Collect. Czech. Chem. Commun. 1979, 44, 912-917

Kinetics of cyclization of S-ethoxycarbonylmethylisothiouronium chloride to 2-imino-4-thiazolidone

Vladimír Macháček, Said A. El-bahai and Vojeslav Štěrba

Department of Organic Chemistry, Institute of Chemical Technology, 532 10 Pardubice


Kinetics of formation of 2-imino-4-thiazolidone from S-ethoxycarbonylmethylisothiouronium chloride has been studied in aqueous buffers and dilute hydrochloric acid. The reaction is subject to general base catalysis, the β value being 0.65. Its rate limiting step consists in acid-catalyzed splitting off of ethoxide ion from dipolar tetrahedral intermediate. At pH < 2 formation of this intermediate becomes rate-limiting; rate constant of its formation is 2 . 104 s-1.