Dimethylformamide → HCID 178516954, 화합물

To a stirred suspension of 2-(2-thienylthio) succinic acid (75.5 g, 0.325 mol) in methylene chloride (500 ml) under a nitrogen atmosphere was added dimethylformamide (3 ml) followed by the dropwise addition of oxalyl chloride (70.7 ml, 0.81 mol) over a 1/2 hour period. The mixture was stirred at ambient temperature for 21/2 hours and the resulting solution was concentrated in vacuo to a brown oil. Then 1/2 of this oil was dissolved in methylene chloride (200 ml), cooled to about -78° C. and stirred as trifluoromethane sulfonic acid (50 g, 0.33 mol) was added dropwise over 5 minutes. After 1/4 hour at -78° C., the cooling bath was removed and the temperature was allowed to rise to room temperature. After 43/4 hours, the mixture was poured into ice and water. Methylene chloride (400 ml) was added and the mixture was filtered to obtain the product as a pale gray solid (4.1 g). The methylene chloride layer was separated, washed with H2O, dried over Na2SO4, filtered and concentrated in vacuo to a black gum. The gum was dissolved in ethyl acetate (150 ml). This solution was extracted with 10×50 ml of 0.25N KOH. The individual extracts were acidified and solids were filtered and dried. Total product obtained was 19 g or 55% yield. Pure product melted at 182.5°-184° C.