 117.4, 117.5, 119.4, 122.9, 123.5 (q, ¹J_C,F = 275.6 Hz, CF₃), 125.1, 125.4, 132.4, 133.8 (q, ²J_C,F = 31.2 Hz, C-9), 133.9, 138.6, 142.4, 149.9, 151.3, 158.2, 161.6, 198.8; IR (ATR/cm⁻¹): ν = 3426, 3341, 3302, 1706, 1622, 1602, 1556, 1497, 1481, 1436, 1422, 1386, 1313. Anal. calcd for C₂₁H₁₀Br₂F₃NO₄: С, 45.27; Н, 1.81; N, 2.51. Found: С, 45.43; Н, 1.65; N, 2.48.

7-Amino-8-(2-hydroxy-5-nitrobenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4h)

Yield 0.44 g (98%, method D), mp 271–272 °C (dec.), yellow crystals; ¹H NMR (400 MHz, DMSO-d₆) δ = 7.11 (d, J = 9.2 Hz, 1H, H-3′), 7.39–7.51 (m, 4H, H-2, H-4, NH₂), 7.63 (ddd, J = 8.1, 7.4, 1.3 Hz, 1H, H-3), 7.84 (s, 1H, H-10), 8.38 (dd, J = 9.2, 3.0 Hz, 1H, H-4′), 8.47 (d, J = 8.1 Hz, 1H, H-1), 8.57 (d, J = 3.0 Hz, 1H, H-6′), 12.10 (br s, 1H, OH); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 104.8 (s, CF₃); ¹³C NMR (101 MHz, DMSO-d₆) δ = 105.6, 105.7 (q, ³J_C,F = 4.7 Hz), 117.4, 117.6, 119.4, 122.8, 123.7 (q, ¹J_C,F = 275.5 Hz, CF₃), 124.3, 125.0, 125.5, 128.3, 131.2, 132.1 (q, ²J_C,F = 31.2 Hz, C-9), 132.2, 137.5, 140.0, 149.9, 151.2, 161.8, 165.5, 193.4; IR (ATR/cm⁻¹): ν = 3453, 3338, 3308, 1714, 1609, 1559, 1525, 1476, 1416, 1389, 1370, 1339, 1322. Anal. calcd for C₂₁H₁₁F₃N₂O₆: С, 56.77; Н, 2.50; N, 6.30. Found: С, 56.58; Н, 2.50; N, 6.29.

7-Amino-8-(2-hydroxy-5-nitrobenzoyl)-2-methyl-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4i)

Yield 0.45 g (98%, method D), mp 276–277 °C (dec.), light yellow powder; ¹H NMR (500 MHz, DMSO-d₆) δ = 2.44 (s, 3H, Me), 7.11 (d, J = 9.1 Hz, 1H, H-3′), 7.31 (d, J = 8.4 Hz, 1H, H-4), 7.43 (dd, J = 8.4, 1.5 Hz, 1H, H-3), 7.46 (s, 2H, NH₂), 7.83 (s, 1H, H-10), 8.28 (br s, 1H, H-1), 8.37 (dd, J = 9.1, 3.0 Hz, 1H, H-4′), 8.57 (d, J = 3.0 Hz, 1H, H-6′), 12.10 (br s, 1H, OH); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 104.9 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 20.3, 105.0, 105.2 (q, ³J_C,F = 4.7 Hz), 116.6, 118.9, 122.3, 123.2 (q, ¹J_C,F = 275.4 Hz, CF₃), 123.7, 124.2, 127.8, 130.7, 131.6 (q, ²J_C,F = 31.2 Hz, C-9), 132.5, 134.4, 137.0, 139.5, 148.7, 149.4, 161.4, 165.0, 192.9 (one C atom is not observed); IR (ATR/cm⁻¹): ν = 3458, 3336, 3306, 1704, 1636, 1605, 1524, 1500, 1477, 1409, 1343, 1325. Anal. calcd for C₂₂H₁₃F₃N₂O₆: С, 57.65; Н, 2.86; N, 6.11. Found: С, 57.70; Н, 2.79; N, 5.96.

7-Amino-2-chloro-8-(2-hydroxy-5-nitrobenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4j)

Yield 0.46 g (97%, method D), mp 286–287 °C, light yellow powder; ¹H NMR (500 MHz, DMSO-d₆) δ = 7.10 (d, J = 9.2 Hz, 1H, H-3′), 7.45 (s, 2H, NH₂), 7.47 (d, J = 8.9 Hz, 1H, H-4), 7.65 (dd, J = 8.9, 2.4 Hz, 1H, H-3), 7.96 (s, 1H, H-10), 8.37 (dd, J = 9.2, 3.0 Hz, 1H, H-4′), 8.57 (d, J = 3.0 Hz, 1H, H-6′), 8.67 (d, J = 2.4 Hz, 1H, H-1), 12.11 (br s, 1H, OH); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 105.0 (s, CF₃); ¹³C NMR (101 MHz, DMSO-d₆) δ = 105.0, 106.0 (q, ³J_C,F = 4.4 Hz), 118.8, 118.9, 122.2, 123.2 (q, ¹J_C,F = 275.6 Hz, CF₃), 124.2, 124.7 (q, ³J_C,F = 4.7 Hz), 127.8, 129.4, 130.8, 131.3, 131.7 (q, ²J_C,F = 31.4 Hz, C-9), 135.9, 139.6, 149.3, 149.4, 161.0, 164.9, 192.6 (one C atom is not observed); IR (ATR/cm⁻¹): ν = 3467, 3343, 3310, 1713, 1642, 1621, 1603, 1526, 1476, 1405, 1340. Anal. calcd for C₂₁H₁₀ClF₃N₂O₆: С, 52.68; Н, 2.11; N, 5.85. Found: С, 52.46; Н, 1.90; N, 5.86.

7-Amino-8-(2-hydroxy-4,6-dimethyl-3,5-dinitrobenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4k)

Yield 0.56 g (93%, method D), mp 259–260 °C (dec.), yellow powder; ¹H NMR (500 MHz, DMSO-d₆) δ = 7.43 (ddd, J = 8.1, 7.3, 1.1 Hz, 1H, H-2), 7.44 (dd, J = 8.4, 1.1 Hz, 1H, H-4), 7.64 (ddd, J = 8.4, 7.3, 1.4 Hz, 1H, H-3), 7.78 (s, 1H, H-10), 8.37 (s, 1H, H-4′), 8.46 (dd, J = 8.1, 1.4 Hz, 1H, H-1); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 105.3 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 102.9, 105.3, 105.4 (q, ³J_C,F = 4.7 Hz), 116.9, 117.0, 117.5, 120.3, 123.0 (q, ¹J_C,F = 275.6 Hz, CF₃), 123.4, 124.7, 125.1, 131.4 (q, ²J_C,F = 31.6 Hz, C-9), 132.0, 137.4, 140.7, 149.7, 150.1, 150.8, 156.3, 161.2, 189.4; IR (ATR/cm⁻¹): ν = 3470, 3326, 3294, 1701, 1632, 1599, 1537, 1479, 1383, 1323. Anal. calcd for C₂₁H₉Br₂F₃N₂O₆: С, 41.89; Н, 1.51; N, 4.65. Found: С, 41.87; Н, 1.73; N, 4.67.

7-Amino-8-(2-hydroxy-4,6-dimethyl-3,5-dinitrobenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4l)

Yield 0.44 g (85%, method D), mp 273–274 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 2.15 (s, 3H, Me), 2.23 (s, 3H, Me), 7.42 (ddd, J = 8.1, 7.3, 1.0 Hz, 1H, H-2), 7.44 (dd, J = 8.3, 1.0 Hz, 1H, H-4), 7.64 (ddd, J = 8.3, 7.3, 1.2 Hz, 1H, H-3), 7.74 (s, 1H, H-10), 8.44 (dd, J = 8.1, 1.2 Hz, 1H, H-1); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 105.7 (s, CF₃); ¹³C NMR (101 MHz, DMSO-d₆) δ = 13.2, 15.1, 105.3 (q, ³J_C,F = 5.5 Hz), 105.6, 116.9 (2C), 122.8, 123.2 (q, ¹J_C,F = 275.6 Hz, CF₃), 124.8, 125.0, 126.6, 127.9, 131.2 (q, ²J_C,F = 30.8 Hz, C-9), 132.1, 134.1, 137.9, 140.8, 143.7, 150.8, 150.9, 152.0, 161.3, 193.0; IR (ATR/cm⁻¹): ν = 3488, 3338, 1701, 1586, 1537, 1477, 1426, 1382, 1363, 1324; HRMS (ESI) calcd for C₂₃H₁₄F₃N₃O₈ MH⁺ 518.0811, found 518.0818.

7-Amino-8-(3,5-dibromo-2-hydroxy-6-nitrobenzoyl)-2-methyl-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4m)

Yield 0.57 g (93%, method D), mp 252–253 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 2.44 (s, 3H, Me), 7.33 (d, J = 8.4 Hz, 1H, H-4), 7.38 (br s, 2H, NH₂), 7.44 (d, J = 8.4, 2.0 Hz, 1H, H-3), 7.77 (s, 1H, H-10), 8.28 (d, J = 2.0 Hz, 1H, H-1), 8.30 (s, 1H, H-4′); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 105.3 (s, CF₃); IR (ATR/cm⁻¹): ν = 3492, 3369, 1699, 1634, 1584, 1538, 1488, 1439, 1411, 1378, 1322; HRMS (ESI) calcd for C₂₂H₁₁Br₂F₃N₂O₆ MH⁺ 614.9014, found 614.8983.

7-Amino-8-(2-hydroxy-4,6-dimethyl-3,5-dinitrobenzoyl)-2-methyl-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4n)

Yield 0.49 g (92%, method D), mp 271–272 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 2.15 (s, 3H, Me), 2.22 (s, 3H, Me), 2.43 (s, 3H, Me), 7.32 (d, J = 8.4 Hz, 1H, H-4), 7.44 (dd, J = 8.4, 1.3 Hz, 1H, H-3), 7.73 (s, 1H, H-10), 8.27 (br s, 1H, H-1); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 105.8 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 13.2, 15.0, 20.3, 105.4 (q, ³J_C,F = 5.2 Hz), 105.7, 116.5, 116.6, 122.2, 123.2 (q, ¹J_C,F = 275.3 Hz, CF₃), 124.4, 126.6, 128.1 (q, ³J_C,F = 1.3 Hz), 131.4 (q, ²J_C,F = 31.1 Hz, C-9), 132.9, 133.9, 134.5, 138.1, 140.5, 144.0, 149.0, 151.0, 151.4, 161.3, 192.9; IR (ATR/cm⁻¹): ν = 3490, 3336, 1702, 1587, 1539, 1490, 1446, 1362, 1325. Anal. calcd for C₂₄H₁₆F₃N₃O₈·0.5H₂O: С, 53.34; Н, 3.17; N, 7.78. Found: С, 53.46; Н, 3.11; N, 7.76.

7-Amino-2-chloro-8-(2-hydroxy-4,6-dimethyl-3,5-dinitrobenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4o)

Yield 0.49 g (89%, method D), mp 273–274 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 2.15 (s, 3H, Me), 2.24 (s, 3H, Me), 7.46 (d, J = 8.8 Hz, 1H, H-4), 7.66 (dd, J = 8.8, 2.2 Hz, 1H, H-3), 7.84 (s, 1H, H-10), 8.63 (d, J = 2.2 Hz, 1H, H-1); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 105.8 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 13.2, 15.0, 105.4, 105.9 (q, ³J_C,F = 5.1 Hz), 118.7, 118.8, 123.1 (q, ¹J_C,F = 275.4 Hz, CF₃), 123.6, 124.3, 126.7, 127.7, 129.3, 131.1 (q, ²J_C,F = 31.1 Hz, C-9), 131.6, 134.1, 136.6, 140.6, 143.8, 149.5, 150.7, 151.9, 160.9, 192.9; IR (ATR/cm⁻¹): ν = 3492, 3343, 1705, 1586, 1539, 1478, 1444, 1403, 1365, 1322. Anal. calcd for C₂₃H₁₃ClF₃N₃O₈: С, 50.06; Н, 2.37; N, 7.62. Found: С, 49.89; Н, 2.28; N, 5.58.

7-Amino-2-chloro-8-(3,5-dibromo-2-hydroxy-6-nitrobenzoyl)-9-trifluoromethyl-6H-benzo[c]chromen-6-one (4p)

Yield 0.63 g (99%, method D), mp 268–269 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 6.9–8.2 (br s, 2H, NH₂), 7.41 (d, J = 8.8 Hz, 1H, H-4), 7.59 (dd, J = 8.8, 2.0 Hz, 1H, H-3), 7.81 (s, 1H, H-10), 8.24 (s, 1H, H-4′), 8.51 (d, J = 2.0 Hz, 1H, H-1); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 105.5 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 102.7, 105.1, 106.1 (q, ³J_C,F = 4.6 Hz), 117.6, 118.8, 118.9, 120.0, 123.0 (q, ¹J_C,F = 275.5 Hz, CF₃), 124.2, 124.4, 129.4, 131.4 (q, ²J_C,F = 31.6 Hz, C-9), 131.5, 136.1, 140.7, 149.4, 149.7, 149.9, 156.5, 160.9, 189.3; IR (ATR/cm⁻¹): ν = 3485, 3339, 1704, 1610, 1632, 1584, 1538, 1478, 1388. Anal. calcd for C₂₁H₈Br₂ClF₃N₂O₆: С, 39.62; Н, 1.27; N, 4.40. Found: С, 39.78; Н, 1.50; N, 4.54.

7-Amino-8-(2-hydroxy-4,6-dimethyl-3,5-dinitrobenzoyl)-9-(1,1,2,2-tetrafluoroethyl)-6H-benzo[c]chromen-6-one (4q)

Yield 0.54 g (99%, method D), mp 214–215 °C (dec.), yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 2.15 (s, 3H, Me), 2.26 (s, 3H, Me), 6.90 (tt, J = 53.2, 5.8 Hz, 1H, CF₂H), 7.42 (dd, J = 8.2, 1.0 Hz, 1H, H-2), 7.43 (ddd, J = 8.2, 7.2, 1.0 Hz, 1H, H-4), 7.60 (s, 1H, H-10), 7.63 (ddd, J = 8.2, 7.2, 1.1 Hz, 1H, H-3), 8.37 (dd, J = 8.5, 1.1 Hz, 1H, H-1); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 25.3 (ddt, J = 295.3, 53.2, 8.2 Hz, 1F, CFFH), 26.2 (ddt, J = 295.3, 53.2, 8.2 Hz, 1F, CFFH), 52.7 (d, J = 268.9 Hz, 1F, CFF), 54.9 (d, J = 268.9 Hz, 1F, CFF); ¹³C NMR (126 MHz, DMSO-d₆) δ = 13.2, 15.3, 104.6, 106.4 (t, ³J_C,F = 7.3 Hz), 110.0 (tt, ¹J_C,F = 250.0, ²J_C,F = 34.7 Hz, CF₂), 115.6 (tt, ¹J_C,F = 252.2, ²J_C,F = 27.0 Hz, CF₂), 116.9, 117.0, 124.3, 124.9, 125.4, 126.7, 126.9, 131.8, 132.0 (t, ²J_C,F = 23.0 Hz, C-9), 134.4, 136.8, 140.7, 144.0, 150.3, 150.7, 152.6, 161.3, 194.3; IR (ATR/cm⁻¹): ν = 3425, 3335, 3303, 1695, 1604, 1536, 1361. Anal. calcd for C₂₄H₁₅F₄N₃O₈·0.5H₂O: С, 51.62; Н, 2.89; N, 7.53. Found: С, 51.60; Н, 2.44; N, 7.48.

7-Amino-2-chloro-8-(2-hydroxy-4,6-dimethyl-3,5-dinitrobenzoyl)-9-(1,1,2,2-tetrafluoroethyl)-6H-benzo[c]chromen-6-one (4r)

Yield 0.52 g (89%, method D), mp 156–157 °C, yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 2.12 (s, 3H, Me), 2.27 (s, 3H, Me), 6.87 (tt, J = 52.0, 5.8 Hz, 1H, CF₂H), 7.46 (d, J = 8.8 Hz, 1H, H-4), 7.65 (dd, J = 8.8, 2.4 Hz, 1H, H-3), 7.65 (s, 1H, H-10), 8.52 (d, J = 2.4 Hz, 1H, H-1); IR (ATR/cm⁻¹): ν = 3487, 3474, 3339, 1707, 1599, 1538, 1479, 1363, 1313; HRMS (ESI) calcd for C₂₄H₁₄ClF₄N₃O₈ MH⁺ 584.0484, found 584.0473.

7-Amino-8-(2-hydroxy-5-nitrobenzoyl)-9-perfluorobutyl-6H-benzo[c]chromen-6-one (4s)

Yield 0.18 g (30%, method E), mp 240–241 °C, yellow powder; ¹H NMR (500 MHz, DMSO-d₆) δ = 7.06 (d, J = 7.7 Hz, 1H, H-3′), 7.32–7.51 (m, 4H, H-2, H-4, NH₂), 7.63 (ddd, J = 8.2, 7.2, 1.0 Hz, 1H, H-3), 7.67 (s, 1H, H-10), 8.35 (d, J = 7.7 Hz, 1H, H-4′), 8.46 (d, J = 7.7 Hz, 1H, H-1), 8.62 (s, 1H, H-6′), 12.10 (br s, 1H, OH); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 36.7–37.5 (m, 2F, CF₂), 41.2–43.6 (m, 2F, CF₂), 59.4 (d, J = 257.5 Hz, CFF), 55.7 (d, J = 257.5 Hz, CFF), 82.1 (t, J = 9.3 Hz, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 105.0, 106.7 (t, ³J_C,F = 6.5 Hz), 105.7–111.8 (m, 2CF₂), 116.2 (tt, ¹J_C,F = 258.8, ²J_C,F = 33.5 Hz, CF₂), 116.9 (qt, ¹J_C,F = 288.4, ²J_C,F = 33.6 Hz, CF₃), 116.9, 117.0, 118.9, 122.4, 124.4, 125.0, 125.8, 127.6, 130.1 (t, ²J_C,F = 22.9 Hz, C-9), 130.6, 131.7, 136.4, 139.5, 149.2, 150.7, 161.3, 164.7, 192.3; IR (ATR/cm⁻¹): ν = 3480, 1711, 1636, 1596, 1474, 1409, 1346; HRMS (ESI) calcd for C₂₄H₁₁F₉N₂O₆ MH⁺ 595.0552, found 595.0554.

7-Amino-2-bromo-8-(2-hydroxy-5-nitrobenzoyl)-10-methyl-9-(trifluoromethyl)-6H-benzo[c]chromen-6-one (4t)

Yield 0.09 g (17%, method E, 15 days), mp 239–240 °C, yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 2.69 (s, 3H, Me), 7.08 (d, J = 9.1 Hz, 1H, H-3′), 7.19 (s, 2H, NH₂), 7.42 (d, J = 8.7 Hz, 1H, H-4), 7.77 (d, J = 8.7 Hz, 1H, H-3), 8.28 (br s, 1H, H-1), 8.37 (dd, J = 9.1, 2.6 Hz, 1H, H-4′), 8.64 (br s, 1H, H-6′), 12.13 (br s, 1H, OH); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 108.8 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 19.1, 106.2, 115.7, 118.8, 118.9, 119.1, 120.2, 122.0, 123.9 (q, ¹J_C,F = 277.1 Hz, CF₃), 127.2 (q, J = 5.5 Hz), 127.7, 130.8, 130.9, 131.6 (q, ²J_C,F = 28.4 Hz, C-9), 133.3, 135.7, 139.6, 146.5, 149.8, 161.3, 164.7, 192.5; IR (ATR/cm⁻¹): ν = 3491, 3368, 3350, 1714, 1633, 1608, 1595, 1553, 1529, 1469, 1437, 1384, 1339; HRMS (ESI) calcd for C₂₂H₁₂BrF₃N₂O₆ MH⁺ 536.9909, found 536.9921.

7-Amino-2-bromo-8-(2-hydroxy-4,6-dimethyl-3,5-dinitrobenzoyl)-10-methyl-9-(trifluoromethyl)-6H-benzo[c]chromen-6-one (4u)

Yield 0.55 g (90%, method D), mp 234–235 °C, yellow powder; ¹H NMR (400 MHz, CDCl₃) δ = 2.01 (s, 3H, Me), 2.34 (s, 3H, Me), 2.77 (q, J = 2.0 Hz, 3H, Me-10), 6.77 (br s, 2H, NH₂), 7.30 (d, J = 8.7 Hz, 1H, H-4), 7.65 (dd, J = 8.7, 2.1 Hz, 1H, H-3), 8.22 (d, J = 2.1 Hz, 1H, H-1), 12.51 (br s, 1H, OH); ¹H NMR (500 MHz, DMSO-d₆) δ = 2.10 (s, 3H, Me), 2.32 (s, 3H, Me), 2.63 (br s, 3H, Me-10), 7.41 (d, J = 8.7 Hz, 1H, H-4), 7.75 (dd, J = 8.7, 2.0 Hz, 1H, H-3), 8.25 (d, J = 2.0 Hz, 1H, H-1); ¹⁹F NMR (376 MHz, CDCl₃) δ = 107.5 (q, J = 2.0 Hz, CF₃); ¹³C NMR (126 MHz, CDCl₃) δ = 14.3, 15.9, 19.9 (q, ¹J_C,F = 3.6 Hz, CF₃), 108.5, 116.9, 119.2, 119.8, 121.1 (br s), 121.8, 123.5 (q, ¹J_C,F = 277.4 Hz, CF₃), 124.8, 129.7, 133.2 (q, ²J_C,F = 29.4 Hz, C-9), 134.2, 134.7, 138.7, 139.3, 146.2, 146.5, 150.2, 155.5, 161.5, 199.1 (one C atom is not observed); IR (ATR/cm⁻¹): ν = 3377, 3300, 1707, 1671, 1591, 1531, 1477, 1436, 1366; HRMS (ESI) calcd for C₂₄H₁₅BrF₃N₃O₈ MH⁺ 610.0073, found 610.0081.

Triethylammonium (E)-4,6-dibromo-2-[4-(3-cyano-2-oxo-2H-chromen-4-yl)-3-(trifluoromethyl)but-3-enoyl]-3-nitrophenolate (5k)

Yield 0.31 g (44%, method A), mp 154–155 °C (dec.), light yellow prisms; ¹H NMR (400 MHz, CDCl₃) δ = 1.28 (t, J = 7.2 Hz, 9H, 3Me), 3.08 (q, J = 7.2 Hz, 6H, 3CH₂), 4.06 (br d, J = 14.4 Hz, 1H, CHH), 4.73 (br d, J = 14.4 Hz, 1H, CHH), 7.23 (s, 1H, H-4′), 7.25 (q, ⁴J_H,F = 1.5 Hz, 1H, =CH), 7.36 (d, J = 8.2 Hz, 1H, H-8), 7.38 (ddd, J = 8.0, 7.4, 0.9 Hz, 1H, H-6), 7.59 (dd, J = 8.0, 1.3 Hz, 1H, H-5), 7.68 (ddd, J = 8.2, 7.4, 1.3, Hz, 1H, H-7), 12.02 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, CDCl₃) δ = 93.0 (s, CF₃); ¹³C NMR (126 MHz, CDCl₃) δ = 8.7, 40.7, 45.9, 93.3, 100.7, 113.6, 116.7, 117.2, 120.8, 120.9, 122.7 (q, ¹J_C,F = 274.4 Hz, CF₃), 125.6, 126.7, 127.4, 133.5 (q, ²J_C,F = 31.1 Hz), 135.3, 137.4, 149.7, 153.5, 156.7, 157.1, 163.3, 194.1; IR (ATR/cm⁻¹): ν = 2625, 2481, 2228, 1730, 1664, 1690, 599, 1582, 1556, 1534, 1461, 1373, 1340. Anal. calcd for C₂₇H₂₄Br₂F₃N₃O₆: С, 46.11; Н, 3.44; N, 5.97. Found: С, 46.11; Н, 3.46; N, 5.92.

Triethylammonium (E)-2-[4-(3-cyano-2-oxo-2H-chromen-4-yl)-3-(trifluoromethyl)but-3-enoyl]-3,5-dimethyl-4,6-dinitrophenolate (5l)

Yield 0.58 g (93%, method A), mp 164–165 °C (dec.), light yellow prisms; ¹H NMR (400 MHz, CDCl₃) δ = 1.22 (t, J = 7.1 Hz, 9H, 3Me), 1.85 (s, 3H, Me), 1.90 (s, 3H, Me), 3.01 (q, J = 7.1 Hz, 6H, 3CH₂), 3.86 (br d, J = 14.0 Hz, 1H, CHH), 4.67 (br d, J = 14.0 Hz, 1H, CHH), 7.23 (br s, 1H, =CH), 7.35–7.44 (m, 3H, H-5, H-6, H-8), 7.69 (ddd, J = 8.5, 6.8, 1.7 Hz, 1H, H-7), 11.10 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, CDCl₃) δ = 93.7 (s, CF₃); ¹³C NMR (101 MHz, CDCl₃) δ = 8.7, 13.7, 14.9, 42.4, 45.7, 100.0, 101.0, 113.3, 116.7, 117.7, 122.6 (q, ¹J_C,F = 275.1 Hz, CF₃), 125.8, 126.0, 126.9, 128.7, 132.3, 133.8 (q, ²J_C,F = 31.0 Hz), 135.4, 138.1, 142.5, 153.4, 156.4, 156.9, 160.8, 198.8; IR (ATR/cm⁻¹): ν = 2829, 2709, 2232, 1723, 1664, 1602, 1664, 1602, 1574, 1555, 1539, 1516, 1489, 1476, 1454, 1405, 1364, 1344, 1320. Anal. calcd for C₂₉H₂₉F₃N₄O₈: С, 56.31; Н, 4.73; N, 9.06. Found: С, 56.22; Н, 4.80; N, 8.91.

Triethylammonium (E)-4,6-dibromo-2-[4-(3-cyano-6-methyl-2-oxo-2H-chromen-4-yl)-3-(trifluoromethyl)but-3-enoyl]-3-nitrophenolate (5m)

Yield 0.26 g (36%, method A), mp 153–154 °C (dec.), yellow powder; ¹H NMR (400 MHz, CDCl₃) δ = 1.31 (t, J = 7.3 Hz, 9H, 3Me), 2.43 (s, 3H, Me), 3.09 (q, J = 7.3 Hz, 6H, 3CH₂), 3.98 (br d, J = 14.4 Hz, 1H, CHH), 4.83 (br d, J = 14.4 Hz, 1H, CHH), 7.23 (q, J_H,F = 1.5 Hz, 1H, =CH), 7.23 (d, J = 8.5 Hz, 1H, H-8), 7.25 (s, 1H, H-4′), 7.36 (br s, 1H, H-5), 7.47 (dd, J = 8.5, 1.6, Hz, 1H, H-7), 11.99 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, CDCl₃) δ = 93.1 (s, CF₃); ¹³C NMR (126 MHz, CDCl₃) δ = 8.6, 21.0, 40.5, 46.0, 93.2, 100.5, 113.7, 116.4, 116.8, 117.4, 120.7, 122.7 (q, ¹J_C,F = 274.7 Hz, CF₃), 125.6, 126.8, 127.2, 133.3 (q, ²J_C,F = 32.0 Hz), 136.5, 137.4, 149.8, 151.7, 156.8, 156.9, 163.4, 194.1; IR (ATR/cm⁻¹): ν = 2680, 2511, 2236, 1731, 1689, 1560, 1535, 1464, 1379, 1344, 1318. Anal. calcd for C₂₈H₂₆Br₂F₃N₃O₆: С, 46.88; Н, 3.65; N, 5.86. Found: С, 46.70; Н, 3.66; N, 5.78.

Triethylammonium (E)-2-[4-(3-cyano-6-methyl-2-oxo-2H-chromen-4-yl)-3-(trifluoromethyl)but-3-enoyl]-3,5-dimethyl-4,6-dinitrophenolate (5n)

Yield 0.43 g (68%, method A), mp 165–166 °C (dec.), yellow powder; ¹H NMR (400 MHz, CDCl₃) δ = 1.20 (t, J = 7.1 Hz, 9H, 3Me), 1.86 (s, 3H, Me), 1.91 (s, 3H, Me), 2.43 (s, 3H, Me), 3.00 (q, J = 7.1 Hz, 6H, 3CH₂), 3.93 (br d, J = 14.7 Hz, 1H, CHH), 4.57 (br d, J = 14.7 Hz, 1H, CHH), 7.24 (s, 2H, =CH, H-5), 7.28 (d, J = 8.5 Hz, 1H, H-8), 7.51 (d, J = 8.5 Hz, 1H, H-7), 11.08 (br s, 1H, NH⁺); ¹H NMR (400 MHz, DMSO-d₆) δ = 1.18 (t, J = 7.3 Hz, 9H, 3Me), 1.69 (br s, 3H, Me), 1.87 (br s, 3H, Me), 2.37 (s, 3H, Me), 3.09 (q, J = 7.3 Hz, 6H, 3CH₂), 4.32 (br s, 2H, CH₂), 7.34 (d, J = 8.5 Hz, 1H, H-8), 7.38 (s, 1H, H-5), 7.44 (br s, 1H, =CH), 7.56 (d, J = 8.5 Hz, 1H, H-7), 8.93 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, CDCl₃) δ = 93.7 (s, CF₃); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 96.5 (s, CF₃); ¹³C NMR (126 MHz, CDCl₃) δ = 8.7, 13.8, 15.1, 21.0, 42.3, 45.8, 100.8, 113.5, 116.5, 117.4, 122.7 (q, ¹J_C,F = 274.8 Hz, CF₃), 126.3, 126.5, 126.9 (q, ³J_C,F = 5.9 Hz), 128.9, 132.6, 133.8 (q, ²J_C,F = 31.1 Hz), 136.0, 136.9, 137.9, 142.7, 151.7, 156.6, 156.9, 161.0, 198.8; IR (ATR/cm⁻¹): ν = 2232, 1731, 1704, 1616, 1575, 1534, 1478, 1406, 1347. Anal. calcd for C₃₀H₃₁F₃N₄O₈: С, 56.96; Н, 4.94; N, 8.86. Found: С, 57.03; Н, 5.09; N, 8.70.

Triethylammonium (E)-2-[4-(6-chloro-3-cyano-2-oxo-2H-chromen-4-yl)-3-(trifluoromethyl)but-3-enoyl]-3,5-dimethyl-4,6-dinitrophenolate (5o)

Yield 0.37 g (57%, method A), mp 162–163 °C (dec.), yellow powder; ¹H NMR (400 MHz, CDCl₃) δ = 1.26 (t, J = 7.3 Hz, 9H, 3Me), 1.91 (s, 3H, Me), 1.98 (s, 3H, Me), 3.05 (q, J = 7.3 Hz, 6H, 3CH₂), 3.95 (br d, J = 14.5 Hz, 1H, CHH), 4.56 (br d, J = 14.5 Hz, 1H, CHH), 7.20 (br s, 1H, =CH), 7.35 (d, J = 8.9 Hz, 1H, H-8), 7.46 (d, J = 2.2 Hz, 1H, H-5), 7.66 (dd, J = 8.9, 2.2, Hz, 1H, H-7), 11.20 (br s, 1H, NH⁺); ¹⁹F NMR (376 MHz, CDCl₃) δ = 93.4 (s, CF₃); IR (ATR/cm⁻¹): ν = 2624, 2496, 2232, 1751, 1687, 1577, 1535, 1479, 1412, 1344. Anal. calcd for C₂₉H₂₈ClF₃N₄O₈: С, 53.34; Н, 4.32; N, 8.58. Found: С, 53.31; Н, 4.11; N, 8.57.

General procedure for the synthesis of compounds 6

Method F. A suspension of salt 5 (1.0 mmol) in concentrated HCl (8 mL) was stirred at room temperature for 15 min. After cooling, the resultant precipitate was filtered and washed with water (5 × 5 mL).

(E)-4-[4-(3,5-Dibromo-2-hydroxy-6-nitrophenyl)-4-oxo-2-(trifluoromethyl)but-1-en-1-yl]-2-oxo-2H-chromene-3-carbonitrile (6k)

Yield 0.56 g (92%), mp 198–199 °C, white powder; ¹H NMR (500 MHz, DMSO-d₆) δ = 4.09 (br d, J = 17.6 Hz, 1H, CHH), 4.32 (br d, J = 17.6 Hz, 1H, CHH), 7.48 (t, J = 7.6 Hz, 1H, H-6), 7.56 (d, J = 8.4 Hz, 1H, H-8), 7.59 (br d, J = 8.0 Hz, 1H, H-5), 7.83 (t, J = 7.7, Hz, 1H, H-7), 7.85 (br s, 1H, =CH), 8.12 (s, 1H, H-4′); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 95.9 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 40.6, 101.0, 103.2, 112.3, 113.3, 116.2, 117.0, 117.6, 122.6 (q, ¹J_C,F = 274.9 Hz, CF₃), 125.4, 127.7, 129.0, 130.1 (q, ²J_C,F = 31.0 Hz), 130.7, 135.8, 138.7, 147.4, 152.5, 156.2, 157.1, 192.9; IR (ATR/cm⁻¹): ν = 3465, 2235, 1710, 1596, 1555, 1538, 1439, 1377, 1354. Anal. calcd for C₂₁H₉Br₂F₃N₂O₆: С, 41.89; Н, 1.51; N, 4.65. Found: С, 41.74; Н, 1.45; N, 4.76.

(E)-4-[4-(2-Hydroxy-4,6-dimethyl-3,5-dinitrophenyl)-4-oxo-2-(trifluoromethyl)but-1-en-1-yl]-2-oxo-2H-chromene-3-carbonitrile (6l)

Yield 0.48 g (93%, method E), mp 192–193 °C, light yellow powder; ¹H NMR (400 MHz, CDCl₃) δ = 2.03 (s, 3H, Me), 2.45 (s, 3H, Me), 3.97 (br s, 1H, CHH), 4.11 (br s, 1H, CHH), 7.41–7.51 (m, 3H, =CH, H-6, H-8), 7.73–7.82 (m, 2H, H-5, H-7), 10.45 (br s, 1H, OH); ¹H NMR (400 MHz, DMSO-d₆) δ = 1.58 (s, 3H, Me), 2.07 (s, 3H, Me), 4.05 (br d, J = 18.6 Hz, 1H, CHH), 4.24 (br d, J = 18.6 Hz, 1H, CHH), 7.49 (t, J = 7.6 Hz, 1H, H-6), 7.55 (d, J = 8.2 Hz, 1H, H-8), 7.64 (d, J = 8.1 Hz, 1H, H-5), 7.82 (t, J = 7.7 Hz, 1H, H-7), 7.85 (s, 1H, =CH); ¹⁹F NMR (376 MHz, CDCl₃) δ 93.0 (s, CF₃); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 96.4 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 13.0, 13.6, 41.4, 101.6, 113.3, 116.4, 117.1, 122.7 (q, ¹J_C,F = 276.4 Hz, CF₃), 124.9, 125.4, 128.0, 130.3, 130.6 (q, ²J_C,F = 30.9 Hz), 130.7, 135.9, 139.2, 143.9, 147.6, 153.1, 156.3, 157.0, 197.2 (one C atom is not observed); IR (ATR/cm⁻¹): ν = 3333, 2215, 1727, 1595, 1532, 1448, 1354. Anal. calcd for C₂₃H₁₄F₃N₃O₈: С, 53.40; Н, 2.73; N, 8.12. Found: С, 53.31; Н, 2.78; N, 8.01.

(E)-4-[4-(3,5-Dibromo-2-hydroxy-6-nitrophenyl)-4-oxo-2-(trifluoromethyl)but-1-en-1-yl]-6-methyl-2-oxo-2H-chromene-3-carbonitrile (6m)

Yield 0.31 g (72%), mp 204–205 °C, white powder; ¹H NMR (500 MHz, DMSO-d₆) δ = 2.39 (s, 3H, Me), 4.07 (br d, J = 17.0 Hz, 1H, CHH), 4.33 (br d, J = 17.0 Hz, 1H, CHH), 7.34 (br s, 1H, H-5), 7.45 (d, J = 8.5 Hz, 1H, H-8), 7.64 (d, J = 8.5 Hz, 1H, H-7), 7.80 (br s, 1H, =CH), 8.10 (s, 1H, H-4′); ¹⁹F NMR (471 MHz, DMSO-d₆) δ = 96.0 (s, CF₃); IR (ATR/cm⁻¹): ν = 3322, 2229, 1720, 1554, 1535, 1445, 1354, 1312. Anal. calcd for C₂₂H₁₁Br₂F₃N₂O₆: С, 42.89; Н, 1.80; N, 4.55. Found: С, 42.68; Н, 1.72; N, 4.47.

(E)-4-[4-(2-Hydroxy-4,6-dimethyl-3,5-dinitrophenyl)-4-oxo-2-(trifluoromethyl)but-1-en-1-yl]-6-methyl-2-oxo-2H-chromene-3-carbonitrile (6n)

Yield 0.49 g (93%), mp 220–221 °C, white powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 1.57 (s, 3H, 3Me), 2.08 (s, 3H, Me), 2.39 (s, 3H, Me), 4.05 (br d, J = 17.8 Hz, 1H, CHH), 4.22 (br d, J = 17.8 Hz, 1H, CHH), 7.36–7.52 (m, 2H, H-8, H-5), 7.64 (d, J = 8.2 Hz, 1H, H-7), 7.80 (br s, 1H, =CH); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 96.4 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 12.9, 13.5, 20.2, 41.4, 101.3, 113.3, 116.1, 116.8 (2C), 122.7 (q, ¹J_C,F = 274.3 Hz, CF₃), 124.8, 127.4, 130.6 (q, ²J_C,F = 32.1 Hz), 130.7, 136.8, 139.9, 143.8, 147.6, 151.4, 156.4, 157.0, 186.6, 197.3 (one C atom is not observed); IR (ATR/cm⁻¹): ν = 2232, 1722, 1608, 1591, 1554, 1532, 1446, 1351, 1312. Anal. calcd for C₂₄H₁₆F₃N₃O₈: С, 54.25; Н, 3.04; N, 7.91. Found: С, 54.09; Н, 3.15; N, 7.91.

(E)-6-Chloro-4-[4-(2-hydroxy-4,6-dimethyl-3,5-dinitrophenyl)-4-oxo-2-(trifluoromethyl)but-1-en-1-yl]-2-oxo-2H-chromene-3-carbonitrile (6o)

Yield 0.50 g (91%), mp 224–225 °C, light yellow powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 1.60 (s, 3H, 3Me), 2.08 (s, 3H, Me), 4.11 (br d, J = 17.0 Hz, 1H, CHH), 4.23 (br d, J = 17.0 Hz, 1H, CHH), 7.60 (d, J = 8.6 Hz, 1H, H-8), 7.69 (br s, 1H, H-5), 7.82 (br s, 1H, =CH), 7.87 (d, J = 8.6 Hz, 1H, H-7); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 96.3 (s, CF₃); IR (ATR/cm⁻¹): ν = 2235, 1733, 1702, 1592, 1547, 1528, 1478, 1440, 1416, 1353, 1315; HRMS (ESI) calcd for C₂₃H₁₃ClF₃N₃O₈ MH⁺ 552.0422, found 552.0428.

4-[(6,8-Dibromo-5-nitro-4-oxo-2-(trifluoromethyl)chroman-2-yl)methyl]-2-oxo-2H-chromene-3-carbonitrile (7k)

A solution of compound 6k (60 mg, 0.10 mmol) in DMSO (1 mL) was kept at room temperature for 6 days. Then water (5 mL) was added and the resultant precipitate was filtered and washed with water (4 × 5 mL). Yield 45 mg (75%), mp 134–135 °C, beige powder; ¹H NMR (400 MHz, CDCl₃) δ = 3.22 (d, J = 17.2 Hz, 1H, CHH), 3.40 (d, J = 17.2 Hz, 1H, CHH), 3.65 (d, J = 14.6 Hz, 1H, CHH), 4.07 (d, J = 14.6 Hz, 1H, CHH), 7.43 (d, J = 8.1 Hz, 1H, H-8), 7.46 (t, J = 7.6 Hz, 1H, H-6), 7.75 (t, J = 7.8 Hz, 1H, H-7), 7.99 (s, 1H, H-7′), 8.03 (d, J = 7.7 Hz, 1H, H-5); ¹H NMR (400 MHz, DMSO-d₆) δ = 3.30 (d, J = 17.3 Hz, 1H, CHH), 3.63 (d, J = 15.0 Hz, 1H, CHH), 3.95 (d, J = 17.3 Hz, 1H, CHH), 4.27 (d, J = 15.0 Hz, 1H, CHH), 7.52 (d, J = 8.4 Hz, 1H, H-8), 7.56 (t, J = 7.8 Hz, 1H, H-6), 7.83 (t, J = 7.9 Hz, 1H, H-7), 8.21 (dd, J = 8.1, 1.2 Hz, 1H, H-5), 8.56 (s, 1H, H-7′); ¹⁹F NMR (376 MHz, DMSO-d₆) δ = 84.9 (s, CF₃); ¹³C NMR (126 MHz, DMSO-d₆) δ = 33.9, 37.8, 83.0 (q, ²J_C,F = 28.8 Hz), 106.4, 106.9, 114.3, 116.9, 118.0, 122.6 (q, ¹J_C,F = 274.9 Hz, CF₃), 125.4, 127.7, 129.0, 135.6, 142.8, 145.3, 152.9, 153.1, 153.8, 156.2, 156.6, 183.6; IR (ATR/cm⁻¹): ν = 2233, 1723, 1603, 1553, 1443, 1379; HRMS (ESI) calcd for C₂₁H₉Br₂F₃N₂O₆ MH⁺ 600.8858, found 600.8829.

4-[(5,7-Dimethyl-6,8-dinitro-4-oxo-2-(trifluoromethyl)chroman-2-yl)methyl]-2-oxo-2H-chromene-3-carbonitrile (7l)

A solution of compound 6l (52 mg, 0.10 mmol) in DMSO (1 mL) was kept at room temperature for 15 days. Then water (5 mL) was added and the resultant precipitate was filtered, washed with water (4 × 5 mL), dried and recrystallized from ethyl acetate–hexane (5 : 1). Yield 61%, mp 159–160 °C, white powder; ¹H NMR (400 MHz, DMSO-d₆) δ = 2.17 (s, 3H, Me), 2.40 (s, 3H, Me), 3.24 (d, J = 16.6 Hz, 1H, CHH), 3.66 (d, J = 15.2 Hz, 1H, CHH), 3.84 (d, J = 16.6 Hz, 1H, CHH), 4.14 (d, J = 15.2 Hz, 1H, CHH), 7.47 (t, J = 7.8 Hz, 1H, H-6), 7.53 (d, J = 8.2 Hz, 1H, H-8), 7.83 (ddd, J = 8.3, 7.3, 1.2 Hz, 1H, H-7), 7.95 (d, J = 8.3 Hz, 1H, H-5); IR (ATR/cm⁻¹): ν = 2211, 1739, 1605, 1538, 1450, 1359; HRMS (ESI) calcd for C₂₃H₁₄F₃N₃O₈ MH⁺ 518.0811, found 518.0793.

Crystallographic data for compounds 3n, 4h, 5k, 5l and 6l

Intensity data for the compounds 3n, 4h, 5k–l and 6l were collected on a “Xcalibur E” and “Xcalibur S” diffractometers at 295(2) K (Mo-Kα radiation, graphite monochromator, multi-scan, radiation wavelength = 0.7107). The structures were solved by direct methods and refined by full-matrix least-squares method using the SHELX-97 program package.²⁹ All non-hydrogen atoms were refined with anisotropic atomic displacement and hydrogen atoms were included at calculated position using a riding model.

Crystal data for 3n. C₃₀H₃₁F₃N₄O₈, M = 632.59. Triclinic crystals space group P1̄, a = 11.5613(7), b = 12.0502(7), c = 13.5247(7) Å, α = 116.093(6), β = 98.200(5), γ = 108.429(5)°, V = 1515.13(15) ų, D_c = 1.387 g cm⁻³, absorption coefficient μ = 0.113 mm⁻¹, Z = 2. The intensities of 8251 independent reflections (R_int = 0.0179) were measured. The final discrepancy factors R₁ = 0.0557, wR₂ = 0.1617, GooF = 1.003 for 5266 reflections with I > 2σ(I); R₁ = 0.0915, wR₂ = 0.1903 (all data). Largest different peak and hole: 0.332 and −0.258 eÅ⁻³. Completeness to θ = 28.22° (99.99%). Deposition number CCDC 1465050.

Crystal data for 4h. C₂₁H₁₁F₃N₂O₆, M = 444.32. Monoclinic crystals space group P2₁/n, a = 13.8312(6), b = 6.5653(2), c = 20.2552(9) Å, α = γ = 90.00, β = 96.187(4)°, V = 1828.58(13) ų, D_c = 1.614 g cm⁻³, absorption coefficient μ = 0.139 mm⁻¹, Z = 4. The intensities of 4037 independent reflections (R_int = 0.0205) were measured. The final discrepancy factors R₁ = 0.0459, wR₂ = 0.1144, GooF = 1.002 for 2863 reflections with I > 2σ(I); R₁ = 0.0850, wR₂ = 0.1372 (all data). Largest different peak and hole: 0.179 and −0.182 eÅ⁻³. Completeness to θ = 27.10° (99.95%). Deposition number CCDC 1465073.

Crystal data for 5k. C₂₇H₂₄Br₂F₃N₃O₆, M = 703.31. Monoclinic crystals space group P2₁/c, a = 18.0863(13), b = 12.0796(6), c = 14.2137(12) Å, α = γ = 90.00, β = 112.926(10)°, V = 2860.0(4) ų, D_c = 1.633 g cm⁻³, absorption coefficient μ = 2.900 mm⁻¹, Z = 4. The intensities of 6767 independent reflections (R_int = 0.0307) were measured. The final discrepancy factors R₁ = 0.0527, wR₂ = 0.1335, GooF = 1.007 for 4051 reflections with I > 2σ(I); R₁ = 0.1054, wR₂ = 0.1659 (all data). Largest different peak and hole: 0.967 and −0.985 eÅ⁻³. Completeness to θ = 28.22° (94.39%). Deposition number CCDC 1465074.

Crystal data for 5l. C₂₉H₂₉F₃N₄O₈, M = 618.57. Monoclinic crystals space group P2₁/c, a = 17.6138(12), b = 12.2004(5), c = 14.8315(13) Å, α = γ = 90.00, β = 113.227(9)°, V = 2928.9(3) ų, D_c = 1.403 g cm⁻³, absorption coefficient μ = 0.115 mm⁻¹, Z = 4. The intensities of 7256 independent reflections (R_int = 0.0380) were measured. The final discrepancy factors R₁ = 0.0639, wR₂ = 0.1375, GooF = 1.000 for 4051 reflections with I > 2σ(I); R₁ = 0.1630, wR₂ = 0.1839 (all data). Largest different peak and hole: 0.279 and −0.239 eÅ⁻³. Completeness to θ = 28.28° (99.9%). Deposition number CCDC 1465067.

Crystal data for 6l. C₂₃H₁₄F₃N₃O₈, M = 517.37. Triclinic crystals space group P1̄, a = 10.5239(5), b = 11.2068(6), c = 20.6780(10) Å, α = 104.099(4), β = 96.924(4), γ = 99.452(4)°, V = 2300.1(2) ų, D_c = 1.494 g cm⁻³, absorption coefficient μ = 0.130 mm⁻¹, Z = 4. The intensities of 10 110 independent reflections (R_int = 0.0396) were measured. The final discrepancy factors R₁ = 0.0617, wR₂ = 0.1317, GooF = 1.005 for 4559 reflections with I > 2σ(I); R₁ = 0.1581, wR₂ = 0.1799 (all data). Largest different peak and hole: 0.381 and −0.224 eÅ⁻³. Completeness to θ = 28.22° (88.71%). Deposition number CCDC 1465075.

Acknowledgements

This work was supported financially by the Russian Foundation for Basic Research (Grant No. 14-03-00179), the Act 211 Government of the Russian Federation (agreement No. 02.A03.21.0006), and performed within the State Task from the Ministry of Education and Science of Russian Federation.

Notes and References

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Footnote

† Electronic supplementary information (ESI) available: Copies of ¹H, ¹⁹F, and ¹³C NMR spectra of compounds obtained. CCDC 1465050, 1465067 and 1465073–1465075. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6ra12492e

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