Phosphorus tribromide → 1-(Bromomethyl)-3,4,5-trimethoxy-2-nitrobenzene

HRID 227358Notes

Reaction equation

HRID 227358 reaction equation
[CH3:1][O:2][C:3]1[C:4]([N+:16]([O-:18])=[O:17])=[C:5]([CH:9]=[C:10]([O:14][CH3:15])[C:11]=1[O:12][CH3:13])[CH2:6]CO.P(Br)(Br)[Br:20]>C(Cl)Cl>[N+:16]([C:4]1[C:3]([O:2][CH3:1])=[C:11]([O:12][CH3:13])[C:10]([O:14][CH3:15])=[CH:9][C:5]=1[CH2:6][Br:20])([O-:18])=[O:17]

Participants

4

Reactant 2

HCID 24614Phosphorus tribromideHCID 866198443,4,5-Trimethoxy-2-nitrobenzyl methanol

Product 1

HCID 139729961-(Bromomethyl)-3,4,5-trimethoxy-2-nitrobenzeneYield 68%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a stirred solution of the 3,4,5-Trimethoxy-2-nitrobenzoic acid (5 g, 19.40 mmol) in THF (30 ml) was added by BH3 (1.0 M in THF, 29.1 ml) under nitrogen. The mixture was stirred and refluxed for 2 hours. After cooling, the reaction mixture was extracted with water and CH2Cl2. The combined organic layers were dried over MgSO4, and then evaporated to afford 3,4,5-Trimethoxy-2-nitrobenzyl methanol. The crude 3,4,5-trimethoxy-2-nitrobenzyl methanol was dissolved in anhydrous CH2Cl2 (20 mL) and was subjected to PBr3 (2.40 ml, 25.22 mmol) in an ice bath. After 2 h, the mixture was extracted with water and CH2Cl2. The organic layers were combined and evaporated. The residue was purified by flash chromatography (EtOAc:n-hexane=1:2) to afford B1 as a pale yellow oil, yield 68%. 1H NMR (500 MHz, CDCl3) δ 3.90 (s, 3H), 3.92 (s, 3H), 3.98 (s, 3H), 4.44 (s, 2H), 6.72 (s, 1H).

Workup

  1. extractionthe mixture was extracted with water and CH2Cl2
  2. customevaporated
  3. customThe residue was purified by flash chromatography (EtOAc:n-hexane=1:2)

Sources & evidence

ORD record
ord-3f030659f4a34766bc09b820aaab3646
Source dataset
uspto-grants-2009_07
Patent number
US07560491B2

Reaction notes

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