Ethyl orthoformate → 7-chloro-3-ethyl-5-methyl-3H-imidazo[4,5-b]pyridine-6-carboxylic acid, ethyl ester
Reaction equation
[NH2:1][C:2]1[C:3]([Cl:17])=[C:4]([C:12]([O:14][CH2:15][CH3:16])=[O:13])[C:5]([CH3:11])=[N:6][C:7]=1[NH:8][CH2:9][CH3:10].[CH2:18](OC(OCC)OCC)C>>[Cl:17][C:3]1[C:4]([C:12]([O:14][CH2:15][CH3:16])=[O:13])=[C:5]([CH3:11])[N:6]=[C:7]2[N:8]([CH2:9][CH3:10])[CH:18]=[N:1][C:2]=12Participants
3
Procedure
25.7 g. of 5-amino-6-ethylamino-4-chloro-2-methylpyridine-3-carboxylic acid, ethyl ester (0.1 mol.) is refluxed for 12 hours with 100 ml. of orthoformic acid triethyl ester with stirring. The excess ester is removed in vacuo and the oily residue distilled to obtain 7-chloro-3-ethyl-5-methyl-3H-imidazo[ 4,5-b]pyridine-6-carboxylic acid, ethyl ester, b.p. 195° 0.01. Yield 23 g. (86%).
Workup
- customThe excess ester is removed in vacuo
- distillationthe oily residue distilled