Sodium hydride → 2,2-Dimethyl-propionic acid 2-(2,8-dimethyl-1,2,3,4-tetrahydro-pyrido[4,3-b]indol-5-yl)-1-methyl-1-pyridin-3-yl-ethyl ester

Participants

Reaction Steps

1-(2,8-Dimethyl-1,2,3,4-tetrahydro-pyrido[4,3-b]indol-5-yl)-2-pyridin-3-yl-propan-2-ol (5.0 g, 14.9 mmol) was dissolved in DMF (100 mL) and sodium hydride (1.8 g, 45 mmol) was added, and the mixture stirred at RT for 15 min. Pivaloyl chloride (3 g, 25 mmol) was added dropwise at the same temperature, and the mixture stirred for 45 min. The reaction was monitored by TLC and LCMS. The reaction mixture was poured into 400 mL ice water to obtain a solid that was filtered. The solid was dissolved in DCM, dried over sodium sulfate and concentrated to obtain the crude product that was purified by column chromatography (silica gel: 100-200 mesh, Eluent: −4-6% MeOH in DCM) to obtain 1.8 g of 2,2-dimethyl-propionic acid 2-(2,8-dimethyl-1,2,3,4-tetrahydro-pyrido[4,3-b]indol-5-yl)-1-methyl-1-pyridin-3-yl-ethyl ester. The product was further purified by chiral preparative HPLC to give enantiomers II-16a and II-16b. 1H NMR (CDCl3, Free base): δ (ppm): 8.55 (d, 1H), 8.5 (s, 1H), 7.2 (d, 1H), 7.18 (m, 3H), 6.9 (d, 1H), 4.3 (dd, 2H), 3.65 (d, 1H), 3.52 (d, 1H), 2.65 (m, 2H), 2.5 (m, 2H), 2.5 (s, 3H), 2.4 (s, 3H), 2.3 (d, 1H), 2.0 (s, 3H), 2.0 (m, 1H), 1.2 (s, 9H).

Provenance & Evidence