4-Aminobenzoic Acid → Benzenamine, 4-(2-benzoxazolyl)-

HRID 363304

Reaction equation

HRID 363304 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[OH:8].[NH2:9][C:10]1[CH:18]=[CH:17][C:13]([C:14](O)=O)=[CH:12][CH:11]=1>C(=O)(O)[O-].[Na+]>[NH2:9][C:10]1[CH:18]=[CH:17][C:13]([C:14]2[O:8][C:3]3[CH:4]=[CH:5][CH:6]=[CH:7][C:2]=3[N:1]=2)=[CH:12][CH:11]=1

Participants

4

Reactant 2

HCID 9784-Aminobenzoic AcidHCID 58012-Aminophenol

Product 1

HCID 88733Benzenamine, 4-(2-benzoxazolyl)-Yield 62%

Reagents, catalysts & solvents 1

HCID 516892Sodium BicarbonateSolvent

Conditions

Temperature
190 °C

Procedure

This provides an example of a benzoxazole instead of a benzothiazole. In accordance with synthetic Route A, a mixture of 2-aminophenol (1.5 g, 0.0136 mol) and 4-aminobenzoic acid (1.885 g, 0.0136 mol) in polyphosphoric acid (20 g) was heated at about 190° C. for 4 hours, then cooled and poured into 10% aqueous sodium bicarbonate (400 ml). The product was collected by filtration, washed with water and recrystallised from methanol-H2O (10:1) to give small pale yellow crystals (1.76 g, 62%), m.p. 176°-178° C. (lit 185° C.); vmax /cm-1 3472, 3322, 3186, 1614, 1500, 1454, 1312, 1242, 1170, 1066, 830, 742; δH (DMSO-d6) 7.87(2H, d, J8.6, 2',6'-H), 7.69-7.64(2H, m, 5, 6-H), 7.36-7.28(2H, m, 4, 7-H), 6.70(2H, d, J8.6, 3', 5'-H), 6.02 (2H, s, NH2).

Workup

  1. temperaturecooled
  2. filtrationThe product was collected by filtration
  3. washwashed with water
  4. customrecrystallised from methanol-H2O (10:1)

Sources & evidence

ORD record
ord-890d30d356be4c3eb60b3ec5ddfa4987
Source dataset
uspto-grants-1999_02
Patent number
US05874431

Linked notes

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