DOI:
10.1039/C6RA17032C
(Paper)
RSC Adv., 2016,
6, 73953-73958
Synthesis and anti-proliferative activity evaluation of novel 1,4-naphthoquinones possessing pyrido[2,3-d]pyrimidine scaffolds†
Received
3rd July 2016
, Accepted 27th July 2016
First published on 29th July 2016
Abstract
A series of novel 1,4-naphthoquinones possessing pyrido[2,3-d]pyrimidine scaffolds were synthesized in very good yields using one-pot condensation of 2-hydroxy-1,4-naphthoquinone, aldehydes, and 2-substituted 4,6-diaminopyrimidine. The in vitro anti-proliferative activity of these novel compounds was evaluated in SGC7901 and HepG2 cell lines. Almost all the tested compounds showed manifested potent inhibitory activity against the two tested cancer cell lines.
Introduction
Multicomponent reactions (MCRs) have become a powerful protocol to access pharmaceutically relevant heterocycles in recent years because of their combined prominent features such as high reaction rate and efficiency, atom economy and selectivity, time and energy savings, target product specificity and minimal environmental impact.1
Natural products and pharmaceuticals embedded with 1,4-naphthoquinone units display potential medicinal properties such as anticancer,2 antifungal,3 antibacterial,4 antiviral,5 anti-inflammatory,6 antimalaria,7 antiplatelet,5 antithrombotic,8 and antiallergic, activities.9 Furthermore, 1,4-naphthoquinones have also been shown to inhibit human DNA topoisomerase.10 A number of 1,4-naphthoquinone derivatives having nitrogen atom present in them received a great deal of attention for their anticancer activity.11 Therefore, the development of facile approaches to access these novel targets with structural diversity is highly desirable and valuable for medicinal chemistry and drug discovery.
Nitrogen containing heterocycles constitute an important class of compounds. Among them, pyrido[2,3-d]pyrimidine ring system occurs as a principal core skeleton among the drug scaffolds and also play crucial role as an important component in organic synthesis, and medicinal chemistry. Pyrido[2,3-d]pyrimidine derivatives gained prominence as they exhibit a wide range of biological and medicinal properties such as analgesic,12 antiviral,13 anti-inflammatory,14 antimicrobial,15 antifungal,16 and anticancer activity.17 Therefore, the synthesis of diverse structures belonging to this class of compounds is very important.
In the design of new drug prototypes, the concept of molecular hybridization is a useful tool and is based on the combination of pharmacophoric moieties of different bioactive substances to produce a new hybrid compound with improved affinity and efficacy. This strategy has resulted in compounds with modified selectivity profile, different and/or dual mode of action and reduced undesired side effects.18 Based on the versatile bioactivities of the above mentioned structures, it is promising that the integration of pyrido[2,3-d]pyrimidine scaffold with 1,4-naphthoquinone segment might result in the discovery of new drug candidates with unknown or enhanced bioactivities. We herein represent the synthesis of a series of novel 1,4-naphthoquinone and pyrido[2,3-d]pyrimidine hybrids and their anti-proliferative activity against human cancer cell lines in vitro (Scheme 1).
 |
| Scheme 1 | |
Results and discussion
Our strategy to synthesize 1,4-naphthoquinones-fused pyrido[2,3-d]pyrimidines involved three-component reaction of 2-hydroxy-1,4-naphthoquinone, aldehydes, and 2-substituted 4,6-diaminopyrimidine. The initial experiments were performed with 2-hydroxy-1,4-naphthoquinone, benzaldehyde, and 2,4,6-triaminopyrimidine in EtOH at 70 °C for 4 h. This set of conditions led to expected 5-phenyl-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione 4a, albeit in a low 15% yield (Table 1, entry 1). Encouraged by this preliminary result, we optimized the reaction conditions further. Solvent effects were first investigated (Table 1, compare entries 1–7). The use of AcOH facilitated the transformation and delivered 4a in a higher yield of 41%, whereas THF, CHCl3 and H2O, as reaction media completely suppressed the reaction. Another two solvents, that is, toluene and DMF, were proven ineffective and gave outcomes inferior to that obtained with AcOH. We then attempted to adjust the temperature to improve the reaction efficiency. Elevating the temperature to 118 °C (reflux) proved more efficient, and expected 4a was afforded in 65% yield (Table 1, entry 11).
Table 1 Reaction conditions optimization for the synthesis 5-phenyl-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione
Entry |
Solvent |
T/°C |
Time/h |
Yield/% |
1 |
EtOH |
70 |
4 |
15 |
2 |
THF |
62 |
6 |
6 |
3 |
CHCl3 |
61 |
6 |
0 |
4 |
H2O |
70 |
8 |
0 |
5 |
Toluene |
70 |
5 |
10 |
6 |
DMF |
70 |
4 |
39 |
7 |
AcOH |
70 |
4 |
41 |
8 |
AcOH |
80 |
4 |
43 |
9 |
AcOH |
90 |
3 |
49 |
10 |
AcOH |
100 |
2 |
60 |
11 |
AcOH |
118 |
2 |
65 |
Under the above optimized conditions, the substrate scope of this three-component cyclocondensation reaction was examined by using readily available starting materials. As revealed in Table 2, 2,4,6-triaminopyrimidine was first subjected to the reaction with 2-hydroxy-1,4-naphthoquinone and different aldehydes in AcOH at reflux without the use of a strong acid or metal catalyst, and expected 1,4-naphthoquinones possessing pyrido[2,3-d]pyrimidines scaffolds 4a–p were obtained in good yields. Various aryl aldehydes having substituents at different positions with electron-poor (e.g., fluoro, chloro and nitro), electron-neutral (e.g., H), electron-rich (e.g., methyl and methoxy) groups, aromatic heterocyclic and aliphatic aldehydes were compatible. Next, we selected 2-methylthio-4,6-diaminopyrimidine as representative substrate to expand the synthetic utility of this methodology further. As we expected, these reactions proceeded smoothly to give access to corresponding tetracyclic products 4q–s. Resulting 1,4-naphthoquinones possessing pyrido[2,3-d]pyrimidine scaffolds 4 were fully characterized by IR, NMR spectroscopy and HRMS. The IR spectrum of 4a showed absorptions at 1675 and 1633 cm−1 indicating the presence of two C
O bonds. The high resolution mass spectrum of 4a displayed the quasi-molecular ion ([M + Na]+) peak at m/z = 392.1114, which was consistent with the 1
:
1
:
1 adduct of 2-hydroxy-1,4-naphthoquinone, benzaldehyde and 2,4,6-diaminopyrimidine with the loss of two water molecule. The 1H NMR spectrum of 4a showed four singlet was observed (δ = 5.31, 5.82, 6.23 and 8.68 ppm) for the CH group of C-5 position, NH2 group of C-2, 4 position and NH group of dihydropyridine respectively. The 13C NMR spectrum of 4a showed characteristic signals at δ = 34.8 ppm (due to the R1–CH group), 181.7 and 179.9 ppm (arising from the two nonequivalent carbonyl groups).
Table 2 Preparation of 1,4-naphthoquinones possessing pyrido[2,3-d]pyrimidine scaffolds
Entry |
R1 |
R2 |
Time/h |
Product |
Mp/°C |
Yield/% |
1 |
C6H5 |
NH2 |
2 |
4a |
168–170 |
65 |
2 |
2-Thienyl |
NH2 |
2 |
4b |
254–255 |
69 |
3 |
2-Furanyl |
NH2 |
3 |
4c |
297–299 |
59 |
4 |
3-NO2-C6H4 |
NH2 |
3 |
4d |
>300 |
53 |
5 |
4-Cl-C6H4 |
NH2 |
3 |
4e |
165–167 |
57 |
6 |
2,4-Cl-C6H3 |
NH2 |
1.5 |
4f |
>300 |
72 |
7 |
4-F-C6H4 |
NH2 |
3 |
4g |
157–159 |
55 |
8 |
2-F-C6H4 |
NH2 |
1.5 |
4h |
>300 |
71 |
9 |
4-MeO-C6H4 |
NH2 |
1 |
4i |
196–198 |
79 |
10 |
2,5-MeO-C6H3 |
NH2 |
2 |
4j |
265–266 |
63 |
11 |
3,4,5-MeO-C6H2 |
NH2 |
3 |
4k |
276–278 |
60 |
12 |
3-Br-4-MeO-C6H3 |
NH2 |
3 |
4l |
234–236 |
58 |
13 |
C4H9 |
NH2 |
4 |
4m |
192–194 |
50 |
14 |
C5H11 |
NH2 |
4 |
4n |
193–195 |
51 |
15 |
3-OH-C6H4 |
NH2 |
2.5 |
4o |
292–293 |
57 |
16 |
2-CH3-C6H4 |
NH2 |
3 |
4p |
173–175 |
66 |
17 |
4-Cl-C6H4 |
SCH3 |
3 |
4q |
258–260 |
52 |
18 |
C6H5 |
SCH3 |
3 |
4r |
237–239 |
53 |
19 |
3-Br-4-OCH3-C6H3 |
SCH3 |
3 |
4s |
>300 |
55 |
A reasonable mechanism is proposed for the formation of 1,4-naphthoquinones possessing pyrido[2,3-d]pyrimidine scaffolds 4 (Scheme 2). It is conceivable that 2-hydroxy-1,4-naphthoquinone initially reacts with aldehyde 2 to form olefin 5, which underwent a nucleophilic addition of 2-substituted 4,6-diaminopyrimidine to form the corresponding Michael-type type intermediate 6. This step is then followed by an intramolecular dehydration to yield to product 4.
 |
| Scheme 2 | |
To evaluate their anti-proliferative potential, the newly synthesized hybrids 4a–s were subjected to in vitro biological assessment against two human cancer cell lines, SGC7901 and HepG2. The results of the cytotoxicity evaluation, as compared to the anticancer reference compound doxorubicin, were summarized in Table 3. As evidenced by these results, the majority of the derivatives exhibited at least moderate cytotoxic activity against the SGC7901 and HepG2 cell lines. Six of the new hybrids (4b, 4d, 4n, 4q, 4r and 4s) even display a considerable activity profile with IC50 values below 10 μM against both cell lines. It is worthwhile to note that the majority compounds have lesser cytotoxicity on non-cancerous L02 cells. These results clearly suggest the relevance of this interesting new class of hybrids in the framework of cancer therapy research and medicinal chemistry. The results in Table 3 showed also some important structure–activity relationships (SARs) for this series of derivatives. First, the nature of substituents at the C-2 position have substantial influence on the anti-proliferative activity, introduction of methylmercapto group into the C-2 position was found to be quite favorable for increasing anti-proliferative activity. Among this series, compound 4s showed the best anti-proliferative activity with IC50 values of 4.39 μM and 5.91 μM against SGC7901 and HepG2 cell lines, respectively. Second, the substituents at the C-2 moiety appeared to have an important effect upon cytotoxicity, introduction of aromatic heterocycle group into the C-5 position was found to be quite favorable for increasing anti-proliferative activity.
Table 3 Anti-proliferative activities of 1,4-naphthoquinones possessing pyrido[2,3-d]pyrimidine scaffolds
Compound |
IC50 (μM) |
SGC7901 |
HepG2 |
L02 |
4a |
38.86 ± 2.38 |
29.59 ± 1.43 |
80.26 ± 3.23 |
4b |
5.88 ± 0.15 |
9.54 ± 0.51 |
24.54 ± 0.98 |
4c |
10.15 ± 1.01 |
18.52 ± 1.26 |
45.23 ± 2.53 |
4d |
9.79 ± 1.12 |
9.98 ± 1.21 |
25.31 ± 1.20 |
4e |
31.00 ± 2.78 |
42.21 ± 1.98 |
70.21 ± 2.32 |
4f |
>100 |
79.64 ± 8.42 |
>100 |
4g |
30.34 ± 1.67 |
28.16 ± 3.01 |
63.25 ± 2.99 |
4h |
36.34 ± 1.25 |
33.88 ± 5.21 |
>100 |
4i |
10.02 ± 0.89 |
16.28 ± 1.59 |
24.29 ± 1.72 |
4j |
33.74 ± 1.26 |
53.02 ± 2.87 |
>100 |
4k |
26.45 ± 1.36 |
21.55 ± 1.53 |
50.78 ± 2.42 |
4l |
43.63 ± 4.07 |
67.95 ± 9.01 |
>100 |
4m |
26.48 ± 1.29 |
56.81 ± 9.56 |
>100 |
4n |
9.91 ± 1.01 |
8.25 ± 0.84 |
17.53 ± 0.76 |
4o |
25.54 ± 1.04 |
22.20 ± 1.07 |
41.20 ± 1.75 |
4p |
51.05 ± 1.32 |
39.57 ± 1.87 |
>100 |
4q |
5.61 ± 0.43 |
9.15 ± 0.85 |
19.52 ± 0.99 |
4r |
9.46 ± 0.55 |
9.99 ± 0.98 |
18.45 ± 1.32 |
4s |
4.39 ± 0.19 |
5.91 ± 0.73 |
11.26 ± 1.05 |
Doxorubicin |
3.18 ± 0.54 |
2.25 ± 0.42 |
6.22 ± 0.95 |
Conclusion
In the present study, a novel hybrids containing 1,4-naphthoquinone and pyrido[2,3-d]pyrimidine has been developed by molecular hybridization strategy. Nineteen hybrids were synthesized and evaluated for their anti-proliferative activities against SGC7901 and HepG2. The results showed that most of the new compounds showed good to potent cytotoxic activities. The most potent derivative 4s displayed significant inhibition of SGC7901 with an IC50 of 4.39 μM and an IC50 value of 5.91 μM. Therefore, these novel 1,4-naphthoquinones fused with bioactive heterocyclic skeletons may find their pharmaceutical applications after further investigations.
Experimental
General
IR spectra were determined on FTS-40 infrared spectrometer. NMR spectra were determined on Bruker AV-400 spectrometer at room temperature using TMS as internal standard. Chemical shifts (d) are given in ppm and coupling constants (J) in Hz. High resolution mass spectra were recorded on a Bruker micrOTOF-QIII mass spectrometer. Elemental analysis were performed by a Vario-III elemental analyzer. Melting points were determined on a XT-4 binocular microscope and were uncorrected. Commercially available reagents were used throughout without further purification unless otherwise stated.
General procedure for the synthesis of compounds 4
To a mixture of 2-hydroxy-1,4-naphthoquinone (1 mmol), aldehyde (1 mmol) and 2-substituted 4,6-diaminopyrimidine (1 mmol), AcOH (10 mL)was added. The mixture was stirred at reflux for an appropriate time (Table 2). After completion of the reaction (TLC), the reaction mixture was cooled to room temperature and the solvent was evaporated under reduced pressure. Then, the crude product was washed sequentially with 20 mL saturated NaHCO3 and 20 mL brine, purified by silica gel column chromatography using CHCl3
:
ethyl acetate (v/v = 10
:
1) as eluent to afford the pure product 4.
5-Phenyl-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4a). Reddish-brown power, mp 168–170 °C; IR (KBr): ν 3473, 3383, 3302, 3155, 1675, 1633 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.68 (s, 1H), 8.01–7.99 (m, 1H), 7.93–7.91 (m, 1H), 7.84–7.75 (m, 2H), 7.40 (d, 2H, J = 7.2 Hz), 7.21 (t, 2H, J = 7.6 Hz), 7.13 (d, 1H, J = 7.2 Hz), 6.23 (s, 2H), 5.82 (s, 2H), 5.31 (s, 1H); 13C NMR (100 MHz, DMSO-d6) δ: 181.7, 179.9, 162.6, 162.1, 154.1, 145.9, 139.9, 135.3, 133.5, 132.5, 130.7, 128.5, 128.4, 126.8, 126.3, 126.1, 118.4, 87.4, 34.8; HRMS-ESI (m/z): calc for C21H15N5NaO2 [M + Na]+: 392.1123, found: 392.1114.
5-(Thien-2-yl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4b). Reddish-brown power, mp 254–255 °C; IR (KBr): ν 3500, 3467, 3387, 3284, 1676, 1623 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.86 (s, 1H), 8.00 (d, 2H, J = 7.6 Hz), 7.87–7.77 (m, 2H), 7.23 (d, 1H, J = 4.0 Hz), 6.94 (d, 1H, J = 0.8 Hz), 6.85–6.83 (m, 1H), 6.40 (s, 2H), 5.85 (m, 2H), 5.70 (s, 1H); 13C NMR (100 MHz, DMSO-d6) δ: 181.6, 180.0, 162.7, 162.2, 154.0, 149.4, 139.6, 135.4, 133.6, 132.5, 130.7, 126.9, 126.3, 126.2, 125.0, 124.8, 117.4, 87.0, 30.0; HRMS-ESI (m/z): calc for C19H13N5NaO2S [M + Na]+: 398.0688, found: 398.0684.
5-(Fur-2-yl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4c). Reddish-brown power, mp 297–299 °C; IR (KBr): ν 3458, 3392, 3297, 3139, 1676, 1614 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.78 (s, 1H), 8.03–7.97 (m, 2H), 7.87–7.78 (m, 2H), 7.40 (s, 1H), 6.39 (s, 2H), 6.27–6.23 (m, 2H), 5.84 (m, 2H), 5.51 (m, 1H); 13C NMR (100 MHz, DMSO-d6) δ: 181.5, 179.8, 162.6, 162.1, 156.0, 154.3, 142.1, 140.8, 135.3, 133.6, 132.5, 130.7, 126.4, 126.2, 114.6, 110.8, 106.2, 84.5, 29.0; HRMS-ESI (m/z): calc for C19H13N5NaO3 [M + Na]+: 382.0916, found: 382.0909.
5-(3-Nitrophenyl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4d). Reddish-brown power, mp >300 °C; IR (KBr): ν 3449, 3317, 3189, 3086, 1673, 1672, 1612 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.90 (s, 1H), 8.36 (t, 1H, J = 2.0 Hz), 8.01–7.99 (m, 2H), 7.93–7.91 (m, 1H), 7.83–7.77 (m, 3H), 7.53 (t, 1H, J = 8.0 Hz), 6.37 (s, 2H), 5.90 (s, 2H), 5.52 (s, 1H); 13C NMR (100 MHz, DMSO-d6) δ: 181.6, 179.7, 162.6, 162.3, 154.2, 147.9, 147.8, 140.4, 135.3, 135.2, 133.6, 132.4, 130.8, 130.1, 126.3, 126.2, 123.1, 122.0, 117.1, 86.6, 34.8; HRMS-ESI (m/z): calc for C21H15N5NaO3 [M + Na]+: 437.0974, found: 437.0974.
5-(4-Chlorophenyl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4e). Reddish-brown power, mp 165–167 °C; IR (KBr): ν 3469, 3385, 3309, 3167, 1677, 1617 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.73 (s, 1H), 8.01–7.99 (m, 1H), 7.93–7.91 (m, 1H), 7.84, 7.75 (m, 2H), 7.42 (d, 2H, J = 8.4 Hz), 7.27 (d, 2H, J = 8.4 Hz), 6.28 (s, 2H), 5.85 (s, 2H), 5.34 (s, 1H); 13C NMR (100 MHz, DMSO-d6) δ: 181.6, 179.8, 162.6, 162.1, 154.1, 144.8, 140.0, 135.3, 133, 132.5, 131.4, 130.7, 130.3, 128.4, 126.3, 126.1, 117.8, 87.0, 34.3; HRMS-ESI (m/z): calc for C21H14N5O2 [M + Na]+: 426.0734, found: 426.0677.
5-(2,4-Dichlorophenyl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4f). Reddish-brown power, mp >300 °C; IR (KBr): ν 3520, 3465, 3398, 3338, 1666, 1643 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.89 (s, 1H), 8.02–7.99 (m, 1H), 788–7.75 (m, 3H), 7.63 (d, 1H, J = 8.4 Hz), 7.48 (d, 1H, J = 2.4 Hz), 7.35–7.32 (m, 1H), 5.92 (s, 2H), 5.82 (s, 2H), 5.51 (s, 1H); 13C NMR (100 MHz, DMSO-d6) δ: 181.4, 179.7, 162.6, 162.1, 154.0, 141.6, 140.7, 135.4, 134.0, 133.6, 132.9, 132.4, 130.6, 130.6, 129.1, 128.0, 126.3, 126.1, 116.2, 86.3, 34.5; HRMS-ESI (m/z): calc for C21H13Cl2N5NaO2 [M + Na]+: 460.0344, found: 460.0330.
5-(4-Fluorophenyl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4g). Reddish-brown power, mp 157–159 °C; IR (KBr): ν 3484, 3377, 3323, 3196, 1674, 1633 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.72 (d, 1H, J = 0.8 Hz), 8.00–7.91 (m, 2H), 7.81–7.76 (m, 2H), 7.45–7.41 (m, 2H), 7.03 (t, 2H, J = 8.8 Hz), 6.29 (s, 2H), 5.87 (s, 2H), 5.34 (s, 1H); 13C NMR (100 MHz, DMSO-d6) δ: 181.7, 179.8, 162.5, 162.0, 154.0, 142.0, 139.9, 135.3, 133.5, 132.5, 130.7, 130.3, 130.2, 126.3, 126.1, 118.1, 115.3, 115.0, 87.3, 34.1; HRMS-ESI (m/z): calc for C21H14FN5NaO2 [M + Na]+: 410.1029, found: 410.0994.
5-(2-Fluorophenyl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4h). Reddish-brown power, mp >300 °C; IR (KBr): ν 3495, 3434, 3392, 3301, 1677, 1638 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.81 (s, 1H), 8.02–8.00 (m, 1H), 7.89–7.75 (m, 3H), 7.83–7.75 (m, 2H), 7.65–7.60 (m, 1H), 7.22–7.16 (m, 1H), 7.10–7.03 (s, 2H), 5.96 (s, 2H), 5.86 (s, 1H); 13C NMR (100 MHz, DMSO-d6) δ: 181.4, 179.8, 162.5, 162.0, 159.3, 153.9, 140.6, 135.3, 133.5, 132.4, 131.9, 130.6, 129.1, 129.0, 126.3, 126.1, 124.6, 116.2, 86.3, 34.2; HRMS-ESI (m/z): calc for C21H14FN5NaO2 [M + Na]+: 410.1029, found: 410.1018.
5-(4-Methoxyphenyl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4i). Reddish-brown power, mp 196–198 °C; IR (KBr): ν 3511, 3397, 3355, 3288, 1626, 1613 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: (8.66 s, 1H), 8.00–7.89 (m, 1H), 7.93–7.91 (m, 1H), 7.83–7.74 (m, 2H), 7.31 (d, 2H, J = 8.8 Hz), 6.77 (d, 2H, J = 8.8 Hz), 6.24 (s, 2H), 5.86 (s, 2H), 5.25 (s, 1H), 3.65 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ: 181.7, 179.8, 162.4, 161.8, 158.3, 153.8, 139.5, 138.0, 135.2, 133.5, 132.5, 130.6, 139.4, 126.2, 126.1, 118.7, 113.9, 87.6, 33.9; HRMS-ESI (m/z): calc for C22H17N5NaO3 [M + Na]+: 422.1229, found: 422.1228.
5-(2,5-Dimethoxyphenyl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4j). Reddish-brown power, mp 265–266 °C; IR (KBr): ν 3465, 3385, 3310, 3175, 1669, 1646 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.64 (s, 1H), 8.03–8.01 (m, 1H), 7.88–7.76 (m, 3H), 6.94 (d, 1H, J = 8.8 Hz), 6.81 (d, 1H, J = 3.2 Hz), 6.73–6.70 (m, 1H), 6.06 (d, 2H, J = 0.8 Hz), 5.82 (s, 2H), 5.35 (s, 1H), 3.87 (s, 3H), 3.59 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ: 181.4, 180.0, 162.4, 161.8, 154.4, 153.6, 149.7, 140.7, 135.8, 135.2, 133.5, 132.5, 130.8, 126.3, 126.0, 117.7, 116.5, 113.8, 112.3, 87.5, 57.6, 55.6, 29.9; HRMS-ESI (m/z): calc for C23H19N5NaO4 [M + Na]+: 430.1515, found: 430.1508.
5-(3,4,5-Trimethoxyphenyl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4k). Reddish-brown power, mp 276–278 °C; IR (KBr): ν 3590, 3450, 3351, 3123, 1663, 1633 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.63 (s, 1H), 8.01–7.93 (m, 2H), 7.84–7.75 (m, 2H), 6.73 (s, 2H), 6.26 (s, 2H), 5.82 (s, 2H), 5.22 (s, 1H), 3.68 (s, 6H), 3.57 (s, 3H), 13C NMR (100 MHz, DMSO-d6) δ: 181.8, 179.9, 162.5, 162.0, 154.0, 152.9, 141.6, 139.8, 136.6, 135.2, 133.5132.5, 130.8, 126.3, 126.2, 118.1, 106.0, 87.4, 60.3, 56.3, 35.3; HRMS-ESI (m/z): calc for C24H21N5NaO5 [M + Na]+: 482.1440, found: 482.1362.
5-(3-Bromo-4-methoxyphenyl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4l). Reddish-brown power, mp 234–236 °C; IR (KBr): ν 3459, 3360, 3326, 3092, 1666, 1633 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.79 (s, 1H), 7.95–7.88 (m, 2H), 7.78–7.69 (m, 2H), 7.64 (d, 1H, J = 1.2 Hz), 7.31–7.29 (m, 1H), 6.94 (d, 1H, J = 8.8 Hz), 6.34 (s, 2H), 5.92 (s, 2H), 5.26 (1H), 3.73 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ: 181.7, 179.8, 162.5, 162.0, 154.3, 154.0, 139.7, 139.6, 135.2, 133.5, 132.7, 130.6, 128.1, 126.2, 126.1, 118.0, 112.9, 110.5, 87.1, 56.5, 33.8; HRMS-ESI (m/z): calc for C22H16N5NaO3 [M + Na]+: 500.0334, found: 500.0220.
5-Butyl-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4m). Reddish-brown power, mp >300 °C; IR (KBr): ν 3466, 3397, 3327, 3200, 1676, 1621 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.36 (s, 1H), 8.02–7.99 (m, 2H), 7.87–7.79 (m, 2H), 6.34 (s, 2H), 5.75 (s, 2H), 4.29 (t, 1H, J = 4.8 Hz), 1.57–1.43 (m, 2H), 1.14–1.03 (m, 3H), 0.94–0.88 (s, 1H), 0.74 (t, 3H, J = 6.8 Hz); 13C NMR (100 MHz, DMSO-d6) δ: 182.1, 179.7, 162.6, 161.8, 155.0, 141.3, 135.2, 133.4, 132.7, 130.7, 126.2, 118.0, 85.9, 34.7, 29.1, 23.1, 14.5; HRMS-ESI (m/z): calc for C19H19N5NaO2 [M + Na]+: 372.1436, found: 372.1426.
5-Amyl-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4n). Reddish-brown power, mp >300 °C; IR (KBr): ν 3468, 3403, 3327, 3201, 1676, 1620 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.37 (s, 1H), 8.00–7.98 (m, 2H), 7.85–7.75 (m, 2H), 6.38 (s, 2H), 5.78 (s, 2H), 4.28 (t, 1H, J = 4.4 Hz), 1.53–1.46 (m, 2H), 1.19–1.09 (m, 5H), 0.89–0.82 (m, 1H), 0.72 (t, 3H, J = 6.8 Hz); 13C NMR (100 MHz, DMSO-d6) δ: 182.1, 179.6, 162.6, 161.8, 155.0, 141.3, 135.2, 133.4, 132.7, 130.7, 126.2, 118.0, 85.9, 34.8, 29.1, 24.3, 22.5, 14.3; HRMS-ESI (m/z): calc for C19H19N5NaO2 [M + Na]+: 386.1593, found: 386.1564.
5-(3-Hydroxyphenyl)-5,12-dihydro-2,4-amino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4o). Reddish-brown power, mp 292–293 °C; IR (KBr): ν 3495, 3354, 3215, 3095, 1673, 1607 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 9.22 (s, 1H), 8.69 (s, 1H), 8.00–7.92 (m, 2H), 7.83–7.74 (m, 2H), 6.99 (t, 1H, J = 8.0 Hz), 6.85 (d, 1H, J = 7.6 Hz), 6.76 (s, 1H), 6.52–6.50 (s, 1H), 6.21 (s, 2H), 5.84 (s, 2H), 5.24 (s, 1H); 13C NMR (100 MHz, DMSO-d6) δ: 181.7, 179.9, 162.6, 162.0, 157.6, 154.1, 147.1, 139.8, 135.3, 133.5, 132.5, 130.6, 129.3, 126.2, 126.1, 119.3, 118.4, 115.3, 113.9, 87.3, 3.7; HRMS-ESI (m/z): calc for C21H15N5NaO3 [M + Na]+: 408.1073, found: 408.1066.
5-(2-Methylphenyl)-5,12-dihydro-2,4-diamino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4p). Reddish-brown power, mp 173–175 °C; IR (KBr): ν 3478, 3375, 3326, 3181, 1672, 1635 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 8.81 (s, 1H), 7.99 (t, 1H, J = 7.6 Hz), 7.87 (t, 1H, J = 6.4 Hz), 7.82–7.74 (m, 2H), 7.29 (t, 1H, J = 7.2 Hz), 7.07–7.01 (m, 3H), 5.87 (s, 2H), 5.62 (s, 2H), 5.31 (s, 1H), 2.63 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ: 181.8, 179.9, 169.2, 162.8, 161.8, 153.9, 144.7, 139.9, 135.3, 133.5, 132.5, 128.5, 132.2, 132.0, 126.8, 126.3, 126.1, 118.7, 88.5, 33.3, 19.9; HRMS-ESI (m/z): calc for C22H17N5NaO2 [M + Na]+: 406.1280, found: 406.1262.
2-Methylthio-5-(4-chlorophenyl)-5,12-dihydro-4-amino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4q). Reddish-brown power, mp 157–159 °C; IR (KBr): ν 3390, 3297, 3196, 1688, 1637 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 10.53 (s, 1H), 8.51 (d, 1H, J = 8.0 Hz), 7.98–7.96 (m, 1H), 7.84–7.79 (m, 1H), 7.66 (t, 1H, J = 7.6 Hz), 7.40 (d, 1H, J = 8.4 Hz), 7.28 (d, 2H, J = 8.2 Hz), 6.97 (s, 2H), 5.31 (s, 1H), 2.46 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ: 179.4, 176.0, 168.5, 161.5, 153.7, 146.3, 143.9, 135.1, 131.7, 131.6, 131.1, 130.2, 129.5, 129.0, 128.5, 125.2, 113.7, 93.3, 33.6, 13.6; HRMS-ESI (m/z): calc for C22H15ClN4NaO2S [M + Na]+: 398.0688, found: 398.0684.
2-Methylthio-5-phenyl-5,12-dihydro-4-amino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4r). Reddish-brown power, mp 157–159 °C; IR (KBr): ν 3455, 3291, 3160, 3082, 1689, 1606 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 10.51 (s, 1H), 8.51 (d, 1H, J = 7.6 Hz), 7.98–7.96 (m, 1H), 7.83–7.79 (m, 1H), 7.67–7.61 (m, 1H), 7.40 (t, 2H, J = 1.2 Hz), 7.21 (t, 2H, J = 7.2 Hz), 7.14–7.10 (s, 1H), 6.94 (s, 2H), 5.29 (s, 1H), 2.46 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ: 179.5, 176.1, 168.3, 161.6, 153.7, 146.3, 145.0, 135.2, 131.6, 131.1, 130.3, 129.0, 128.6, 128.3, 127.0, 125.2, 114.1, 93.8, 34.1, 13.6; HRMS-ESI (m/z): calc for C22H16N4NaO2S [M + Na]+: 423.0892, found: 423.0887.
2-Methylthio-5-(3-bromo-4-methoxyphenyl)-5,12-dihydro-4-amino-benzo[g]pyrimido[4,5-b]quinoline-6,11-dione (4s). Reddish-brown power, mp 157–159 °C; IR (KBr): ν 3462, 3373, 3304, 3209, 1690, 1600 cm−1; 1H NMR (400 MHz, DMSO-d6) δ: 10.49 (s, 1H), 8.50 (d, 1H, J = 7.6 Hz), 7.97 (d, 1H, J = 7.6 Hz), 7.83–7.79 (m, 1H), 7.67–7.65 (m, 2H), 7.27–7.25 (m, 1H), 6.96 (d, 3H, J = 8.4 Hz), 5.23 (s, 1H), 3.74 (s, 3H), 2.47 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ: 179.4, 176.1, 168.5, 161.5, 154.4, 153.6, 146.1, 138.7, 135.2, 132.8, 131.6, 131.1, 130.2, 129.0, 128.6, 125.2, 113.9, 113.0, 110.4, 93.4, 56.6, 33.1, 13.6; HRMS-ESI (m/z): calc for C23H17BrN4NaO3S [M + Na]+: 531.0102, found: 531.0094.
Anti-proliferative assay
SGC7901, HepG2 and L02 cells were obtained from the Cell Center of the Chinese Academy of Sciences (Shanghai, China). All cells were cultured in Dulbecco's modified eagle's media (DMEM, gibco, USA) containing 1% penicillin–streptomycin, supplemented with 10% fetal bovine serum (FBS, gibco, USA) at 37 °C, 5% CO2. Cells (3 × 103 cells) were seeded into 96-well plates and incubated at 37 °C in 5% CO2/95% air condition. Serially two fold diluted test compound solutions of each drug were added 24 h later, and the cells were incubated for the next 48 h. The final concentrations of compounds in the sample wells ranged from 0.103 μM to 50 μM. After 48 h, 20 mL 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT, 5 mg mL−1) was added to each well and the cells were incubated for an additional 4 h. Then, 100 μL DMSO were added into each well for dissolving the intracellular formazan crystals. Optical density at 570 nm of each plate was measured with a tunable microplate reader. Each group was in triplicate samples and each drug was divided into at least 5 concentrations. The percentage of absorbance from the sample-treated cells compared to that of the vehicle control (treated with DMSO) was calculated. The resulting cytotoxic activities were expressed as IC50 values and IC50 values were determined by analysis software (Graphpad Prism 6).
Acknowledgements
We are pleased to acknowledge the financial support from Xinxiang Medical University.
References
- A. Domling, Chem. Rev., 2006, 106, 17 CrossRef PubMed.
-
(a) J. Benites, J. A. Valderrama, K. Bettega, R. C. Pedrosa, P. B. Calderon and J. Verrax, Eur. J. Med. Chem., 2010, 45, 605 CrossRef PubMed;
(b) M. K. Hadden, S. A. Hill, J. Davenport, R. L. Matts and B. S. Blagg, Bioorg. Med. Chem., 2009, 17, 634 CrossRef CAS PubMed;
(c) O. A. Zakharova, L. I. Goryunov, N. M. Troshkova, L. P. Ovchinnikova, V. D. Shteingarts and G. A. Nevinsky, Eur. J. Med. Chem., 2010, 45, 270 CrossRef CAS PubMed.
- P. K. Sahu, P. K. Sahu, S. K. Gupta, D. Thavaselvam and D. D. Agarwal, Eur. J. Med. Chem., 2006, 41, 773 CrossRef PubMed.
- S. T. Huang, H. S. Kuo, C. L. Hsiao and Y. L. Lin, Bioorg. Med. Chem., 2002, 10, 1947 CrossRef CAS PubMed.
- Y. R. Jin, C. K. Ryu, C. K. Moon, M. R. Cho and Y. P. Yun, Pharmacology, 2004, 70, 195 CrossRef CAS PubMed.
- K. Sasaki, H. Abe and F. Yoshizaki, Biol. Pharm. Bull., 2002, 25, 669 CAS.
- E. V. M. dos Santos, J. W. D. M. Carneiro and V. F. Ferreira, Bioorg. Med. Chem., 2004, 12, 87 CrossRef CAS PubMed.
- D. Y. Yuk, C. K. Ryu, J. T. Hong, K. H. Chung, W. S. Kang, Y. Kim, H. S. Yoo, M. K. Lee, C. K. Lee and Y. P. Yun, Biochem. Pharmacol., 2000, 60, 1001 CrossRef CAS PubMed.
- L. J. Huang, F. C. Chang, K. H. Lee, J. P. Wang, C. M. Teng and S. C. Kuo, Bioorg. Med. Chem., 1998, 6, 2261 CrossRef CAS PubMed.
- G. H. Chae, G. Y. Song, Y. Kim, H. Cho, D. E. Sok and B. Z. Ahn, Arch. Pharmacal Res., 1999, 22, 507 CrossRef CAS.
-
(a) E. J. Lee, H. J. Lee, H. J. Park, H. Y. Min, M. E. Suh, H. J. Chung and S. K. Lee, Bioorg. Med. Chem. Lett., 2004, 14, 5175 CrossRef CAS PubMed;
(b) H. J. Lee, S. Y. Park, J. S. Kim, H. M. Song, M. E. Suh and C. O. Lee, Bioorg. Med. Chem., 2003, 11, 4791 CrossRef CAS PubMed.
- A.-R. B. A. El-Gazzar and H. N. Hafez, Bioorg. Med. Chem. Lett., 2009, 19, 3392 CrossRef CAS PubMed.
- S. P. Satasia, P. N. Kalaria and D. K. Raval, Org. Biomol. Chem., 2014, 12, 1751 CAS.
- A. M. Hayallah and M. K. D. Abdel-Hamid, Pharma Chem., 2014, 6, 45 Search PubMed.
- A. Gangjee, O. A. Namjoshi, S. Raghavan, S. F. Queener, R. L. Kisliuk and V. Cody, J. Med. Chem., 2013, 56, 4422 CrossRef CAS PubMed.
- T. A. Farghaly and H. M. E. Hassaneen, Arch. Pharmacal Res., 2013, 36, 564 CrossRef CAS PubMed.
-
(a) M. M. Gineinah, M. N. A. Nasr, S. M. I. Badr and W. M. El-Husseiny, Med. Chem. Res., 2013, 22, 3943 CrossRef CAS;
(b) R. Edupuganti, Q. Wang, C. D. J. Tavares, C. A. Chitjian, J. L. Bachman, P. Ren, E. V. Anslyn and K. N. Dalby, Bioorg. Med. Chem., 2014, 22, 4910 CrossRef CAS PubMed;
(c) F. Han, S. Lin, P. Liu, J. Tao, C. Yi and H. Xu, Bioorg. Med. Chem. Lett., 2014, 24, 4538 CrossRef CAS PubMed;
(d) R. P. de la Bellacasa, G. Roue, P. Balsas, P. Perez-Galan, J. Teixido, D. Colomer and J. I. Borrell, Eur. J. Med. Chem., 2014, 86, 664 CrossRef PubMed.
- K. Nepali, S. Sharma, M. Sharma, P. M. S. Bedi and K. L. Dhar, Eur. J. Med. Chem., 2014, 77, 422 CrossRef CAS PubMed.
Footnote |
† Electronic supplementary information (ESI) available. See DOI: 10.1039/c6ra17032c |
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