| abstract |
Process for preparation of halomethyl esters (and related esters) of penicillanic acid 1,1-dioxide of the formula <IMAGE> (I) where X is Cl, Br, I, certain alkylsulfonyloxy or arylsulfonyloxy groups, useful as intermediates in production of antibiotics having beta-lactamase activity, which comprises hydrogenolysis of an ester of the formula <IMAGE> (VI) where n is zero, 1 or 2; Y and Z are each Cl, Br or I, or Y is H and Z is Cl, Br, I, C 3BOND N- or SCN-, or Y is arylselenyl and Z is Cl or Br; and when n is zero or 1, oxidation of the hydrogenolysis product; a process for preparing compounds of formula (VI, n=2) by oxidation of the corresponding compound (VI) wherein n is zero or 1, and certain novel intermediates useful in the above processes. |