| abstract |
The invention provides a process for the preparation of compounds of formula (I) wherein R?1, R2, R3, R4 and R5¿ are as defined in the specification; and wherein any functional groups are optionally protected; and salts thereof; which process includes the step of reacting the intermediate formed by heating a compound of formula (II), in an inert solvent, with a compound of the formula S=C(R3)R4 wherein R?1, R2, R3, R4 and R5¿ are as defined in the specification and functional groups are optionally protected; and thereinafter, if necessary, removing any protecting groups. The compounds of the formula (I) are useful as intermediates in the preparation of penems and may possess antibacterial properties and/or inhibit β-lactamase in their own right. |