3-Methoxybenzoic Acid → 2-Phenyl-1,3-oxazole

HRID 1656418Notes

Reaction equation

HRID 1656418 reaction equation
[C:1]([OH:11])(=O)[C:2]1[CH:7]=[CH:6][CH:5]=[C:4](OC)[CH:3]=1.C1CN2[C:14](=[N:15]CCC2)[CH2:13]1.C1C=CC(P(N=[N+]=[N-])(C2C=CC=CC=2)=O)=CC=1>CN(C=O)C.[Cl-].[NH4+]>[C:2]1([C:1]2[O:11][CH:13]=[CH:14][N:15]=2)[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

6

Reactant 3

HCID 114613-Methoxybenzoic AcidHCID 763491,5-Diazabicyclo(4.3.0)non-5-eneHCID 199401P,P-Diphenylphosphinic azide

Product 1

HCID 5892802-Phenyl-1,3-oxazoleYield 92.7%

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 25517Ammonium ChlorideSolvent

Procedure

To a mixture of methyl isooyanoacetate (7.1 g, 171 mmol), m-anisic acid (26 g, 171 mmol) and DBN (78 mL, 522 mmol) dissolved in DMF (1.1 L), was added DPPA (37 mL, 171 mmol) by dropwise addition. The reaction mixture was stirred about 18 hours, diluted with 50% saturated ammonium chloride solution (1 vol), extracted with diethyl ether, and the organic layers washed with water and brine before drying over MgSO4. Concentration and recrystallization (diethyl ether/hexanes) gave 24 23 g (58%), mp 75°-76° C. IR (KBr, cm-1) 3110, 3066, 1712, 1604, 1590, 1560, 1516, 1488, 1472, 1456, 1432, 1346, 1314, 1254, 1209, 1170, 1110, 1093, 1036, 892, 850, 786, 646. 1H NMR (300 MHz, CDCl3)δ 3.84 (3H, s), 3.92 (3H, s , 6.99 (1H, dd, J=8.1 Hz, J=2.I Hz) 7.36 (1 H, t, J=8.l Hz), 7.63 (1H, m), 7.72 (1H, Br.s), 7.88 (1H, s). 13C NMR (75 MHz, CDCl3) ppm 52.58, 55.60, 113.66, 116.97, 120.87, 126.66, 127.87, 129.76, 149.08, 155.61, 159.69, 165.54. m/e 234 (MH+).

Workup

  1. additionTo a mixture of methyl
  2. additionby dropwise addition
  3. extractionextracted with diethyl ether
  4. washthe organic layers washed with water and brine
  5. dry with materialbefore drying over MgSO4
  6. concentrationConcentration and recrystallization (diethyl ether/hexanes)

Sources & evidence

ORD record
ord-a61b6b8e61c946d8a1292fb706b232aa
Source dataset
uspto-grants-1993_10
Patent number
US05254576

Reaction notes

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