4-Methylmorpholine → HCID 16124590, compound

Participants

Reaction Conditions

Reaction Steps

(2R)-4-[(Benzyloxy)carbonyl]-1-(tert-butoxycarbonyl)piperazine-2-carboxylic acid (1.4 g, 3.9 mmol) was dissolved in dimethoxyethane (10 mL) and to the cooled resultant solution was added N-methylmorpholine (0.4 g, 3.9 mmol) followed by isobutyl chloroformate (0.54 g, 3.9 mmol) by means of drops. The mixture was stirred at 0° C. for 20 min and then the mixture was filtered. The filtrate was transferred to a 500 mL flask and then cooled again. Sodium borohydride (0.22 g, 5.9 mmol) dissolved in water (5 mL) was added and the external cooling bath was removed. The reaction mixture was stirred until the temperature of it had reached RT whereupon water (120 mL) was added. The mixture was extracted trice with ethyl acetate and the combined organic solutions were dried and then evaporated. The product was purified by column chromatography on silica gel (ethyl acetate-heptane 10% to 70%). There was obtained 1.2 g (84%) of 4-benzyl 1-tert-butyl (2R)-2-(hydroxymethyl)piperazine-1,4-dicarboxylate as a colorless oil. 1H NMR (500 MHz, CDCl3): 1.4 (s, 9H), 2.7-3.2 (b, 4H), 3.5 (b, 2H), 3.8-4.2 (m, 4H), 5.1 (m, 2H), 7.2-7.4 (m, 5H); LCMS: m/z 349 (M−1)−.

Provenance & Evidence