Triphenylphosphine → 2-Bromo-5-bromomethylpyridine

HRID 1496898Notes

Reaction equation

HRID 1496898 reaction equation
[Br:1][C:2]1[N:7]=[CH:6][C:5]([CH2:8]O)=[CH:4][CH:3]=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[Br:29]N1C(=O)CCC1=O>C(Cl)Cl>[Br:1][C:2]1[CH:3]=[CH:4][C:5]([CH2:8][Br:29])=[CH:6][N:7]=1

Participants

5

Reactant 3

HCID 11776TriphenylphosphineHCID 67184N-bromobutanimideHCID 64212496-Bromo-3-pyridinemethanol

Product 1

HCID 64246602-Bromo-5-bromomethylpyridineYield 91.2%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A solution of (6-bromo-3-pyridinyl)methanol (50) (2.503 g, 13.3 mmol) and triphenylphosphine (4.026 g, 15.4 mmol) in anhydrous CH2Cl2 (100 mL) was carefully treated with recrystallized N-bromosuccinimide (2.732 g, 15.4 mmol) (water bath cooling), and the mixture was stirred at room temperature for 3.5 h. The resulting solution was concentrated, and then added to excess petroleum ether at the top of a silica gel column (100 g in petroleum ether), rinsing on with minimal extra CH2Cl2. Elution with petroleum ether firstly gave foreruns, and then further elution with 15-25% Et2O/pentane gave pure 2-bromo-5-(bromomethyl)pyridine (51) (Schubert et al., 1999) (3.045 g, 91%) as a lachrymatory white solid that was used directly in the next step; 1H NMR (CDCl3) δ 8.38 (d, J=2.5 Hz, 1H), 7.59 (dd, J=8.2, 2.6 Hz, 1H), 7.48 (d, J=8.2 Hz, 1H), 4.42 (s, 2H).

Workup

  1. concentrationThe resulting solution was concentrated
  2. additionadded to excess petroleum ether at the top of a silica gel column (100 g in petroleum ether)
  3. washrinsing on with minimal extra CH2Cl2
  4. washElution with petroleum ether firstly gave foreruns
  5. washfurther elution with 15-25% Et2O/pentane

Sources & evidence

ORD record
ord-79062b26598d43759fdf78455e3e2d95
Source dataset
uspto-grants-2015_12
Patent number
US09198913B2

Reaction notes

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