Diazomethane → L-Cysteine, N-acetyl-, methyl ester

Participants

Reaction Steps

N-Acetyl-L-cysteine (5 g, 30.6 mM) was treated with excess diazomethane (generated from N-nitrosomethyl urea) in ether for 6 hr at RT. Unreacted starting material was removed by filtration and the resulting yellow filtrate was allowed to stand overnight. The solvent was removed in vacuo and the residue crystallized from Et2O/Pet. ether to give pure N-acetyl-L-cysteine methyl ester (650 mg); mp 73°-76° C. compared to a literature mp of 81°-82° C. in the Journal of Organic Chemistry, Vol. 35, p. 3542 (1970) and 79°-80° C. in the Canadian Jounral of Chemistry, Vol. 44, p. 2517 (1966).

Provenance & Evidence