Trimethylaluminum → 5-(2-ethylamino-ethyl)-3-methyl-5,6,7,8-tetrahydro-1H-pyrrolo[3,2-c]azepin-4-one

Participants

Reaction Conditions

Reaction Steps

2-[3-(2-Ethylamino-ethylamino)-propyl]-4-methyl-1H-pyrrole-3-carboxylic acid ethyl ester 62c (350 mg, 1.245 mmol) and trimethyl aluminum (1.25 ml, 2.49 mmol) were dissolved in 75 ml of toluene under stirring, the resulting mixture was heated to reflux at 140° C. in an oil bath for 24 hours. After thin lay chromatography showed the disappearance of starting materials, the reaction mixture was concentrated under reduced pressure, adjusted to about pH 3 with hydrochloric acid (6 mol/L) and stirred for 30 minutes. The mixture was adjusted to pH 14 with aqueous sodium hydroxide solution (12 mol/L) and extracted with dichloromethane (100 ml×4). The combined organic extracts were washed with saturated brine (150 ml), dried over anhydrous magnesium sulfate, filtered to remove the drying agent and concentrated under reduced pressure to obtain the title compound 5-(2-ethylamino-ethyl)-3-methyl-5,6,7,8-tetrahydro-1H-pyrrolo[3,2-c]azepin-4-one 62d (450 mg) as a yellow oil to be used directly in the next step.

Provenance & Evidence