SYNTHESIS AND STEREOISOMERISM OF DERIVATIVES OF <i>tert</i>-BUTYL 7-ALKYLIDENECEPH-3-EM-4-CARBOXYLATE
DOI:
https://doi.org/10.1007/7046Keywords:
tert-butyl esters of 7Z-acetylmethylidene-3-methylceph-3-em-4-carboxylic acid and 3-acetoxymethyl-7Z-(3-trimethylsylylpropyn-2-ylidene)ceph-3-em-4-carboxylic acid, 1(S)-, 1(R)-sulfoxides and sulfones of tert-butyl esters of 7Z-acetylmethylidene-3-methylceph-3-em-4-carboxylic acid and 3-acetoxymethyl-7Z-(3-trimethylsylylpropyn-2-ylidene)ceph-3-em-4-carboxylic acid, X-ray crystallography, 1H NMR spectroscopyAbstract
By condensation of tert-butyl 3-methyl-7-oxoceph-3-em-4-carboxylate and its 3-acetoxymethyl analog with acetylmethylenetriphenylphosphorane and 3-trimethylsilylpropyn-2-ylindenetriphenylphosphorane tert-butyl 7Z-acetylmethylene-3-methylceph-3-em-4-carboxylate and also 7Z- and 7E-isomers of tert-butyl 3-acetoxymethyl-7-(3-trimethylsilylpropyn-2-ylidene)ceph-3-em-4-carboxylates were synthesized. Oxidation of these compounds with 1 equivalent of meta-chloroperbenzoic acid gave their 1R- and 1S-sulfoxides, and oxidation with 2 equivalents gave the corresponding sulfones. According to data from 1H NMR spectroscopy, the carbonyl of the β-lactam descreens proton H-9 of the alkylidene group in the 7Z-isomers more strongly than in the 7E-isomers, shifting their signals to weaker field. Analogous shifts of the H-6 signal to weaker field was observed in the 1R-sulfoxides in comparison with that for the 1S-sulfoxide. These results were confirmed by X-ray crystallography of tert-butyl 7Z-acetylmethylene-3-methyl-1S-oxoceph-3-em-4-carboxylate and tert-butyl 7Z-acetylmethylene-3-methyl-1,1-dioxoceph-3-em-4-carboxylate.
How to Cite
Vorona, M.; Veinberg, G.; Belyakov, S.; Petrova, M.; Liepinsh, E.; Lukevics, E. Chem. Heterocycl. Compd. 2008, 44, 486. [Khim. Geterotsikl. Soedin. 2008,618 .]
For this article in the English edition see DOI 10.1007/s10593-008-0067-8
