2-(3-Methoxy-allylidene)-malonic acid dimethyl ester → (S)-3-[2-tert-Butoxycarbonyl-2-(3-methoxycarbonyl-2-oxo-2H-pyridin-1-yl)-ethyl]-indole-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a solution of (S)-3-(2-Amino-2-tert-butoxycarbonyl-ethyl)-indole-1-carboxylic acid tert-butyl ester (2.5 g, 7 mmol) in methanol (15 ml) was added 2-(3-methoxy-allylidene)-malonic acid dimethyl ester (1.5 g, 7 mmol) and stirred overnight at room temperature. Sodium methoxide (78 mg, 1.4 mmol) was added and stirred for three hours at room temperature. The reaction mixture was diluted with water (50 ml) and extracted with ethylacetate (60 ml). The organic layer was washed with brine, dried (MgSO4), filtered and evaporated to afford the crude product, which was perified by flash chromatography (30-70% ethylacetate/petroleum ether) to afford the title compound as a white solid (2.3 g, 57%); 1H NMR (400 MHz, CDCl3) δ 1.43 (9H, s), 1.72 (9H, s), 3.50 (2H, m), 3.91 (3H, m), 5.68 (1H, br s), 6.08 (1H, t), 7.2-7.5 (5H, m), 8.15 (2H, m); M+H 497.5, M−H 495.5.

Provenance & Evidence