M. Vorona, I. Potoročina, G. Veinberg
May 1, 2007
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Journal
Chemistry of Heterocyclic Compounds
Abstract
The reaction of tert-butyl 7α-chloro-and 7-β-chloro-7α-isopropoxy-3-methyl-1,1-dioxoceph-3-em-4-carboxylates with the Vilsmeier reagent was carried out with introduction of N,N-dimethylaminomethylene group at position 2 in the E-and Z-isomeric forms. Prolonged treatment of tert-butyl 7α-chloro-3-methyl-2-(N,N-dimethylaminomethylene)-1,1-dioxoceph-3-em-4-carboxylate with hydroxylamine hydrochloride in acetonitrile at 40–50°C gave tert-butyl 10(S)-chloro-6-methyl-5-oxa-1,1,9-trioxo-1-thia-4,8-diazatricyclo[7,2,0,02,6]undecane-7(R)-carboxylate which isomerized into 1-tertbutoxycarbonylmethyl-3α-chloro-4-(5-methylisoxazole-4-sulfonyl)azetidin-2-one. In the case of tertbutyl 7β-chloro-7α-isopropoxy-3-methyl-2-(N,N-dimethylaminomethylen)-1,1-dioxoceph-3-em-4-carboxylate the analogous reaction gave tert-butyl 10β-chloro-(2S,6S,7S,10R,11R)-10α-isopropoxy-6-methyl-5-oxa-1,1,9-trioxo-1-thia-4,8-diazatricyclo[7,2,0,02,6]undecane-7(R)-carboxylate, the struc-ture of which was determined by 2D-NOESY two-dimensional spectroscopy. The compounds synthesized showed weak or no cytotoxic activity with respect to monolayers of cancer cells in vitro.