Methanol → Methyl 5-oxo-L-prolinate

Participants

Reaction Conditions

Reaction Steps

A 500 g sample of L-pyroglutamic acid was added to 2.8 L of anhydrous methanol, 28 mL of H2SO4 was added, and the mixture was stirred for 4 hr at 60° C. The reaction mixture was cooled to room temperature, 262 g of NaHCO3 was added, and the mixture was stirred for an additional 16 hr. The mixture was dried by addition of 314 g of Na2SO4 with stirring for 1 hr, then the mixture was filtered and the solvent was evaporated under vacuum to yield a pale yellow oil. The oil was dissolved in THF, and a small amount of unreacted acid was filtered off. The THF was removed under vacuum, and the residual oil was dried by azeotropic distillation with toluene.

Provenance & Evidence