2H-3-Benzazepin-2-one, 1,3,4,5-tetrahydro- → 2,3,4,5-Tetrahydro-1H-benzo(d)azepine

Participants

Reaction Conditions

Reaction Steps

A solution of 4,5-dihydro-1H-benzo[d]azepin-2(3H)-one (3.5 mmol) was in THF (25 mL) was stirred at 0° C. for 5 min. A solution of 1M BH3.THF (4 mL) was added dropwise to the reaction mixtureat 0° C. over a period of 30 min. The ice bath was removed and the reaction stirred at RT for 30 min. The reaction mixture was heated at 60° C. overnight, then cooled to 0° C. and additional 1M BH3.THF (2.5 mL) was added dropwise into the reaction mixtureat 0° C. over a period of 15 min. The ice bath was removed and it was stirred at RT for 30 min then heated at 60° C. for 7 h. The reaction mixture was cooled to RT, then further cooled with an ice-bath. The reaction was quenched by the addition of 2M HCl (15 mL). The mixture was heated for 30 min and then 20% NaOH (7.5 mL) was added with ice cooling. The solution was extracted with chloroform (3×) and the organic layer was washed with H2O. The organic layer was dried (Na2SO4), concentrated and redissolved in 2 mL of EtOAc and acidified with 3M HCl/EtOAc. The solid was filtered and dried under vacuum to obtain 2,3,4,5-tetrahydro-1H-benzo[d]azepine as a shiny powder (0.36 g, 69% yield). LC-MS (EI) m/z: 148.2 (M+H+).

Provenance & Evidence