Cesium carbonate → 2-bromo-4-fluoro-6-(1-oxo-3,4,6,7,8,9-hexahydropyrazino[1,2-a]indol-2(1H)-yl)benzyl acetate

Participants

Reaction Conditions

Reaction Steps

A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer was charged with ethyl 1-(2-aminoethyl)-4,5,6,7-tetrahydro-1H-indole-2-carboxylate 101k (3.8 g, 20 mmol), 197c (20 g, 60 mmol), Xantphos (1.2 g, 2 mmol), tris(dibenzylideneacetone)dipalladium(0) (1.8 g, 2 mmol), Cs2CO3 (16 g, 50 mmol), and 1,4-dioxane (120 mL). The system was evacuated and then refilled with N2. A reflux condenser was attached to the flask, and the reaction mixture was heated at 100° C. for 16 h. It was then cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure, and the resulting residue was purified by flash column chromatography eluting with 5:1 petroleum ether/ethyl acetate to afford 197d in 60% yield (5.2 g) as a white solid. MS: [M+H]+ 435. 1H NMR (500 MHz, DMSO) δ 7.70 (dd, J=3, 1H), 7.48 (dd, J=3, 1H), 6.52 (s, 1H), 5.01 (m, 2H), 4.18 (m, 2H), 4.02 (m, 1H), 3.73 (m, 1H), 2.60 (m, 2H), 2.45 (m, 2H), 1.98 (s, 3H), 1.77 (m, 2H), 1.68 (m, 2H)

Provenance & Evidence