(Chlorothio)formyl chloride → Phenyl-3H-1,2,4-dithiazol-3-one

Participants

Reaction Conditions

Reaction Steps

All the glassware were dried in the preheated oven prior to the reaction for two hours at 200° C. A 500 ml three neck round bottom flask was equipped with magnetic bar, thermometer, pressure equalizing funnel and a positive inflow of argon. The assembly was placed on to the magnetic stirrer having ice bath. Chlorocarbonyl sulfenyl chloride (9.55 grams, 72.87 mmol) was transferred to the reaction flask. 100 ml of CH3CN was also added to the flask. The mixture was cooled down to 10° C. Thiobenzamide (10 grams, 72.87 mmol) was dissolved in a separate flask using 80 ml of CH3CN and diisopropylethylamine (18.84 gm, 145.76 mmol). This solution was transferred to the pressure equalizing funnel. The thiobenzamide solution was added slowly to the reaction flask. The temperature of the flask raised to 12-15° C. The mixture was stirred for 30 min. at 5-10° C. The disappearance of the starting material and formation of two isomeric nonpolar spots was observed on TLC. The reaction mixture was filtered through a sintered funnel. The filtrate was rotaevaporated to dryness and left on high vacuum for two hours. The solid was crystallized with a mixture of hexanes and ethyl acetate in a ratio of 95:5, respectively. The upper nonpolar spot on the TLC was left behind in the mother liquor and characterized as 3,5-diphenyl-1,2,4-thiadiazole. The crystals of 3-phenyl-1,2,4-dithiazoline-5-one were light yellow in color and the recovery was 9.25 gm (65%). The yield of the crude mix was 75%. The structure of 3-phenyl-1,2,4-dithiazoline-5-one was confirmed by 1H-NMR (FIG. 1), 13C-NMR (FIG. 2), mass spectrometry (FIG. 3) and elemental analysis.

Provenance & Evidence