Santhosh Chikkappaiahnayaka, Singh Krishna Ravi, Sheela Kalleshappa, Swaroop Toreshettahally R, Sadashiva Maralinganadoddi P
Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru 570 006, India.
Department of Studies in Organic Chemistry, University of Mysore, Manasagangotri, Mysuru 570 006, India.
J Org Chem. 2023 Aug 18;88(16):11486-11496. doi: 10.1021/acs.joc.3c00589. Epub 2023 Jul 31.
An acid-catalyzed regioselective cyclization reaction of 2,5-disubstituted-1,3,4-thiadiazoles and 1,3,4-oxadiazoles has been developed. The synthetic precursors alkyl 2-(methylthio)-2-thioxoacetates/alkyl 2-amino-2-thioxoacetates react efficiently with acyl hydrazides, which transformed into a series of dehydrative and desulfurative products with employment of -TSA and AcOH through a regioselective cyclization process. The alkyl 2-amino-2-thioxoacetate pathway generates excellent yield among the mentioned procedures. The reported methods are operationally simplistic and highly efficient with metal-free conditions and demonstrate significant functional group compatibility. Regioselective cyclized products were confirmed by single-crystal X-ray diffraction studies.
