Triethyl phosphite → [phosphono(thiomorpholin-4-yl)methyl]phosphonic acid

Participants

Reaction Steps

Oxalyl chloride (16.6 ml) was added dropwise at 0° C. to a stirred solution of N-formyl-thiomorpholine (26.2 g) in methylene chloride (200 ml). The mixture was stirred at room temperature until the gas evolution ceased (about 5 hours later). Triethyl phosphite (66 ml) was then added during 1.5 hours at room temperature. Unreacted triethyl phosphite was removed in vacuo, and the residue was refluxed with 20% hydrochloric acid (150 ml) for 3 hours. The mixture was evaporated to dryness in vacuo, and the residue was stirred with acetone. The crystalline product was filtered and recrystallized from water. M.p.: >250° C. (dec.).

Provenance & Evidence