2-Amino-4-methylpyridine → 4-Methyl-2-phthalimidopyridine

Reaction equation

[CH3:1][C:2]1[CH:7]=[CH:6][N:5]=[C:4]([NH2:8])[CH:3]=1.[C:9]1(=O)[O:14][C:12](=[O:13])[C:11]2=[CH:15][CH:16]=[CH:17][CH:18]=[C:10]12.C(OC(=O)C)(=O)C>C(O)(=O)C>[CH3:1][C:2]1[CH:7]=[CH:6][N:5]=[C:4]([N:8]2[C:12](=[O:13])[C:11]3=[CH:15][CH:16]=[CH:17][CH:18]=[C:10]3[C:9]2=[O:14])[CH:3]=1

Participants

Procedure

To a stirring solution of 4-methyl-2-aminopyridine (50 g, 460 mmol) in acetic acid (1 L) was added phthalic anhydride (68 g, 460 mmol) and the reaction was heated to reflux. After 12 h, acetic anhydride (43 mL, 460 mmol) was added and the solution continued to stir at reflux for an additional 48 h. The solvent was then removed in vacuo and the solid residue was suspended in toluene and concentrated in vacuo twice. The solid was then suspended in ethyl acetate with vigorous stirring and filtered. After repeating this ethyl acetate washing procedure the solid was dried overnight in vacuo to give 46.6 g (42%) of a white solid.