Sodium hydride → Ethyl 9-(2,5-dichlorobenzyl)-9H-beta-carboline-3-carboxylate

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Reaction Steps

A suspension of ethyl 9H-β-carboline-3-carboxylate (2.40 g, 10 mmol) in anhydrous DMF (20 mL) was cooled in an ice bath under nitrogen. Sodium hydride (420 mg of 60% NaH in mineral oil, 10.5 mmol) was added at once, and the mixture stirred until most of the solids dissolved and hydrogen evolution stopped (approx 10 min). The cool mixture was treated with 2,5-dichlorobenzyl chloride (2.15 g, 1.0 mmol) slowly with stirring, then allowed to warm to room temperature over two hours. The resulting cloudy solution was neutralized with acetic acid, then the solvent was removed in vacuo, affording a tan solid (3.94 g). The crude material was chromatographed on silica gel using a mixture of chloroform and ethyl acetate, affording the title product (1.96 g, 49%). 1H NMR (300 MHz, DMSO-d6) δ9.06 (s, 1 H), 8.96 (s, 1H), 8.48 (d, J=8.0, 1H), 7.55-7.64 (m, 3H), 7.35-7.42 (m, 2H), 6.60 (d,J=2.3, 1H), 5.89 (s, 2H), 4.36 (q, J=6.9, 1H), 1.35 (t, J=7.2, 3H); LRMS calcd for C21H16Cl2N2O2 (M+H) 399, found 399.0.

Provenance & Evidence