Visible light triggered, catalyst free approach for the synthesis of thiazoles and imidazo[2,1-b]thiazoles in EtOH : H<sub>2</sub>O green medium
作者:Anu Mishra、Madhulika Srivastava、Pratibha Rai、Snehlata Yadav、Bhartendu Pati Tripathi、Jaya Singh、Jagdamba Singh
DOI:10.1039/c6ra05385h
日期:——
The development of a visible light promoted, mild and greener approach for the synthesis of highly functionalized thiazoles and imidazo[2, 1-b]thiazoles under photochemical activation in EtOH:H2O green medium is demonstrated....
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
Reactions between α-haloketones and o-carbethoxy phenyl thiourea have been discussed; a mechanism for the observed exclusive formation of 9:10-thiopega-2:10-diene-4-ones in the case of α-haloalkaryl ketones has been advanced and a number of intermediates isolated in case of chloro acetone.
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
Effect of Substituents on the Regioselectivity of the Reaction of α-Tosyloxyketones with Thioureas in Acidic Medium: Access to 2-Aminothiazoles and 2-Imino-2,3-dihydrothiazoles
作者:Ranjana Aggarwal、Rajiv Kumar、Dionisia Sanz、Rosa M. Claramunt
DOI:10.1002/jhet.1676
日期:2014.5
Regioselective condensation of α‐tosyloxyacetophenones 1 and N‐substituted thioureas 2 in acidicmedium to give regioisomers 2‐aminothiazoles I and 2‐imino‐2,3‐dihydrothiazoles II is largely influenced by the substituents present on 1 and 2. A mechanism, supported by DFT calculations has been proposed to explain the observed regioselectively.