Aluminum(III) Chloride → 4,5,7,8-Tetrahydro-thieno[2,3-d]azepine-6-carboxylic acid ethyl ester

Participants

Reaction Steps

AlCl3 (3.95 g, 29.7 mmol) was added to 50 mL DCM at 0° C. Borane-t-butyl amine complex (5.2 g, 59.5 mmol) was added followed by the product of step c) (2.37 g, 9.9 mmol) dissolved in DCM (50 mL). The reaction was stirred for 2 hours at room temperature after which time another 3.95 g (29.7 mmol) of AlCl3 was added. After stirring 10 minutes, the reaction was quenched carefully with 0.1 M HCl (˜50 mL). After concentration of the organic solvent, the crude reaction mixture was partitioned between 1M HCl and EtOAc (70 mL each). The aqueous layer was back extracted 1× EtOAc. The combined organic layers were dried over MgSO4 and concentrated. The subtitle product (1.45 g) was obtained after purification by silica gel chromatography (EtOAc/Hexanes-gradient). 1H NMR (300 MHz, CDCl3) 6.96 (d, J=5 Hz, 1H), 6.76 (d, J=5 Hz, 1H), 4.18 (q, J=7 Hz, 2H), 3.52-3.78 (m, 4H), 2.78-3.08 (m, 4H), 1.28 (t, J=7 Hz, 3H). MS: ESI (positive): 226 (M+H).

Provenance & Evidence