p-Toluenesulfonic acid → 2-Phenyl-1,3-benzoxazole-6-carboxylic acid

HRID 1481690Notes

Reaction equation

HRID 1481690 reaction equation
[C:1]([NH:9][C:10]1[CH:18]=[CH:17][C:13]([C:14]([OH:16])=[O:15])=[CH:12][C:11]=1[OH:19])(=O)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.CC1C=CC(S(O)(=O)=O)=CC=1>>[C:2]1([C:1]2[O:19][C:11]3[CH:12]=[C:13]([C:14]([OH:16])=[O:15])[CH:17]=[CH:18][C:10]=3[N:9]=2)[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

3

Reactant 2

HCID 6101p-Toluenesulfonic acidHCID 608270074-Benzamido-3-hydroxybenzoic acid

Product 1

HCID 109007142-Phenyl-1,3-benzoxazole-6-carboxylic acidYield 99.5%

Conditions

Temperature
160 °C

Procedure

To a suspension of 4-benzamido-3-hydroxybenzoic acid (2.15 g, 8.4 mmol) in xylenes (12 mL) was added p-TsOH (1.6 g, 8.4 mmol, 1.0 eq) at room temperature then the mixture was heated to 160° C. and stirred overnight. The solvent was removed under reduced pressure then the reaction was quenched with saturated aqueous NaHCO3 and biphasic mixture was extracted by CH2Cl2 (4×80 mL). The solvent was concentrated to give the title compound (2.0 g) which was used in the next step without further purification. LC-MS 237.9 [M−H]−, 240.3 [M+H]+, RT 1.12 min.

Workup

  1. customThe solvent was removed under reduced pressure
  2. customthe reaction was quenched with saturated aqueous NaHCO3 and biphasic mixture
  3. extractionwas extracted by CH2Cl2 (4×80 mL)
  4. concentrationThe solvent was concentrated

Sources & evidence

ORD record
ord-24c4bb4fb44c4b16ab1feaddadcc64dc
Source dataset
uspto-grants-2016_08
Patent number
US09409905B2

Reaction notes

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