Sodium Hydroxide → 9-(2-Benzyloxy-ethyl)-2,3,4,9-tetrahydro-1H-carbazole-4-carboxylic acid

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Reaction Steps

9-(2-Benzyloxy-ethyl)-2,3,4,9-tetrahydro-1H-carbazole-4-carboxylic acid ethyl ester (25) (35 g, 9.3 mmol) was dissolved in ethanol (9 mL) and then NaOH (1.56 g) in water (15 mL) was added. The reaction was heated at reflux for 2 h. The reaction was concentrated in vacuo and the residue diluted with water and washed with dichloromethane (2×150 mL). The aqueous layer was added drop wise to 2 N HCl (150 mL) and then extracted into dichloromethane (3×150 mL). The organics were dried and concentrated in vacuo to afford 2.48 g (92%) of 9-(2-benzyloxy-ethyl)-2,3,4,9-tetrahydro-1H-carbazole-4-carboxylic acid (26) as a yellow solid which was used in the next step without purification. The structure was confirmed by 13C NMR (75 MHz, CDCl3) δC 20.4, 21.8, 26.4, 38.3, 42.9, 68.7, 73.3, 105.7, 108.8, 118.7, 119.3, 102.9, 127.4, 127.6, 128.3, 136.2, 137.1, 137.8, 108.9.

Provenance & Evidence