4-Methylmorpholine → HCID 56639216, compound

Participants

Reaction Steps

To a vigorously stirred solution of N-[(1,1-dimethylethoxy)carbonyl]-L-alanine (15.14 g., 80 mmole) and N-methylmorpholine (8.80 ml., 80 mmole) in dry tetrahydrofuran (80 ml.) at -15° under argon is added a solution of isobutyl chloroformate (10.37 ml., 80 mmole) in tetrahydrofuran (10 ml.) while maintaining the reaction temperature below -12°. After the addition is complete, the reaction mixture is stirred for 14 minutes, diluted with anhydrous ether (250 ml., prechilled to -20°), and quickly filtered. Approximately one-fourth of the filtrate is transferred to a separatory funnel (the remainder is kept chilled) and added rapidly to a gently stirred, chilled (0°) solution of diazomethane (160 mmole). Additional chilled portions are transferred to the separatory funnel until the entire solution has been added (approximately 10 minutes). The resulting solution is stirred for 2 hours, warming gently to room temperature, then purged with nitrogen for 1 hour, washed with chilled half-saturated sodium bicarbonate (2×100 ml.) and water (3×50 ml.), dried (Na2SO4), and evaporated to a yellow semi-crystalline residue. Two recrystallizations from ethyl acetate-petroleum ether yield 10.29 g. of product as yellow plates; m.p. 99°-102° plus an additional crop of 1.33 g.; m.p. 97.5°-101°. A portion is recrystallized once more giving an analytically pure sample of (S)-(3-diazo-1-methyl-2-oxopropyl)carbamic acid, 1,1-dimethylethyl ester; m.p. 102°-103°.

Provenance & Evidence