Sodium Hydroxide → 1-[(TERT-BUTOXY)CARBONYL]-2,3-DIHYDRO-1H-INDOLE-5-CARBOXYLIC ACID

Participants

Reaction Steps

A solution of 2,3-dihydro-indole-1,5-dicarboxylic acid 1-tert-butyl ester 5-methyl ester (2.3 g, 8.29 mmol) in methanol (30 mL) was treated with 3 N aqueous sodium hydroxide (2.77 mL, 8.29 mmol) and heated at reflux for 4 hours. An additional portion of 3N aqueous sodium hydroxide (1.38 mL, 4.14 mmol) was added and the solution was heated at reflux for an additional 28 hours. The solution was concentrated in vacuo and then diluted with water. The resultant solution was neutralized with 2N hydrochloric acid (6.3 mL). The product precipitated and was collected by filtration and washed with water, to give the product 1.5 g (69%). 1H NMR (DMSO-d6): δ 1.51 (s, 9 H), 3.10 (t, 2 H), 3.95 (t, 2 H), 7.53-7.82 (m, 3 H) and 12.59 (s, 1 H).

Provenance & Evidence