Ethyl hexanoate → 7-Butyl-8-hydroxy-5-phenylpyrido[2,3-b]pyrazin-6(5H)-one

Reaction equation

[C:1]1([NH:7][C:8]2[C:13]([C:14]([O:16]C)=O)=[N:12][CH:11]=[CH:10][N:9]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[C:18](OCC)(=[O:24])[CH2:19][CH2:20][CH2:21][CH2:22][CH3:23].CC(C)([O-])C.[K+]>>[CH2:20]([C:19]1[C:18](=[O:24])[N:7]([C:1]2[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=2)[C:8]2=[N:9][CH:10]=[CH:11][N:12]=[C:13]2[C:14]=1[OH:16])[CH2:21][CH2:22][CH3:23]

Participants

Reactant 3

HCID 31265Ethyl hexanoate

HCID 13370930Methyl 3-anilinopyrazine-2-carboxylate

HCID 23665647Potassium tert-butoxide

Product 1

HCID 546800437-Butyl-8-hydroxy-5-phenylpyrido[2,3-b]pyrazin-6(5H)-one

Procedure

A mixture of 3.5 g. of methyl 2-phenylamino-3pyrazine carboxylate, 30 ml. of ethyl caproate and 4 g. of potassium tertiary butoxide is stirred and heated under nitrogen at 150°-160° for one and a half hours. The reaction mixture is poured on ice, extracted with ethyl acetate and the ethyl acetate extracts washed with water. The combined aqueous layers are acidified to pH 5.5 with dilute hydrochloric acid and the solid filtered. Recrystallization from ethyl acetate-hexane yields the product of this example as a colorless solid; m.p. 183°-185° C.