Hydrochloric Acid → 6-amino-2,3-dihydro-1H-indene-5-carboxylic acid

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Reaction Steps

Add 30% aqueous hydrogen peroxide solution (3 mL) to a solution of 1,5,6,7-Tetrahydro-1-aza-s-indacene-2,3-dione (2.18 g, 11.66 mmol) in 2 N sodium hydroxide (23 mL) over a period of 5 minutes, stir the mixture at room temperature for 3 h. Add 1N hydrochloric acid to pH=5 and extract with ethyl acetate (3×20 mL). Wash with brine, dry the organic layer over anhydrous sodium sulfate, filter and remove the solvent under reduced pressure to afford 6-Amino-indan-5-carboxylic acid (1.7 g, 86%). Dissolve in ethylacetate (2 mL) and ethanol (2 mL) and add (trimethylsilyl) diazomethane (9.6 mL, 19.2 mmol, 2M in hexane) at room temperature and stir the solution for 16 h. Remove the solvent under reduced pressure. Chromatograph the residue over silica gel, eluting with hexanes/ethyl acetate (9:1), to afford the title compound (1.19 g, 66%). 1H NMR (CDCl3, 300 MHz) δ 2.05 (quintuplet, J=7.3 Hz, 2H), 2.80 (q, J=7.7 Hz, 4H), 6.59 (s, 1H), 7.69 (s, 1H). MS (ES+): 192 (M+H).

Provenance & Evidence