Boron tribromide → HCID 20042555, compound

Reaction equation

C[O:2][C:3]1[C:11]2[NH:10][C:9](=[O:12])[NH:8][C:7]=2[C:6]([CH:13]2[CH2:18][CH2:17][CH2:16][N:15]([CH2:19][CH2:20][CH3:21])[CH2:14]2)=[CH:5][CH:4]=1.B(Br)(Br)[Br:23]>C(Cl)Cl.CO>[BrH:23].[OH:2][C:3]1[C:11]2[NH:10][C:9](=[O:12])[NH:8][C:7]=2[C:6]([CH:13]2[CH2:18][CH2:17][CH2:16][N:15]([CH2:19][CH2:20][CH3:21])[CH2:14]2)=[CH:5][CH:4]=1

Participants

Procedure

1 g of the product of Step C in 100 ml of methylene chloride was cooled to 0°/+5° C. and over 5 minutes, 24 ml of an M solution of boron tribromide in methylene chloride were added dropwise. After stirring for 4 hours at ambient temperature and then cooling to 0° C., 50 ml of methanol were added slowly and the solvents were eliminated under reduced pressure. The residue was taken up in methanol and filtered to obtain 1.05 g of the expected product. 0.75 g of this product were purified by chromatography on silica (eluent: methylene chloride-methanol-triethylamine 8-1-1) to obtain 0.36 g of pure product which was crystallized from methanol.