Optimizing thiadiazole analogues of resveratrol versus three chemopreventive targets
摘要:
Chemoprevention is an approach to decrease cancer morbidity and mortality through inhibition of carcinogenesis and prevention of disease progression. Although the trans stilbene derivative resveratrol has chemopreventive properties, its action is compromised by weak non-specific effects on many biological targets. Replacement of the stilbene ethylenic bridge of resveratrol with a 1,2,4-thiadiazole heterocycle and modification of the substituents on the two aromatic rings afforded potential chemopreventive agents with enhanced potencies and selectivities when evaluated as inhibitors of aromatase and NF-kappa B and inducers of quinone reductase 1 (QR1). (C) 2011 Elsevier Ltd. All rights reserved.
Eosin Y Catalyzed Visible-Light-Driven Aerobic Oxidative Cyclization of Thioamides to 1,2,4-Thiadiazoles
作者:Lal Yadav、Vishnu Srivastava、Arvind Yadav
DOI:10.1055/s-0032-1318158
日期:——
A new approach for an efficient metal-free synthesis of 1,2,4-thiadiazoles from primary thioamides using visible light and air in the presence of eosin Y as a photoredox catalyst is reported. The protocol involves an aerobic oxidative cyclization of thioamides via the formation of C–N and C–S bonds to afford excellent yields of the products in a simple one-pot operation under mild conditions.
报道了一种在曙红 Y 作为光氧化还原催化剂的情况下,使用可见光和空气从伯硫代酰胺高效无金属合成 1,2,4-噻二唑的新方法。该方案涉及通过形成 C-N 和 C-S 键对硫代酰胺进行有氧氧化环化,以在温和条件下的简单一锅操作中提供优异的产品收率。
Steric and Electronic Factors Influence Regio-isomeric Thiazole Formations Between Substituted Benzothioamides and Ethyl Bromopyruvate
unexpected thiazole 1B formation when 2,6‐dichlorobenzothioamide 1 and ethyl bromopyruvate were reacted under basic conditions at elevated temperatures in ethanol. Thiazole 1B, regio‐isomeric to that expected under conventional Hantzsch conditions, was extensively characterized and later confirmed by single crystal X‐ray structure. We carried out this transformation with several substituted benzothioamides and
A Mild and Efficient Synthesis of 2-Oxazolines via Transamidation–Cyclodehydrosulfurisation of Thioamides with 2-Aminoethanol
作者:Uma Pathak、D. Goud
DOI:10.1055/s-0032-1317341
日期:——
Transamidation of thioamides with 2-aminoethanol, followed by cyclodehydrosulfurisation of the resultant N-(beta-hydroxyethyl)thioamides, has been utilised for the mild and efficient synthesis of 2-oxazolines. The developed protocol was found to be of general applicability.
An unexpected synthesis of 3,5-diaryl-1,2,4-thiadiazoles from thiobenzamides and methyl bromocyanoacetate
作者:Abdelrahman S. Mayhoub、Evgeny Kiselev、Mark Cushman
DOI:10.1016/j.tetlet.2011.07.068
日期:2011.9
Aryl thioamides undergo very rapid condensation in the presence of methyl bromocyanoacetate to provide quantitative yields of 3,5-diaryl-1,2,4-thiadiazoles with an easy work-up and a high degree of product purity. The method can be scaled up with no loss in efficiency. (C) 2011 Elsevier Ltd. All rights reserved.