Triethylamine → 2-(Isocyanomethyl)benzoxazole

HRID 1378724Notes

Reaction equation

HRID 1378724 reaction equation
[CH:1]([NH:3][CH2:4][C:5]1[O:6][C:7]2[CH:13]=[CH:12][CH:11]=[CH:10][C:8]=2[N:9]=1)=O.C(N(CC)CC)C.P(Cl)(Cl)(Cl)=O.C(=O)([O-])[O-].[Na+].[Na+]>ClCCl.O>[N+:3]([CH2:4][C:5]1[O:6][C:7]2[CH:13]=[CH:12][CH:11]=[CH:10][C:8]=2[N:9]=1)#[C-:1]

Participants

7

Reactant 4

HCID 8471TriethylamineHCID 10340Sodium CarbonateHCID 24813Phosphorus oxychlorideHCID 229128102-(N-Formylaminomethyl)benzoxazole

Product 1

HCID 229128942-(Isocyanomethyl)benzoxazole

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6344DichloromethaneSolvent2×

Procedure

To 2.83 g (16.1 mmol) of 2-(N-formylaminomethyl)benzoxazole, 7.39 ml (53.0 mmol) of triethylamine, and 30 ml of dichloromethane stirred at 0° are added dropwise 2.71 g (17.7 mmol) of phosphorous oxychloride in 5 ml of dichloromethane. The reaction mixture is stirred at 0° for 45 min and then 2.81 g of sodium carbonate dissolved in 20 ml of water is added. The mixture is stirred for 30 min and then partitioned between dichloromethane and aq. sodium bicarbonate. The organic layers are dried over sodium sulfate and concentrated and the crude product is chromatographed on silica gel (325 ml) eluting with ethyl acetate/hexane (10/90), the appropriate fractions are pooled and concentrated to give the title compound, mp 57.0°-57.5°; MS (m/z) at 158; IR 766, 2166, 987, 1167 and 1230 cm-1 ; NMR (CDCl3) 4.94, 7.42, 7.58 and 7.76 δ.

Workup

  1. additionis added
  2. stirringThe mixture is stirred for 30 min
  3. custompartitioned between dichloromethane and aq. sodium bicarbonate
  4. dry with materialThe organic layers are dried over sodium sulfate
  5. concentrationconcentrated
  6. customthe crude product is chromatographed on silica gel (325 ml)
  7. washeluting with ethyl acetate/hexane (10/90)
  8. concentrationconcentrated

Sources & evidence

ORD record
ord-419f2f6bff3c40918496bc4a4b2866f2
Source dataset
uspto-grants-1997_09
Patent number
US05668282

Reaction notes

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