205. Preparation of 3-substituted oxazolid-2,4-diones by cyclisation of N-substituted N-chloroacylcarbamates

Abstract

Substituted oxazolid-2,4-diones have been prepared from N-substituted carbarnates and a-chloroacyl chlorides. The intermediate N-substituted chloroacylcarbamates cyclise at higher temperatures t o t h e diones. The plots of t h e cyclisation rates of ethyl N-alkyl-N-chloroacetylcarbamates were straight, and steric effects influenced the cyclisation. Infrared spectra of t h e N-substituted chloroacylcarbamates and of 3-substituted oxazolid-2,4-diones are discussed.%SUBSTITUTED oxazolid-2,4-diones (111) are an important class, as several members possess analgesic and anti-epileptic properties. 3-Alkyl derivatives have been prepared by alkylation of oxazolid-2,4-dione 193-5 or by treatment of a-hydroxy-esters with alkyl isocyanates and cyclisation of the resulting urethanes, by which method also the 3-aryl derivatives have been synthesised. 6 We found that a convenient preparation of 3-alkyl-and 3-aryl-oxazolid-2,4-diones was to heat at >180" lower alkyl alkyl-or aryl-carbarnates (I) with an a-chloroacyl chloride, according to the scheme shown.

Analyse par chromatographie en phase gazeuse de l'urethane dans les vins (1)

“…L'absorption caractéristique du carbonyle de l'ester, trouvée à 5,9 y-pour l'uréthane, se présente à 5,6 ypour le dérivé. Ceci est qualitativement en accord avec les spectres de l'uréthane et du dérivé N-chloroacétylé publiés par d'autres auteurs (PIANKA et POLTON, 1960). En outre le dérivé possède une bande à 6,54 y-, absent pour l'uréthane, d'intensité presque égale à l'absorption du car¬ bonyle.…”

One-Pot, Three-Step Preparation of Alkyl and Aryl Alkylcarbamates from S-Methyl N-Alkylthiocarbamates

“…Yields of the virtually pure (TLC, 1 H NMR) crude compounds are listed in Table 1; physical and spectral data are given below. 17, 55 (26), 43 (21), 41 (17).…”

Preparation of carbon‐14 labelled mecarbam (O,O‐DI‐[1‐14c]‐ethyl s‐[N‐ethoxycarbonyl‐N‐methylcarbamoylmethyl] phosphorothiolothionate)

“…We found that the solid product formed in this way could be EXPERIMENTAL 14 [l-C ] -Ethanol was supplied by The Radiochemical Centre, Amersham, U.K., and ethyl N-chloroacetyl-N-methylcarbamate (6) by Cheminova AS, Lemvig , Denmark.…”