Esterification diphenylmethyl esters

Reaction of cyanuric chloride with three equivalents of pyridine gives 2,4,6-tripyridinio-1,3,5-triazine (TPT), a new and mild esterification agent for the preparation of penicillin and cephalosporin esters (Scheme 75) <90H(3l)2055>. This esterification procedure has been successfully applied to the industrial production of diphenylmethyl 6) -(4-toluamido)penicillate, an important intermediate for the production of Shionogi )3-lactam antiobiotics Latamoxef, Flomoxef, and Ceftibuten. The use of cyanuric chloride with pyridine is safer and more economical on a large scale, with better product yield than other known esterification procedures. 

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