tert-butyl N-(2-oxoethyl)carbamate → [6-(4-Methoxy-benzyl)-4,5,6,7-tetrahydro-thieno[2,3-c]pyridin-7-ylmethyl]-carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 4.11-A (5.6 g, 19.7 mmol) and t-butyl (2-oxoethyl)carbamate (12.6 g, 78.9 mmol) in butanol (118 mL) was heated to 140° C. for 16 h in a reaction vessel equiped with a Dean-Stark trap. The reaction mixture was cooled to 25° C. and diluted with ethyl acetate. The starting material 4.11-A precipitates as a white solid which was collected. The ethyl acetate filtrate was washed with saturated sodium bicarbonate (2×100 mL) and brine (100 mL), dried with Na2SO4, filtered, and concentrated to give a crude oil which was purified using flash column chromatography (100% hexane →30% EtOAc/hexane) to yield 4.11-B as an amber oil (3.4 g, 44%). 1H NMR (500 MHz, CDCl3): δ 7.26–7.25 (m, 2H), 7.18 (d, J=4.9 Hz, 1H), 6.88–6.85 (m, 2H), 6.81 (d, J=4.9 Hz, 1H), 5.05–5.00 (M, 1H), 3.81 (s, 3H), 3.80–3.78 (m, 1H), 3.72–3.64 (m, 2H), 3.57–3.53 (m, 1H), 3.20–3.15 (m, 1H), 3.15–3.08 (m, 1H), 2.90–2.78 (m, 2H), 2.48–2.45 (m, 1H), 1.42 (s, 9H); LCMS found for C21H29N2O3S (M+H)+: m/z=389.

Provenance & Evidence