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

Reaktionsgleichung

[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]

Komponenten

Edukt 3

HCID 6101p-Toluenesulfonic acid

HCID 66995Ethyl orthopropionate

HCID 19958246Diethyl 5-amino-1,6-dihydro-6-oxo-2,3-pyridinedicarboxylate

Produkt 1

HCID 19958240Diethyl 2-ethyloxazolo[5,4-b]pyridine-5,6-dicarboxylateAusbeute 84,8 %

Versuchsvorschrift

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 triethyorthopropionate is removed in vacuo and the resulting oil is purified by column chromatography. The tractions containing the pure desired product are combined and striped to a honey-colored oil weighing 7.38 g, yield 84.8%.