| abstract |
A new process for preparing 3-methylenecepham compounds of the formula: ##STR1## wherein R 1 is amino or a protected amino group, and n R 2 is a carboxy or a protected carboxy group, n or a salt thereof, n which comprises reducing a compound of the formula: ##STR2## wherein R 1 and R 2 are each as defined above, and n R 3 is halogen or heterocyclicthio which may have suitable sutstituent, or a salt thereof, with a combination of a metal selected from the group consisting of zinc, tin and iron, and an ammonium salt of an acid selected from the group consisting of ammonium halide, ammonium carbonate and ammonium acetate, said 3-methylenecepham compounds being useful as intermediates for preparing antimicrobially active 3-cephem compounds. |