Boron tribromide → Cis-2-(3,4-dihydroxybenzyl)-5-[2-(4-hydroxyphenyl)ethyl]pyrrolidine hydrobromide

HRID 256196Notes

Reaction equation

HRID 256196 reaction equation
Cl.C[O:3][C:4]1[CH:5]=[C:6]([CH:23]=[CH:24][C:25]=1[O:26]C)[CH2:7][C@H:8]1[CH2:12][CH2:11][C@@H:10]([CH2:13][CH2:14][C:15]2[CH:20]=[CH:19][C:18]([O:21]C)=[CH:17][CH:16]=2)[NH:9]1.B(Br)(Br)[Br:29]>C(Cl)Cl>[BrH:29].[OH:3][C:4]1[CH:5]=[C:6]([CH:23]=[CH:24][C:25]=1[OH:26])[CH2:7][C@H:8]1[CH2:12][CH2:11][C@@H:10]([CH2:13][CH2:14][C:15]2[CH:20]=[CH:19][C:18]([OH:21])=[CH:17][CH:16]=2)[NH:9]1

Participants

4

Reactant 2

HCID 25134Boron tribromide2×HCID 13065028cis-2-(3,4-Dimethoxybenzyl)-5-[2-(4-methoxyphenyl)ethyl]pyrrolidine hydrochloride

Product 1

HCID 13065031Cis-2-(3,4-dihydroxybenzyl)-5-[2-(4-hydroxyphenyl)ethyl]pyrrolidine hydrobromide

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a cold solution of 3 g. (0.008 mole) of cis-2-(3,4-dimethoxybenzyl)-5-[2-(4-methoxyphenyl)ethyl]pyrrolidine hydrochloride in 50 ml. of methylene chloride was added dropwise 8 g. (0.032 mole) of boron tribromide at -60° C. After addition of boron tribromide was finished, the cold bath was removed, and the reaction mixture was gradually warmed up to room temperature over a period of about one and a half hours. The mixture was then cooled again in a Dry Ice-acetone bath and 25 ml. of methanol was carefully added. After methanol was completely removed, the residue was treated with ethyl acetate. Upon storing in a freezer, an off-white solid crystallized out, which was recrystallized from ethyl acetate and ethanol to give 3.11 g. of pure product, m.p. 195°-198° C.

Workup

  1. customat -60° C
  2. customthe cold bath was removed
  3. temperatureThe mixture was then cooled again in a Dry Ice-acetone bath
  4. additionof methanol was carefully added
  5. customAfter methanol was completely removed
  6. additionthe residue was treated with ethyl acetate
  7. customan off-white solid crystallized out
  8. customwhich was recrystallized from ethyl acetate and ethanol
  9. customto give 3.11 g

Sources & evidence

ORD record
ord-af9802e1b9804afdac08859cb1d2c463
Source dataset
uspto-grants-1987_10
Patent number
US04701461

Reaction notes

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