Carbon Dioxide → HCID 20366961, compound

Participants

Reaction Conditions

Reaction Steps

Ethyl 3-(2-chlorophenyl)-carbazate (15.2 g.) is added to a 14.8% (w/v) solution (71 cc.) of phosgene in toluene. The solution obtained is then heated gradually until gas ceased to be evolved, whilst condensing the condensable vapours by means of a condenser containing solid carbon dioxide. The temperature of the reaction mixture is then 105° C. The condenser containing solid carbon dioxide is replaced by a coil condenser and the mixture is heated under reflux until the evolution of gas is complete. After cooling, the solution is concentrated under reduced pressure (25 mm. Hg) at 50° C. The residue obtained is dissolved in methylene chloride (71 cc.), then triethylamine (9.5 cc.) is added to the solution and the mixture is stirred overnight at 20° C. Water (71 cc.) is then added in order to dissolve the precipitate of triethylamine hydrochloride. The organic phase is decanted and then washed successively with 0.1N hydrochloric acid (50 cc.) and water (100 cc.). After drying over sodium sulphate, the solvent is removed by evaporation under reduced pressure (25 mm.Hg) at 40° C. The residual solid is recrystallised from petroleum ether, b.p. 35°-60° C., (380 cc.) to give 3-(2-chlorophenyl)-5-ethoxy-1,3,4-oxadiazolin-2-one (13.7 g.), melting at 45° C.

Provenance & Evidence