1,2-Benzenedicarboxylic acid, 4-nitro- → 4-Aminophthalic acid

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Reaction Steps

124.9 g (0.69 mol) of 4-aminophthalic acid freshly obtained by reduction of 4-nitrophthalic acid in dioxane are reacted with 109.8 g (0.72 mol) of cis-1,2,3,6-tetrahydrophthalic anhydride in the manner described in Example 9, and the product is worked up as follows: after the batch has stood for 20 hours, the clear reaction solution is concentrated in vacuo to approx. 200 ml and heated with 200 ml of acetic anhydride and 170 ml of pyridine to 60° C. for 10 hours. The solvents are then stripped off in vacuo and the solid residue is recrystallised from benzene, whereupon the yellow-coloured phthalic anhydride derivative is obtained in a yield of about 50%, melting point = 188° C.

Provenance & Evidence