PROCESS FOR PRODUCING DERIVATIVES OF CEPHALOSORIN OR THEIR ESTERS, ETHERS, OR SALTS, OR THEIR HYDRATES, OR ESTER HYDRATES, ETHER HYDRATES, OR SALTS

摘要

Acyl derivatives of the formula wherein R signifies hydrogen or a protective group which can be split off, R1 signifies lower alkyl and X signifies the group +TR wherein one of the residues R2 and R3 represents hydrogen and the other represents alkyl and R4 represents lower alkyl the easily hydrolyzable esters and ethers thereof, the salts and hydrates of the above compounds, esters, ethers and salts.