Hydrochloric Acid → (3aR*,10aS*)-9-Benzyl-4-(2-phthalimidoethyl)-2,3,3a,4,9,10a-hexahydrobenzo[b]cyclopenta[e][1,4]-diazepin-10(1H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of phthalimidoacetaldehyde diethyl acetal (790 mg, 3.0 mmol) in acetic acid (2.5 mL) was added conc.HCl (0.1 mL). The mixture was stirred for 80 minutes at 50° C. The reaction mixture was cooled to room temperature, to which was added (3aR*,10aS*)-9-benzyl-2,3,3a,4,9,10a-hexahydrobenzo[b]cyclopenta [e][1,4]diazepin-10(1H)-one (877 mg, 3.0 mmol), and the mixture was stirred for 25 minutes at room temperatures. To this solution was added, sodium triacetoxyborohydride (805 mg, 3.9 mmol) portionwise, and the mixture was stirred for 40 minutes at 45° C. The reaction mixture was cooled to room temperatures, to which were added dichloromethane (10 mL) and water (10 mL). The aqueous layer was separated, and the organic layer was washed with water and a saturated aqueous solution of sodium hydrogencarbonate, dried over magnesium sulfate and subjected to filtration. The filtrate was concentrated under reduced pressure. The concentrate was purified by silica-gel column chromatography (chloroform-methanol 20:1), followed by crystallization from ethanol-hexane to give 0.80 g (yield 57%) the titled compound. The sample for analytical experiment was prepared by recrystallization from dichloromethane-ethanol-hexane. m.p. 142.0°-142.6° C.

Provenance & Evidence