Penicillin derivatives

摘要

This invention provides a penicillin derivative of the formula and a salt thereof <IMAGE> (I) wherein X represents chlorine atom or bromine atom and R represents hydrogen atom or penicillin carboxy-protecting radical, and a process for preparing the derivative of the formula (I) and a salt thereof by reacting a compound of the formula <IMAGE> wherein R is as defined above with a chlorinating reagent or brominating reagent and, when required, forming a salt thereof.