2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 5-Bromo-3-methyl-1,2-benzoxazole

HRID 2194557Notes

Reaction equation

HRID 2194557 reaction equation
C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.ClC1C(=O)C(C#N)=C(C#N)C(=O)C=1Cl.[Br:34][C:35]1[CH:36]=[CH:37][C:38]([OH:45])=[C:39](/[C:41](=[N:43]/O)/[CH3:42])[CH:40]=1>C(Cl)Cl>[Br:34][C:35]1[CH:36]=[CH:37][C:38]2[O:45][N:43]=[C:41]([CH3:42])[C:39]=2[CH:40]=1

Participants

5

Reactant 3

HCID 67752,3-Dichloro-5,6-dicyano-1,4-benzoquinoneHCID 11776TriphenylphosphineHCID 1355380141-(5-Bromo-2-hydroxyphenyl)ethanone oxime

Product 1

HCID 124113305-Bromo-3-methyl-1,2-benzoxazoleYield 65.1%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a stirred solution of triphenylphosphine (6.8 g, 26.1 mmol) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) (3.9 g, 26.1 mmol) in CH2Cl2 (50 mL) was added (E)-1-(5-bromo-2-hydroxyphenyl)ethanone oxime (11) (5.0 g, 21.73 mmol) in small portions over a period of 15 min. The mixture was stirred for additional 10 min at room temperature and then the solvent was removed under reduced pressure. The residue was purified by flash column chromatography (silica gel, eluting with 5% ethyl acetate and hexanes) to give the title compound (12) (3.0 g, 65%) as a brown solid. 1H NMR (CDCl3, 400 MHz) δ 7.79 (s, 1H), 7.40 (dd, J=8.4, 1.6 Hz, 1H), 7.35 (d, J=8.4 Hz, 1H), 2.64 (s, 3H); MS (ESI, M+H+) C8H7BrNO, calcd. 212.0. found 212.0, 214.0.

Workup

  1. customthe solvent was removed under reduced pressure
  2. customThe residue was purified by flash column chromatography (silica gel, eluting with 5% ethyl acetate and hexanes)

Sources & evidence

ORD record
ord-4e8c991aaa9f47048766b590973032ac
Source dataset
uspto-grants-2012_12
Patent number
US08334292B1

Reaction notes

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