Acetyl chloride → 2-Acetyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid

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Reaction Steps

To a mixture of acetone (75 mL) and 2N NaOH (100 mL) was added portionwise 1,2,3,4-tetrahydro-isoquinoline-3-carboxylic acid hydrochloride (10.00 g, 46.8 mmol). After stirring for 10 min, acetyl chloride (7.38 g, 94 mmol) in acetone (50 mL) was added slowly into the above solution, followed with 2N NaOH at room temperature. The reaction mixture was maintained at a pH>10 and stirred for 1 hour. The acetone was evaporated in vacuo and acidified the residue by adding 3N HCl. The separated solid was collected by filtration, washed several times with water, and dried to afford the known 2-acetyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid as an enantiomeric mixture, 7.90 g, (76.9%); mp 178-180° C. (170-171° C.):21 1H NMR (DMSO-d6) δ 2.15 (3H, s, Me), 3.02-3.24 (2H, m), 4.29-4.75 (2H, m), 4.98-5.17 (1H, m), 7.17-7.21 (4H, m, 4×ArH), 12.70 (1H, brs, exchangeable, OH); m/z219.0 (M+H)+.

Provenance & Evidence