Collect. Czech. Chem. Commun. 1983, 48, 3421-3425

Synthesis and stability of 2-oxoisothiocyanates

Vladimír Bobošíka, Anna Piklerováa and Augustin Martvoňb

a Department of Organic Chemistry, Slovak Institute of Technology, 812 37 Bratislava
b Research Institute for Drugs, 801 00 Bratislava


Enolizable 2-oxoisothiocyanates Ia-If were prepared from hydrochlorides of amino ketones, containing a hydrogen atom in the α-position, by reaction with thiophosgene in the presence of CaCO3. At room temperature the enol form of these compounds undergoes slow cyclization to give the isomeric 4-oxazoline-2-thiones IIb-IIf. In the presence of bases this isomerization proceeds rapidly even at room temperature. 2-Isothiocyanatocyclopentanone (Ia) does not cyclize to the corresponding oxazolinethione either on heating or action of bases. The rate of the thermally initiated isomerization of the 2-oxoisothiocyanates Ib-If was determined by IR spectroscopy.