Phenothiazine → 1-Methyl-1,2-cyclohexanedicarboxylic acid

Beteiligte Stoffe

Reaktionsschritte

2.35 g (0.005 mol) of the diketopyrrolopyrrole of the formula XIX (Example 6) and 30 ml of dichlorobenzene are placed under nitrogen in a sulfonating flask, 5.0 mg (0.05 mmol) of thiodiphenylamine are added, and the mixture is heated with stirring at 110°-115° C. 3.17 g (0.010 mol) of the methyl-hexahydrophthalic acid derivative (isomer mixture) of the formula ##STR43## (obtained by generally known methods from methylhexahydrophthalic anhydride and hydroxyethyl methacrylate) are added dropwise with vigorous stirring over the course of 15 minutes to the clear orange-red solution, stirring is continued for about 2 hours at 110°-115° C., and then the mixture is cooled to room temperature. The clear dark red solution is washed in a separating funnel 3 times with 20 ml of 5% sodium hydroxide solution and 2 times with 30 ml of deionized water, and the organic phase is dried over MgSO4 ·H2O, filtered and concentrated to dryness under a high vacuum. The resulting product is recrystallized from 30 ml of ethanol, to give 3.05 g (81.3% of theory) of a crystalline product of the formula ##STR44## with a melting point of 69.6° C.

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