| abstract |
(57) [Problem] In a method for producing a phthalide compound useful as a color former of a color-forming recording material by an oxidation reaction of a leuco compound, the reaction proceeds rapidly, and a high purity and a high yield can be obtained. To provide a manufacturing method. [PROBLEMS] General formula (1) [In the formula (1), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 represents an alkyl group; R 1 , R 2 , R 3 and R 4 and R 5 and R 6 are linked to each other, A heterocyclic ring may be formed together with the nitrogen atom. In the production of the phthalide compound represented by the general formula (2): [In the formula (2), R 1 to R 6 are the same as those in the formula (1). Is carried out in an aqueous solvent in the presence of activated carbon when performing an oxidation reaction with an oxidizing agent. |