摘要:
Disclosed is a process for preparing 2β-substituted-methylpenicillin derivative of the formula wherein R is H or carboxyl protecting group, R 1 is H or halo, R 2 is H, lower alkyl. lower alkoxy, halogen. azido, lower alkylthio, phthalimide or a group -NHR 3 (wherein R 3 is H or acyl), and - is an optionally substituted monocyclic or bicyclic heterocyclic group having 1 to 4 nitrogen atoms in the ring structure, the process comprising reacting a compound of the formula wherein X is Cl or Br, and R, R 1 and R 2 are as defined above with a heterocyclic compound of the formula