Detritylation of Protected Tetrazoles by Naphthalene-Catalyzed Lithiation

Treatment of N-tritylated tetrazoles bearing aliphatic, aromatic, or heteroaromatic substituents (including functionalized ones) with lithium powder and a catalytic amount of naphthalene led to reductive removal of the trityl group to give excellent yields of the corresponding free tetrazoles without decomposition of the tetrazole ring. The detritylation process was successfully extended to several tetrazoles that are components of sartans, an interesting class of drugs. The chemoselectivity between trityl–tetrazole and trityl­–amine bond-cleavage reactions was also studied. This method represents an efficient technique for deprotection of tritylated tetrazoles under non-acidic conditions.

This work was financially supported by the Agence Nationale pour le Développement de la Recherche en Santé (ANDRS; Algeria) and by the Department of Organic Chemistry of the University of Alicante (Spain). We are very grateful to the Spanish Ministerio de Asuntos Exteriores y de Cooperación for a cooperation grant (AP/039112/11).