Formic Acid → HCID 86593182, compound

HRID 890608Notes

Reaction equation

HRID 890608 reaction equation
[NH2:1][C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][C:3]=1[OH:11].[CH:12](O)=[O:13]>>[C:12](=[N:1][C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][C:3]=1[OH:11])=[O:13]

Participants

3

Reactant 2

HCID 284Formic AcidHCID 1375664-Amino-3-hydroxybenzoic acid

Product 1

HCID 86593182HCID 86593182, compound

Procedure

A solution of 4-amino-3-hydroxybenzoic acid (10.0 g) in 85% formic acid (60 mL) was heated at reflux for 3 h and then cooled to room temperature. The precipitated solid was filtered, washed with methanol, and dried under vacuum to produce 4-carbonylamino-3-hydroxybenzoic acid. A portion of this material (1.00 g) and zinc chloride (3.76 g) were suspended in m-xylene (135 L), and treated with 2 drops of concentrated sulfuric acid. The reaction mixture was azeotroped for 8 h, cooled to room temperature, and treated with water (20 mL). The resulting solid was collected by filtration, washed with water, and dried under high vacuum to afford benzoxazole-6-carboxylic acid. A portion of this material (0.80 g) was suspended in anhydrous dichloromethane (30 mL) under a nitrogen atmosphere and treated with oxalyl chloride (12.3 mL of a 2M solution in dichloromethane) and 1 drop of DMF. This suspension was stirred at room temperature for 16 h. The solvent was evaporated under reduced pressure. The residue was suspended in dichloromethane (20 mL) and poured into an ice-cold 2M solution of ammonia in methanol (122 mL). The mixture was stirred at 0° C. for 1 h, and concentrated under reduced pressure. The solid residue was washed with dichloromethane and water, and dried under high vacuum to afford benzoxazole-6-carboxamide. A portion of this material (80 mg) was dried by azeotropic distillation with toluene (5.3 mL) and treated with 3-chlorophenyl isocyanate (83.3 mg). The mixture was heated at reflux for 6 h, allowed to cool to room temperature, and treated with methanol (5 mL). The precipitated solid was collected by filtration, washed with methanol and dichloromethane, and dried under high vacuum to yield the title compound. 1H NMR (DMSO-d6) δ 7.18 (d, 1H, J=8.0 Hz), 7.39 (t, 1H, J=8.0 Hz), 7.49 (d, 1H, J=8.0 Hz), 7.86 (d, 1H, J=1.6 Hz), 7.97 (d, 1H, J=8.4 Hz), 8.09 (dd, 1H, J=8.4, 1.6 Hz), 8.50 (s, 1H), 8.98 (s, 1H), 10.90 (s, 1H), 11.24 (s, 1H). MS (ESI) m/z 314, 316.

Workup

  1. temperatureat reflux for 3 h
  2. filtrationThe precipitated solid was filtered
  3. washwashed with methanol
  4. customdried under vacuum

Sources & evidence

ORD record
ord-e305f2fae39742d99d5ebee3e4c8fcff
Source dataset
uspto-grants-2006_02
Patent number
US06998407B2

Reaction notes

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