Synthesis of 6-amino-2,3-dihydropyridine-4-thiones via novel efficient thioenolate-carbodiimide rearrangement

摘要

Anew and efficient method for the synthesis of 6-amino-2,3-dihydro-4-pyridinethiones from N-(3-butenyl)thioureas, without the use of conventional thiophosphorus reagents has been reported. Thioureas are initially transformed into iodocyclothiocarbamates which subsequently give cyclic thioenol esters after base-mediated HI elimination. These esters readily undergo a base-mediated (tBuOK) thioenolate-carbodiimide rearrangement, accompanied by C-S bond cleavage and C-C bond formation, to finally give a series of novel 6-amino-2,3-dihydropyridine-4-thiones. (C) 2016 Elsevier Ltd. All rights reserved.