3,4-Diaminopyridine → HCID 178488902, compound
Reaction equation
[NH2:1][C:2]1[CH:3]=[N:4][CH:5]=[CH:6][C:7]=1[NH2:8].[CH3:9][O:10][C:11]1[CH:19]=[C:18]([O:20][CH3:21])[CH:17]=[CH:16][C:12]=1[C:13](O)=O.P(Cl)(Cl)([Cl:24])=O>>[ClH:24].[CH3:9][O:10][C:11]1[CH:19]=[C:18]([O:20][CH3:21])[CH:17]=[CH:16][C:12]=1[C:13]1[NH:8][C:7]2[CH:6]=[CH:5][N:4]=[CH:3][C:2]=2[N:1]=1Participants
4
Procedure
A mixture of 3,4-diaminopyridine (10.90 g., 100 mmoles) and 2,4-dimethoxybenzoic acid (18.20 g., 100 mmoles) was added to 400 ml. of phosphorous oxychloride and the resulting mixture was heated to reflux for about 4 hours. After cooling, the excess phosphorous oxychloride was removed under reduced pressure and the residue was treated with 200 ml. of 1N hydrochloric acid. The resulting solution was neutralized with 50% aqueous sodium hydroxide and the precipitated product was collected by filtration. Flash chromatography over silica gel (methylene chloride/methanol, 15:1) and recrystallization from ethanol/water saturated with hydrogen chloride gave the title product (16.54 g., 57% yield) as light tan needles, m.p. about 231°-234° C.