DERIVATI DI 7-OSSO-4-TIA-1-AZA-BICICLO-[3,2,0]EPTANO

This invention relates to 7-oxo-4-thia-1-aza-bicyclo-[3,2,0]-heptane derivatives, to processes for their synthesis from esters of penicillanic acid 1-oxide, and to intermediate compounds obtained in the synthesis. More particularly, the present invention relates to new and novel compounds of formula (1): (1) wherein R is a hydrogen atom, an alkyl having from 1 to 5 carbon atoms, trichloroethyl, benzyl, p-nitrobenzyl, diphenylmethyl, acetoxymethyl, pivaloyloxymethyl, phthalidyl, trimethylsilyl or a group of formula and R1 is -CH2OH, -CH2OCOR2, -CH2OR3, -COOR2, -CHO, -CH2SH, -CH2SR4, -CH2NH2, -CH2NHCOR2 in which R2 is an alkyl having from 1 to 5 carbon atoms, aryl, aralkyl or a five- or six-membered heterocyclic ring containing one or more heteroatoms; R3 is an alkyl having from 1 to 5 carbon atoms, benzyl, trityl, trialkylsilyl; and R4 is a five- or six-membered heterocyclic ring containing one or more heteroatoms, benzyl, trityl or trialkylsilyl; and to the synthesis of such compounds. Compounds of formula (1) (E+Z isomers) are endowed with antibacterial activity.