Unexpected Ring Enlargement of 2-Hydrazono-2,3-dihydro-1,3-thiazoles to 1,3,4-Thiadiazines
作者:Wolf-Diethard Pfeiffer、Klaus-Dieter Ahlers、Ashot S. Saghyan、Alexander Villinger、Peter Langer
DOI:10.1002/hlca.201300077
日期:2014.1
α‐bromoacetophenone can result in the formation of isomeric 1,3,4‐thiadiazines and two different thiazoles. We studied the use of 4‐methyl‐ and 4‐ethylthiosemicarbazide as dinucleophilic building blocks. In this context, we observed an unprecedented rearrangement of a 2‐hydrazono‐2,3‐dihydrothiazole to a 1,3,4‐thiadiazine. While ring contractions of 1,3,4‐thiadiazines to thiazoles are quite common, ring enlargements