Boron tribromide → [1R*,8S*,9aR*]1-Amino-5,6-dihydroxy-8-phenyl-2,3,7,8,9,9a-hexahydrophenalene hydrobromide

HRID 233411Notes

Reaction equation

HRID 233411 reaction equation
[NH2:1][C@H:2]1[C@H:13]2[C:14]3[C:5](=[CH:6][C:7]([O:23]C)=[C:8]([O:21]C)[C:9]=3[CH2:10][C@@H:11]([C:15]3[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=3)[CH2:12]2)[CH2:4][CH2:3]1.B(Br)(Br)[Br:26]>C(Cl)Cl>[BrH:26].[NH2:1][C@H:2]1[C@H:13]2[C:14]3[C:5](=[CH:6][C:7]([OH:23])=[C:8]([OH:21])[C:9]=3[CH2:10][C@@H:11]([C:15]3[CH:16]=[CH:17][CH:18]=[CH:19][CH:20]=3)[CH2:12]2)[CH2:4][CH2:3]1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 18641659HCID 18641659, compound

Product 1

HCID 18641657[1R*,8S*,9aR*]1-Amino-5,6-dihydroxy-8-phenyl-2,3,7,8,9,9a-hexahydrophenalene hydrobromideYield 69%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a solution of 0.4 g (1.2 mmol) of [1R*,8S*,9aR*]1-amino-5,6-dimethoxy-8-phenyl-2,3,7,8,9,9a-hexahydrophenalene in 9 mL of methylene chloride at -78° C., was added dropwise 4.4 mL (4.4 mmol) of a 1M solution of boron tribromide in methylene chloride. The reaction mixture was warmed to ambient temperature for 1 hour and cooled to -78° C. and the reaction was quenched by the addition of 5 mL of methanol. The reaction was allowed to warm to ambient temperature and stirred for 1 hour. The solvent was removed in vacuo. Methanol (5 mL) was added and the solution was concentrated to remove methyl borate by azeotropic distillation. The title compound was obtained (0.32 g, 69% yield) after recrystallization from ethanol/diethyl ether as a white solid; DCI MS: 279 (M+H)+, 296 (M-NH4)+. 1H NMR (d6 -DMSO) δ:1.4-1.6 (m, 1H), 1.7-1.9 (m, 1H), 2.1-2.2 (m, 1H), 2.2-2.3 (m, 1H), 2.4-2.5 (m, 2H), 2.7-3.2 (m, 5H), 6.41 (s, 1H), 7.2-7.4 (m, 5H), 8.0 (br s, 5H). Analysis calculated for C19H22BrNO2 +0.5 H2O: C, 59.23; H, 5.99; N, 3.64. Found: C, 59.26; H, 5.86; N, 3.59.

Workup

  1. temperaturecooled to -78° C.
  2. customthe reaction was quenched by the addition of 5 mL of methanol
  3. temperatureto warm to ambient temperature
  4. customThe solvent was removed in vacuo
  5. additionMethanol (5 mL) was added
  6. concentrationthe solution was concentrated
  7. customto remove methyl borate
  8. distillationby azeotropic distillation

Sources & evidence

ORD record
ord-5401b638720547c38cf6c34f67082b0b
Source dataset
uspto-grants-1997_01
Patent number
US05591884

Reaction notes

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