Process for preparing ceftaroline salts or hydrates thereof

A process for the preparation of a ceftaroline salt or a hydrate thereof, wherein the process comprises the steps of:

• (a) treating a compound of Formula III
• or an ester derivative or salt thereof with a compound of Formula IV
• or a salt or reactive derivative thereof to obtain a reaction mass;
• and
• (b) treating the reaction mass with a salt-forming agent to obtain a ceftaroline salt or a hydrate thereof.