Collect. Czech. Chem. Commun.
1986, 51, 2002-2012
https://doi.org/10.1135/cccc19862002
A study of photocyclization of O-alkyl N-(3-chloro-2-benzo[b]thienocarbonyl)monothiocarbamates
Peter Kutschy, Ján Imrich, Juraj Bernát, Pavol Kristian and Iveta Fedoriková
Department of Organic Chemistry and Biochemistry, Faculty of Natural Sciences, Šafárik University, Moyzesova 11, 041 67 Košice
Abstract
The O-alkyl N-(3-chloro-2-benzo[b]thienocarbonyl)monothiocarbamates prepared by the reaction of 2-isothiocyanatocarbonyl-3-chlorobenzo[b]thiophene with methanol, ethanol, 1-propanol, and 2-propanol are cyclized on irradiation with light of the wavelength above 300 nm to give high yields (80-90%) of 2-alkoxy-4H-benzo[b]thieno[2,3-e]-1,3-thiazin-4-one derivatives. From the absorption and emission spectra of the starting compounds as well as from a study of model compounds and influence of the reaction conditions it is presumed that the investigated intramolecular photosubstitution of chlorine by sulphur proceeds from the first singlet excited state (π, π*) by a radical mechanism through the phase of radical complex formation.
