Cyclization of Active Methylene Isocyanides with α-Oxodithioesters Induced by Base: An Expedient Synthesis of 4-Methylthio/Ethoxycarbonyl-5-acylthiazoles
作者:Toreshettahally R. Swaroop、Kanchugarakoppal S. Rangappa、Maralinganadoddi P. Sadashiva、Kuppalli R. Kiran、Narasimhamurthy Rajeev、Seegehalli M. Anil
DOI:10.1055/s-0039-1690821
日期:2020.5
Cyclization of tosylmethylisocyanide with α-oxodithioesters in the presence of KOH is reported for the synthesis of 4-methylthio-5-acylthiazoles. Similarly, ethyl isocyanoacetate underwent cyclization with α-oxodithioesters to form 4-ethoxycarbonyl-5-acylthiazoles in the presence of DBU/EtOH. Mechanisms for the formation of thiazoles are proposed. These thiazoles can also be obtained by Takeda reaction
Acid-Catalyzed Condensation of o-Phenylenediammines and o-Aminophenols with α-Oxodithioesters: A Divergent and Regioselective Synthesis of 2-Methylthio-3-aryl/Heteroarylquinoxalines and 2-Acylbenzoxazoles
作者:Kuppalli R Kiran、Toreshettahally R Swaroop、Kodipura P Sukrutha、Jeegundipattana B Shruthi、Seegehally M Anil、Kanchugarakoppal S Rangappa、Maralinganadoddi P Sadashiva
DOI:10.1055/s-0039-1690616
日期:2019.11
Abstract o-Phenylenediammines and o-aminophenols were reacted with α-oxodithioesters in a highly regioselective fashion to give 2-methylthio-3-aryl/heteroarylquinoxalines and 2-acylbenzoxazoles in 55–94% and 45–86%, respectively, in the presence of p-toluene sulfonic acid catalyst. Control experiments involving reaction of aniline with a α-oxodithioester indicated that the thiocarbonyl group is more