p-Toluenesulfonic acid → Diethyl 2-ethyloxazolo[5,4-b]pyridine-5,6-dicarboxylate

HRID 1898850Notes

Reaction equation

HRID 1898850 reaction equation
[NH2:1][C:2]1[C:7](=[O:8])[NH:6][C:5]([C:9]([O:11][CH2:12][CH3:13])=[O:10])=[C:4]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[CH:3]=1.C(O[C:22](OCC)(OCC)[CH2:23][CH3:24])C.C1(C)C=CC(S(O)(=O)=O)=CC=1>>[CH2:23]([C:24]1[O:8][C:7]2[C:2]([N:1]=1)=[CH:3][C:4]([C:14]([O:16][CH2:17][CH3:18])=[O:15])=[C:5]([C:9]([O:11][CH2:12][CH3:13])=[O:10])[N:6]=2)[CH3:22]

Participants

4

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 66995Ethyl orthopropionateHCID 19958246Diethyl 5-amino-1,6-dihydro-6-oxo-2,3-pyridinedicarboxylate

Product 1

HCID 19958240Diethyl 2-ethyloxazolo[5,4-b]pyridine-5,6-dicarboxylateYield 84.8%

Procedure

Diethyl 5-amino-1,6-dihydro-6-oxo-pyridine-2,3-dicarboxylate (7.57 g, 0.030 mol), is suspended in 60 mL triethylorthopropionate (TEOP 0.30 mol). A small amount of p-toluenesulfonic acid is added and the mixture is heated at reflux for 65 hours. The triethylorthopropionate is removed in vacuo and the resulting oil is purified by column chromatography. The tractions containing the pure desired product are combined and stripped to a honey-colored oil weighing 7.38 g, yield 84.8%.

Workup

  1. temperaturethe mixture is heated
  2. temperatureat reflux for 65 hours
  3. customThe triethylorthopropionate is removed in vacuo
  4. customthe resulting oil is purified by column chromatography
  5. additionThe tractions containing the pure desired product

Sources & evidence

ORD record
ord-b7b08bd2e9d64f71b15fdc58cdc7935e
Source dataset
uspto-grants-1996_11
Patent number
US05571773

Reaction notes

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