Acetyl chloride → Methyl 7-bromo-2-methylbenzo[d]oxazole-4-carboxylate

HRID 1505251Notes

Reaction equation

HRID 1505251 reaction equation
[CH3:1][O:2][C:3](=[O:13])[C:4]1[CH:9]=[CH:8][C:7]([Br:10])=[C:6]([OH:11])[C:5]=1[NH2:12].[CH2:14](N(CC)CC)[CH3:15].C1(C)C=CC(S([O-])(=O)=O)=CC=1.[NH+]1C=CC=CC=1.C(Cl)(=O)C>C1(C)C=CC=CC=1.Cl.C(OCC)(=O)C>[CH3:1][O:2][C:3]([C:4]1[CH:9]=[CH:8][C:7]([Br:10])=[C:6]2[O:11][C:14]([CH3:15])=[N:12][C:5]=12)=[O:13]

Participants

8

Reactant 4

HCID 6367Acetyl chlorideHCID 8471TriethylamineHCID 466102Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1)HCID 58498018Methyl 2-amino-4-bromo-3-hydroxybenzoate

Product 1

HCID 58497951Methyl 7-bromo-2-methylbenzo[d]oxazole-4-carboxylate

Reagents, catalysts & solvents 3

HCID 313Hydrochloric AcidSolventHCID 1140TolueneSolventHCID 8857Ethyl AcetateSolvent

Procedure

To a solution of 2-amino-4-bromo-3-hydroxy-benzoic acid methyl ester (Example 6.3) (2.46 g) in toluene (250 ml) was added sequentially triethylamine (1.53 ml), pyridinium p-toluenesulfonate (“PPTS”) (0.75 g) and acetyl chloride (0.78 ml). The reaction mixture was heated at reflux for 16 hours. The reaction mixture was cooled to ambient temperature and diluted with aqueous hydrochloric acid (1M) (100 ml) and ethyl acetate (200 ml). The phases were separated and the organic extract was washed with aqueous hydrochloric acid (1M) (150 ml) and brine (150 ml) and then dried over sodium sulfate. The solids were removed by filtration and the filtrate was concentrated to give 7-bromo-2 methyl-benzo[d]oxazole-4-carboxylic acid methyl ester (2.94 g). 1H-NMR (400 MHz, CDCl3): 7.87 (d, 1H), 7.52 (d, 1H), 4.04 (s, 3H), 2.77 (s, 3H) ppm.

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureat reflux for 16 hours
  3. customThe phases were separated
  4. extractionthe organic extract
  5. washwas washed with aqueous hydrochloric acid (1M) (150 ml) and brine (150 ml)
  6. dry with materialdried over sodium sulfate
  7. customThe solids were removed by filtration
  8. concentrationthe filtrate was concentrated

Sources & evidence

ORD record
ord-e8a3838c09d84300b067f14c9b53b7b7
Source dataset
uspto-grants-2015_12
Patent number
US09216973B2

Reaction notes

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