Eco-efficient, regioselective and rapid access to 4,5-disubstituted 1,2,3-thiadiazoles via [3 + 2] cycloaddition of α-enolicdithioesters with tosyl azide under solvent-free conditions
Eco-efficient, regioselective and rapid access to 4,5-disubstituted 1,2,3-thiadiazoles via [3 + 2] cycloaddition of α-enolicdithioesters with tosyl azide under solvent-free conditions
An efficient, sustainable, and regioselective one-pot synthesis of hitherto unreported 4-aroyl/hetaroyl/alkanoyl-5-alkyl/allyl/benzylsulfanyl-1,2,3-thiadiazoles has been achieved by [3 + 2] cycloaddition of α-enolicdithioesters with tosyl azide through cascade 1â2 (SâN) and 3â4 (CâN) bond connections involving Wolff-type heterocyclization. Optimally, the reactions are very fast and completed within 2â15 minutes, when a mixture of α-enolicdithioester and tosyl azide was stirred at 0 °C in the presence of Et3N under solvent-free conditions. Furthermore, no co-catalyst or activator is necessary. The eco-compatibility, mild conditions, excellent yields, easy purification, and avoidance of expensive/toxic reagents are advantages of this protocol to access this medicinally privileged substructure.
Visible light promoted synthesis of disubstituted 1,2,3-thiadiazoles
作者:Vishal SRIVASTAVA、Pravin K. SINGH、Praveen P. SINGH
DOI:10.33224/rrch.2020.65.3.01
日期:——
A novel one-pot visible light irradiated synthesis of disubstituted 1,2,3-thiadiazole from alpha-enolicdithioesters with tosyl azide have been reported. The reaction completed within 12-20 minutes, at room temperature, when a mixture of alpha-enolicdithioester and tosyl azide undergo photocatalysed reaction under solvent-free conditions. Furthermore, no co-catalyst or activator is necessary. This protocol includes eco-compatibility, mild conditions, excellent yields, easy purification, and avoidance of expensive/toxic reagents to synthesise organic compounds of medicinal importance, which fulfils the basic principle of green chemistry.