Reaction #3665

Reaction equation

water

6,7-dihydro-5H-pyrrolo[1,2-a][1,5]benzodiazepin-6-one

diborane dimethylsulfide

NaOH

→

colorless oil

Yield 99.9%

6,7-Dihydro-5H-pyrrolo[1,2-a][1,5]benzodiazepine

Yield 99.9%

Solvents

tetrahydrofuran

tetrahydrofuran

Conditions

Workup

1. 1
   TemperatureThe mixture is refluxed for 3 hours
2. 2
   OtherThe tetrahydrofuran is removed under vacuum
3. 3
   Extractionthe residual aqueous mixture extracted with diethyl ether
4. 4
   WashThe extract is washed with brine
5. 5
   Dryingdried (Na2SO4)
6. 6
   Otherthe solvent removed

Procedure

To a solution of 0.070 g of 6,7-dihydro-5H-pyrrolo[1,2-a][1,5]benzodiazepin-6-one in 2 ml of tetrahydrofuran is added 0.45 ml of a 2.0M solution of diborane-dimethylsulfide in tetrahydrofuran. The mixture is refluxed for 3 hours, poured into water and make basic with 2N NaOH. The tetrahydrofuran is removed under vacuum and the residual aqueous mixture extracted with diethyl ether. The extract is washed with brine, dried (Na2SO4) and the solvent removed to give 0.065 g of a colorless oil; one spot by thin layer chromatography (silica gel) with ethyl acetate-hexane (1:2) as solvent (Rf 0.81).

Source