Phosphorus trichloride → 2-Methyl-1,3-benzoxazol-6-ol
Reaction equation
[OH:1][C:2]1[CH:7]=[C:6]([OH:8])[CH:5]=[CH:4][C:3]=1C(=NO)C.P(Cl)(Cl)Cl.C([O-])(=O)C.[Na+].[C:22](#[N:24])[CH3:23].CC(N(C)C)=O>>[CH3:23][C:22]1[O:1][C:2]2[CH:7]=[C:6]([OH:8])[CH:5]=[CH:4][C:3]=2[N:24]=1Participants
5
Conditions
- Temperature
- 22.5 °C
Procedure
To a mixture of 1-(2,4-dihydroxy-phenyl)-ethanone oxime (4.2 g, 25 mmol) and acetonitrile/dimethylacetamide (20 mL, 3:1) cooled by a water bath (20-25° C.) was added dropwide phosphorus chloride (2.4 mL, 26.2 mmol) over a period of fifteen minutes. The mixture was stirred for an additional thirty minutes before it was poured into ice water containing sodium acetate (6 g). The mixture was stirred for ten minutes, filtered, and the filter cake was washed with water and dried in vacuo to give the title compound as a yellow solid (3.15 g): 1H NMR (CDCl3, 200 MHz): δ=7.45 (m, 1H), 6.96 (m, 1H), 6.80 (m, 1H), 2.60 (s, 3H).
Workup
- stirringThe mixture was stirred for ten minutes
- filtrationfiltered
- washthe filter cake was washed with water
- customdried in vacuo
Sources & evidence
- ORD record
- ord-7cf7ca2d4cb04730b3ec44195e576749
- Source dataset
- uspto-grants-2014_06
- Patent number
- US08759373B2
Reaction notes
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