Sodium Hydroxide → Ethyl 4-ethyloxazole-5-carboxylate

HRID 1109990Notes

Reaction equation

HRID 1109990 reaction equation
Cl[CH:2]([C:8](=O)[CH2:9][CH3:10])[C:3]([O:5][CH2:6][CH3:7])=[O:4].[CH:12]([O-:14])=O.[NH4+:15].[OH-].[Na+]>C(O)=O.O.C(OCC)C>[CH2:9]([C:8]1[N:15]=[CH:12][O:14][C:2]=1[C:3]([O:5][CH2:6][CH3:7])=[O:4])[CH3:10]

Participants

7

Reactant 3

HCID 14798Sodium HydroxideHCID 2723923Ammonium formateHCID 12923424Ethyl 2-chloro-3-oxopentanoate

Product 1

HCID 19018567Ethyl 4-ethyloxazole-5-carboxylateYield 40.4%

Reagents, catalysts & solvents 3

HCID 284Formic AcidSolventHCID 962WaterSolventHCID 3283Diethyl EtherSolvent

Procedure

Ethyl 2-chloro-3-oxopentanoate (29.2 g, 0.164 mol) prepared by the method of E. A. Falco, P. B. Russell and G. H. Hitchings, J. Am. Chem. Soc 1951, 73, 3753, and ammonium formate (60 g, 0.95 mol ) were heated in 100% formic acid (180 ml ) under reflux for 5 h. The cooled mixture was diluted with water (300 ml) and diethyl ether (200 ml), then neutralised with aqueous sodium hydroxide (5M). The layers were separated and the aqueous layer extracted with more ether (4×200 ml). The combined ether layers were dried over magnesium sulphate and the solvent removed by distillation at atmospheric pressure. Vacuum distillation of the residue yielded the desired oxazole (11.2 g, 40%) b.p. 100°-106° (7 mm). This was contaminated with starting material. An analytical sample, obtained by extracting into 5M sulphuric acid, had b.p. 97°-98° (7 mm) . (Found C, 56.64; H, 6.63; N, 8.24; C8H11NO3 requires: C, 56.80; H, 6.55; N, 6.28%); m/e 169 (M+); δ (360 MHz, CDCl3) 1.27 (3H, J=7.5 Hz, ArCH2CH3); 1.40 (3H, t, J=7 Hz, CO2CH2CH3); 2.91 (2H, q, J=7.5 Hz, arCH2CH3); 4.40 (2H, q, J=7 Hz, CO2CH2CH3); 7.89 (1H, s, ArH).

Workup

  1. temperatureunder reflux for 5 h
  2. customThe layers were separated
  3. extractionthe aqueous layer extracted with more ether (4×200 ml)
  4. dry with materialThe combined ether layers were dried over magnesium sulphate
  5. customthe solvent removed by distillation at atmospheric pressure
  6. distillationVacuum distillation of the residue

Sources & evidence

ORD record
ord-0ac23579390a45aa9d1445c18952bf24
Source dataset
uspto-grants-1994_06
Patent number
US05324723

Reaction notes

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