A facile synthetic approach to 3-halo-4-substituted-1,5-dihydro-4H-1,2,4-triazoline-5-thiones based on retro-Michael addition

Abstract

A facile 3-step synthetic approach to 3-halo-4-substituted-1,5-dihydro-4H-1,2,4-triazoline-5-thiones (1a—1k) from corresponding unhalogenated 8a—8i was developed based on the strategy of retro-Michael addition, with the key steps being regioselective S-alkylation of compounds 8a—8i with ethyl 3-iodopropionate(12c) and alkaline cleavage of the propionate protecting group via retro-Michael addition. The synthetic approach was characterized by simplicity of operation and wide substrate scope.

Keywords

Synthetic approach / Protecting group / Triazole / Halogenation / Regioselectivity / Retro-Michael addition

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