| abstract |
(57) [Summary] [Purpose] 3-methyl-, which is important as a photographic dye intermediate It is an inexpensive and stable supply of a 2,4-pentadienylidene derivative without using a toxic reagent. [Constitution] 2,4-dinitrochlorobenzene was added to pKa A method for producing a specific quaternary salt, which comprises reacting with 4-picoline in the presence of a carboxylic acid at 25 ° = 2.5 to 5.0, and reacting the quaternary salt with aniline or a derivative thereof. A method for producing a pentamethine compound, which comprises: |