One-Pot Three-Component Synthesis of 2-Imino-1,3-Thiazolines on Soluble Ionic Liquid Support.
An efficient one-pot, three-component synthesis of 2-imino-1,3-thiazolidines and 2-imino-1,3-thiazolines using ionic liquid-tethered 2-aminobenzimidazoles was reported. The protocol includes reaction of ionic liquid attached 2-aminobenzimidazoles with isothiocyanates to afford isothioureas, followed by its base induced inter and intramolecular nucleophilic displacement reactions with 1,2-dichloroethane (EDC) which results in thiazolidine ring formation. In the next to the last step, the ionic liquid support was removed by methanolysis to deliver 2-imino-1,3-thiazolidines, which were sequentially oxidized with manganese(III) triacetate to yield 2-imino-1,3-thiazolines. The salient feature of this method is the use of 1,2-dichloroethane as a synthetic equivalent for α-haloketone to avoid the use of toxic halogenating reagents.
Department of Applied Chemistry, National Chiao-Tung University , Hsinchu 300-10, Taiwan.
Chan-Yu
CY
Chen
Department of Applied Chemistry, National Chiao-Tung University , Hsinchu 300-10, Taiwan.
Indrajeet J
IJ
Barve
Department of Applied Chemistry, National Chiao-Tung University , Hsinchu 300-10, Taiwan.|Department of Medicinal and Applied Chemistry, Kaohsiung Medical University , 100, Shih-Chuan First Road, Kaohsiung, 80708, Taiwan.
Chung-Ming
CM
Sun
D001562:Benzimidazoles / Q000737:chemistry; D005025:Ethylene Dichlorides / Q000737:chemistry; D007097:Imines / Q000138:chemical synthesis*; D052578:Ionic Liquids / Q000737:chemistry*; D017879:Isothiocyanates / Q000737:chemistry; D015394:Molecular Structure; D013844:Thiazoles / Q000138:chemical synthesis*; D013890:Thiourea / Q000737:chemistry
C507683:2-imino-1,3-thiazoline; D001562:Benzimidazoles; D005025:Ethylene Dichlorides; D007097:Imines; D052578:Ionic Liquids; D017879:Isothiocyanates; D013844:Thiazoles; C037152:isothiocyanic acid; C024565:ethylene dichloride; C027391:2-aminobenzimidazole; D013890:Thiourea
1,2-dichloroethane; 2-imino-1,3-thiazolines; ionic liquid support; one pot