Synthesis of 2,3,4,5-tetradehydrobiotin esters

Abstract

1. The alkaline hydrolysis of the ethyl ester of N,N′-diacetyl-α-keto-α′-mercaptodehydrodesthiobiotin gives α-keto-α′-mercaptodehydrodesthiobiotin, which when heated with alkyl iodides or iodine in alcohol is esterified with a retention of the free mercapto group. 2. Esters of 2,3,4,5-tetradehydrobiotin are obtained when the esters of α-keto-α′-mercaptodehydrodesthiobiotin are heated or when the ethyl ester of N,N′-diacetyl-α-keto-α′-mercaptodehydrodesthiobiotin is treated with boron trifluoride etherate.