Water → Methyl 4-(benzoxazol-2-yl)benzoate

HRID 8974

Reaction equation

HRID 8974 reaction equation
[CH3:1][O:2][C:3](=[O:20])[C:4]1[CH:12]=[CH:11][C:7]([C:8]([NH2:10])=[O:9])=[CH:6][C:5]=1C1C=CC=CC=1O.O.C([O-])([O-])=O.[K+].[K+]>C(OCC)(=O)C>[O:9]1[C:5]2[CH:6]=[CH:7][CH:11]=[CH:12][C:4]=2[N:10]=[C:8]1[C:7]1[CH:6]=[CH:5][C:4]([C:3]([O:2][CH3:1])=[O:20])=[CH:12][CH:11]=1

Participants

5

Reactant 3

HCID 962WaterHCID 11430Potassium CarbonateHCID 68619610(2-Hydroxyphenyl)-terephthalamic acid methyl ester

Product 1

HCID 650931Methyl 4-(benzoxazol-2-yl)benzoateYield 91.1%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Conditions

Temperature
0 °C

Procedure

A solution of (2-hydroxyphenyl)-terephthalamic acid methyl ester (0.35 g, 1.3 mmol) in polyphosphoric acid (˜5 mL) was heated to reflux for 3 h. The solution was cooled to 0° C., water added (100 mL) and solid K2CO3 introduced until pH 7–9 was attained. The residue was diluted with ethyl acetate (2×100 mL) and the organic extract dried (MgSO4), filtered and concentrated to give cyclized methyl 4-(benzoxazol-2-yl)-benzoate (0.15 g, 45%) as a beige powder. 1H NMR (CDCl3) δ 3.98 (s, 3H), 7.40 (m, 2H), 7.61 (m, 1H), 7.81 (m, 1H), 8.20 (d, 2H, J=7.8 Hz), 8.34 (d, 2H, J=7.8 Hz).

Workup

  1. temperatureto reflux for 3 h
  2. additionintroduced until pH 7–9
  3. extractionthe organic extract
  4. dry with materialdried (MgSO4)
  5. filtrationfiltered
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-8aadbbed1f9a4ba3955d9427ac7ecc89
Source dataset
uspto-grants-2006_08
Patent number
US07091217B2

Linked notes

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