Iodine → 5-Ethyl-2-phenyl-oxazole-4-carboxylic acid benzyl ester

HRID 1510279Notes

Reaction equation

HRID 1510279 reaction equation
[CH2:1]([O:8][C:9](=[O:24])[CH:10]([NH:15][C:16](=[O:23])[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)[C:11](=O)[CH2:12][CH3:13])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.II.C(N(CC)CC)C>O1CCCC1>[CH2:1]([O:8][C:9]([C:10]1[N:15]=[C:16]([C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[O:23][C:11]=1[CH2:12][CH3:13])=[O:24])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

6

Reactant 4

HCID 807IodineHCID 8471TriethylamineHCID 11776TriphenylphosphineHCID 674271102-Benzoylamino-4-methyl-3-oxo-butanoic acid benzyl ester

Product 1

HCID 674272275-Ethyl-2-phenyl-oxazole-4-carboxylic acid benzyl esterYield 83.9%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

A mixture of 2-benzoylamino-4-methyl-3-oxo-butanoic acid benzyl ester (1.26 g, 3.88 mmol), triphenylphosphine (2.64 g, 10.09 mmol), and iodine (1.04 g, 8.225 mmol) in tetrahydrofuran (60 mL) was cooled to −78° C., followed by addition of triethylamine (2.18 mL, 15.52 mmol). The resulting solution was stirred at −78° C. for about 10 min, and then was warmed up to room temperature for about 1 hr. The solvent was removed and the residue was triturated with dichloromethane and filtered. The filtrate was evaporated and the residue dissolved in 70 mL of ethyl acetate, washed with 0.5 M citric acid (2×50 mL), saturated sodium bicarbonate (2×50 mL), and brine, dried over magnesium sulfate, filtered and then concentrated in vacuo. Flash chromatography (Merck silica gel 60, 230-400 mesh, 0-10% ethyl acetate in hexane) gave 5-ethyl-2-phenyl-oxazole-4-carboxylic acid benzyl ester (1 g) as a light yellow solid. LCMS calcd for C19H17NO3 (m/e) 321, obsd 322 (M+H).

Workup

  1. temperaturewas warmed up to room temperature for about 1 hr
  2. customThe solvent was removed
  3. customthe residue was triturated with dichloromethane
  4. filtrationfiltered
  5. customThe filtrate was evaporated
  6. dissolutionthe residue dissolved in 70 mL of ethyl acetate
  7. washwashed with 0.5 M citric acid (2×50 mL), saturated sodium bicarbonate (2×50 mL), and brine
  8. dry with materialdried over magnesium sulfate
  9. filtrationfiltered
  10. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-934cf748d57a4d75acce5b52bc7322c8
Source dataset
uspto-grants-2012_07
Patent number
US08211914B2

Reaction notes

Loading…