Methyl chloroglyoxylate → N-[(1-cyclohexylmethyl-7-methoxy-1H-indol-3-yl)-2-oxo-ethyl]oxalamic acid methyl ester

Participants

Reaction Steps

To a solution of (1-cyclohexylmethyl-7-methoxy-1H-indol-3-yl)-oxoacetonitrile (975 mg, 3.29 mmol) in acetic acid (40 ml) under nitrogen was added 10% palladium on charcoal (90 mg). The reaction was placed under a hydrogen atmosphere and stirred for 14 h. The reaction mixture was then filtered through a pad of dicalite. The dicalite was washed with acetic acid and the combined filtrate evaporated to leave a red oil. The red oil was taken up in dichloromethane (50 ml) and to this was added methylchlorooxoacetate (0.393 ml, 4.28 mmol) followed by N-ethyldiisopropylamine (1.7 ml, 9.87 mmol) dropwise. The reaction was stirred for 1 h and poured into a separating funnel. The organics were washed sequentially with 2M aqueous hydrochloric acid (50 ml), 5% aqueous sodium carbonate (50 ml) and brine (50 ml). The organics were dried over sodium sulfate, filtered and the solvent removed in vacuo to leave a brown oil. The oil was purified by flash chromatography using dichloromethane followed by 66% (v/v) diethyl ether in heptane to afford N-[(1-cyclohexylmethyl-7-methoxy-1H-indol-3-yl)-2-oxo-ethyl]oxalamic acid methyl ester (573 mg, 1.48 mmol) as a yellow/brown solid.

Provenance & Evidence