Water → Ethyl 5-tert-butyl-1,3-oxazole-2-carboxylate

HRID 1870085Notes

Reaction equation

HRID 1870085 reaction equation
P(Cl)(Cl)(Cl)=O.[CH2:6]([O:8][C:9](=[O:20])[C:10]([NH:12][CH2:13][C:14](=[O:19])[C:15]([CH3:18])([CH3:17])[CH3:16])=O)[CH3:7].O>C1(C)C=CC=CC=1>[CH2:6]([O:8][C:9]([C:10]1[O:19][C:14]([C:15]([CH3:18])([CH3:17])[CH3:16])=[CH:13][N:12]=1)=[O:20])[CH3:7]

Participants

5

Reactant 3

HCID 962WaterHCID 24813Phosphorus oxychlorideHCID 11241370Ethyl[(3,3-dimethyl-2-oxobutyl)amino](oxo)acetate

Product 1

HCID 11788834Ethyl 5-tert-butyl-1,3-oxazole-2-carboxylateYield 58%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

Phosphorus oxychloride (16.3 ml, 0.178 mol) is added to a stirred solution of N-(3.3-dimethyl-2-oxo-butyl) oxalamic acid ethyl ester (38.4 g, 0.178 mol) in toluene (p150 ml). The mixture is heated gradually to reflux, and then refluxed for 16 h. After cooling, the mixture is added portionwise to water (500 ml) and stirred vigorously. The organic phase is separated and washed thoroughly with saturated sodium hydrogen carbonate solution (500 ml) and then twice with water (500 ml). The organic phase is then dried over sodium sulfate and evaporated in vacuo. The residue is purified by flash column chromatography (silica gel, petroleum ether/ethyl acetate 7:3 v/v) to give 5-tert-butyl-oxazole-2-carboxylic acid ethyl ester (20.23 g, 58%) as an oil.

Workup

  1. temperatureThe mixture is heated gradually
  2. temperatureto reflux
  3. temperaturerefluxed for 16 h
  4. temperatureAfter cooling
  5. customThe organic phase is separated
  6. washwashed thoroughly with saturated sodium hydrogen carbonate solution (500 ml)
  7. dry with materialThe organic phase is then dried over sodium sulfate
  8. customevaporated in vacuo
  9. customThe residue is purified by flash column chromatography (silica gel, petroleum ether/ethyl acetate 7:3 v/v)

Sources & evidence

ORD record
ord-29e8c138b224421ea67186dfac1580d6
Source dataset
uspto-grants-2000_08
Patent number
US06096688

Reaction notes

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