4-Benzyl-6,6-dimethyl-morpholine-3-carboxylic acid benzyl ester → 6,6-Dimethylmorpholine-3-carboxylic acid

Participants

Reaction Steps

To a solution of 4-benzyl-6,6-dimethyl-morpholine-3-carboxylic acid benzyl ester (Intermediate 18, 1.25 g) in 40 ml of 10% AcOH/MeOH (under nitrogen) was added 250 mg of 20% Pd(OH)2 on charcoal. The reaction mixture was purged with hydrogen (balloon) and was stirred at ambient temperature for 72 hrs. To the resulting gray mixture was added 4 ml of water to help dissolution. The catalyst was removed by filtration and the filtrate was concentrated to dryness. The residue was co-evaporated with ethanol (2×) and then triturated with EtOAc. The generated white solid was filtered off and dried under high vacuum to give 559 mg of 6,6-dimethyl-morpholine-3-carboxylic acid (95% yield). 1H-NMR (300 MHz, D2O): δ 1.35 (s, 3H), 1.38(s, 3H), 3.11 (d, 1H), 3.32 (d, 1H), 3.81-3.87 (m, 1H), 4.05 (bt, 1H), 4.17 (bd, 1H). MS (M+H+): 160.

Provenance & Evidence