| abstract |
Process for preparing intermediary products of cephalosporine having the formula (I) wherein R1 is an acyl group. Modification of a compound having the formula (IV) and/or (IVa) wherein R1 has the same meaning as hereabove and (A), respectively (B) represents a heterocycle having 5 or 6 atoms, and comprising in addition to the N atom one or two other heteroatoms, for example O, N and S, and susceptible of being substituted or ringed with an optionally substituted benzol cycle, with a compound of formula (V) wherein R10 represents hydrogen or an amino protection group. |