Uses
Pyridine-3,4-dicarboxylic anhydride is an important organic intermediate. It is used in agrochemical, pharmaceutical and dyestuff field.
Synthesis
The general procedure for the synthesis of pyridine-3,4-dicarboxylic anhydride from 3,4-pyridinedicarboxylic acid is as follows: in a 1 L round-bottomed flask fitted with a drying tube, 3,4-pyridinedicarboxylic acid (160 g, 1 mol) and acetic anhydride (500 mL) were added. The reaction mixture was refluxed in an oil bath at 165°C for 2 hours. Upon completion of the reaction, decompression concentration was carried out to remove excess acetic anhydride. After cooling, a residual oily substance was obtained. Methyl tert-butyl ether (500 mL) was added to the residue and stirred overnight at room temperature. Subsequently, a dark brown solid precipitate precipitated and was separated by filtration. The filter cake was washed with 100 mL of methyl tert-butyl ether (MTBE) and dried under vacuum at 45°C to give 99 g of solid product in 76% yield.
References
[1] Journal of Organic Chemistry, 1992, vol. 57, # 22, p. 5891 - 5899
[2] Journal of Medicinal Chemistry, 1994, vol. 37, # 6, p. 828 - 837
[3] Patent: EP503537, 1992, A1
[4] Patent: CN104557704, 2017, B. Location in patent: Paragraph 0042; 0043; 0044
[5] Monatshefte fuer Chemie, 1890, vol. 11, p. 144
