METHOD OF OBTAINING DIALKYL ETHERS OF 4,5-DICYANOPHTHALIC ACID Russian patent published in 2014 - IPC C07C255/55 C07C253/20 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of obtaining dialkyl ethers of 4,5-dicyanophthalic acid of formula given below, which can be applied as initial compounds for obtaining 2,3,9,10,16,17,23,24-octacarbalkoxy- and 2,3,9,10,16,17,23,24- octa-carboxy phthalocyanines, applied for photodynamic, sonodynamic and catalytic therapy of oncologic diseases. The method includes stages of disclosing an imide cycle of 4,5-dicarbalkoxyphthalimide with obtaining an ether of 4,5-dicarbamoylphthalic acid with its following dehydration to a respective dialkyl ether of 4,5-dicyanophthalic acid. As an initial product applied is pyromellitic acid, which is converted into 4,5-dicarboxyphthalimide by the interaction with water ammonia with the following heating of the obtained salt to 260-270°C. Then, 4,5-dicarboxyphthalimide is etherified with the formation of 4,5-dicarbalkoxyphthalimide.

EFFECT: method makes it possible to obtain dialkyl ethers of 4,5-dicyanophthalic acid with a good output without additional purifications of intermediate and end products.

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