Methanol → HCID 68698202, compound

Participants

Reaction Steps

A 3 N aqueous KOH solution (6.5 mL, 19.5 mmol, 3 equiv.) was added to a solution of 4-methoxy-2,3-dihydro-indole-1,6-dicarboxylic acid 1-tert-butyl ester 6-methyl ester (2 g, 6.5 mmol, 1 equiv.) in a 1:4 MeOH:tetrahydrofuran solution (20 mL) and the mixture was shaken for 16 hours. The methanol was removed under vacuum and the pH was adjusted to 3 with 3 N aqueous HCl solution. The resulting slurry was diluted with ethyl acetate (20 mL), the organic layer was separated and the aqueous phase was extracted with EtOAc (2×20 mL). The organic layers were combined, dried over Na2SO4 and the solvent was removed under vacuum to afford 4-methoxy-2,3-dihydro-indole-1,6-dicarboxylic acid 1-tert-butyl ester, 1.68 g (88% yield). LC @215 nm; Rt 1.44: 83%, m/z (ES+): 238 (M-Boc+MeCN+H+.); δH (400 MHz; d6-DMSO) 12.58 (1H, br.s) 7.97 (1H, br.s), 6.94 (1H, d), 3.70 (2H, t), 3.61 (3H, s), 2.75 (2H, t), 1.28 (9H, s).

Provenance & Evidence