Sodium Bicarbonate → 2-tert-Butyl-5-methyl-oxazole-4-carboxylic acid methyl ester

HRID 1897559Notes

Reaction equation

HRID 1897559 reaction equation
O=[C:2]([CH3:15])[CH:3]([NH:8][C:9](=[O:14])[C:10]([CH3:13])([CH3:12])[CH3:11])[C:4]([O:6][CH3:7])=[O:5].C([O-])(O)=O.[Na+]>P(Cl)(Cl)(Cl)=O>[C:10]([C:9]1[O:14][C:2]([CH3:15])=[C:3]([C:4]([O:6][CH3:7])=[O:5])[N:8]=1)([CH3:13])([CH3:12])[CH3:11]

Participants

4

Reactant 2

HCID 516892Sodium BicarbonateHCID 57659743Methyl 3-oxo-2-(pivalamido)butanoate

Product 1

HCID 576597452-tert-Butyl-5-methyl-oxazole-4-carboxylic acid methyl esterYield 22.3%

Reagents, catalysts & solvents 1

HCID 24813Phosphorus oxychlorideSolvent

Procedure

A solution of methyl 3-oxo-2-(pivalamido)butanoate (0.22 g, 1.0 mmol) in phosphorus oxychloride (1.5 mL) was heated at 110° C. for 30 min. The reaction was cooled in an ice bath, and saturated aqueous NaHCO3 was slowly added until the mixture was basic. The reaction was extracted with CH2Cl2, and the extracts were washed with saturated aqueous NaHCO3 and water, dried over Na2SO4, and concentrated under vacuum. The residue was purified by silica gel chromatography (0%-40% EtOAc-hexanes) to obtain methyl 2-tert-butyl-5-methyloxazole-4-carboxylate (44 mg, 22% yield). 1H NMR (400 MHz, CDCl3) δ 3.90 (s, 3H, 2.60 (s, 3H), 1.39 (s, 9H) ppm. LC/MS: m/z 198.3 (M+H)+ at 2.83 min (10%-99% CH3CN (0.035% TFA)/H2O (0.05% TFA)).

Workup

  1. temperatureThe reaction was cooled in an ice bath
  2. extractionThe reaction was extracted with CH2Cl2
  3. washthe extracts were washed with saturated aqueous NaHCO3 and water
  4. dry with materialdried over Na2SO4
  5. concentrationconcentrated under vacuum
  6. customThe residue was purified by silica gel chromatography (0%-40% EtOAc-hexanes)

Sources & evidence

ORD record
ord-7b5e08e9715344e1963db9e7ce28e2d1
Source dataset
uspto-grants-2013_08
Patent number
US08519137B2

Reaction notes

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