Studies related to penicillins. Part XIV. Oxidations of (4R,5R)-11,11-dimethyl-4-phenoxyacetamido-6-thia-2,9,10-triazatricyclo[6.3.0.02,5]-undec-8-en-3-one

Abstract

The adduct (13)[or (16)], obtained from the reaction of 4-isopropylidene-3-oxo-7β-phenoxyacetamidocepham (1) with hydrazine, readily undergoes dehydration to give the title pyrazoline (2). N-Bromosuccinimide converts the derivative (2) into the 8-bromo-pyrazoline (6), which is transformed into the 8-methoxy-pyrazoline (7) by silver(I) perchlorate in methanol. The 8-acetoxy-pyrazoline (8), formed by the action of lead tetra-acetate on the pyrazoline (2), affords the 8-hydroxy-pyrazoline (9) in the presence of methanolic triethylamine or potassium t-butoxide in tetrahydrofuran. With potassium t-butoxide in t-butyl alcohol, it yields the epimeric alcohol (16). Compounds (7)–(9) lose nitrogen when irradiated to give the cyclopropyl derivatives (18)–(20), respectively, Iron(III) chloride converts the cyclopropanol (20) into the carbinolamine (24).

The pyrazoline (2) reacts with mercury(II) acetate in acetic acid to give the pyrazolinylazetidine diacetate (28), which slowly decomposes with loss of nitrogen to the enone (29) at room temperature.