Phosphorus sulfide (P2S5) → (2-Methoxy-5-morpholin-4-yl-phenylamino)-thioxo-acetic acid

Participants

Reaction Steps

To 33.9 g (110 mmol) N-(2-methoxy-5-morpholin-4-yl-phenyl)-oxalamic acid ethyl ester in 652 ml boiling xylene was added 8.80 g (40 mmol) phosphorus pentasulfide in small portions over a period of 30 minutes. The mixture was refluxed for 5 hours, cooled to room temperature and filtered. The solution was extracted 7 times with 100 ml 1N NaOH. The aqueous phase was washed twice with 100 ml toluene, filtered, and treated at 0–5° C. with concentrated hydrochloric acid until pH 1 was reached. Filtration of the precipitate yielded 20.2 g (62%) (2-methoxy-5-morpholin-4-yl-phenylamino)-thioxo-acetic acid as yellow crystals with M.p.: 156–158° C., MS m/e (%): 297 (M+H+, 100).

Provenance & Evidence