(-)-Mandelic acid → HCID 131727233, compound

Participants

Reaction Conditions

Reaction Steps

1-Amino-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepin-2-one (31.9 g, 168 mmol) was slurried in about 300 mL isopropyl acetate and heated to 45° C. In a separate flask, (R)-(−)-D-mandelic acid (25.0 g, 164 mmol) was heated in about 130 mL of isopropyl alcohol until a solution formed and was added to the 1-amino-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepin-2-one/isopropyl acetate slurry obtained above to give a solution from which a precipitate quickly formed. The mixture was stirred at 45° C. for about 3 hours. 5-Nitrosalicylaldehyde (2-hydroxy-5-nitrobenzaldehyde) (1.40 g, 8.38 mmol, 5 mol %) was added to the warm solution and the mixture was stirred at 45° C. After about 14 hours, the slurry was cooled to ambient temperature and stirred for 2 hours before the solids were collected by filtration and rinsed with 70 mL of cold isopropyl acetate, and dried in the vacuum oven at 40° C. to obtain 46.62 g of (S)-1-amino-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepin-2-one (R)-mandelic acid salt (82.9% yield, 98.4% ee).

Provenance & Evidence