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
A preliminary investigation of Mesoionic Xanthine analogues as inhibitors of platelet aggregation
作者:Mark Hellberg、James F. Stubbins、Richard A. Glennon
DOI:10.1016/s0968-0896(00)00123-1
日期:2000.8
A series of mesoionic xanthines (e.g. mesoionic thiazolopyrimidines, 3, and thiadiazolopyrimidines, 5) and related analogues were examined as inhibitors of human platelet aggregation. Appropriately substituted compounds were found to fully inhibit platelet aggregation, and anhydro-(6-ethyl-8-isopentyl-7-oxo-5-hydroxy-1,3,4-thiadiazolo[3,2 -a]pyrimidinium hydroxide) (5b) was 40 times more potent than
copper-catalyzed coupling of oximeacetates with isothiocyanates. Various 4-substituted and 4,5-disubstituted 2-aminothiazoles were formed smoothly under mild reaction conditions. This process involved copper-catalyzed N–O bond cleavage, activation of vinyl sp2 C–H bonds, and C–S/C–N bond formations. It is noteworthy that the oximeacetates were used not only as a substrate but also as a single oxidant
Highly Efficient Heterogeneous Copper-Catalysed Coupling of Oxime Acetates with Isothiocyanates Leading to 2-Aminothiazoles
作者:Yuxin Tuo、Fang Yao、Yang Liao、Mingzhong Cai
DOI:10.3184/174751917x14894997017739
日期:2017.4
The heterogeneous coupling reaction of oxime acetates with isothiocyanates was achieved at 110 °C in toluene in air in the presence of a bidentate nitrogen-functionalised MCM-41-immobilised copper(I) complex (MCM-41-2N-CuI) with Cs2CO3 as base to afford a variety of 2-aminothiazoles in good yields. The MCM-41-2N-CuI catalyst can be easily recovered by a simplefiltration and reused at least eight times