Phase-transfer catalyzed alkylation of pyrazoles and 1,2,4-triazole with cis- and trans-1,4-dichloro-2-butenes

The phase-transfer catalyzed (PTC) alkylation of pyrazoles and 1,2,4-triazole with cis- and trans-1,4-dichloro-2-butenes (DCB) has been examined. The monoalkylation products of pyrazoles with cis-DCB are bicyclic salts formed by intramolecular cyclization of the intermediate cis-1-(4-chloro-2-butenyl)pyrazoles. The corresponding trans-compounds are incapable of cyclization, but on prolonged standing they undergo intermolecular polyquaternization. Both cis- and trans-DCB undergo phase-transfer catalyzed reaction with 1,2,4-triazole to give polymeric quaternary salts. Conditions have been worked out for the dehydrochlorination of 1-(4-chloro-2-butenyl)azoles to 1-(butadien-2-yl)azoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 497–503, April, 1989.