| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject compound, providing a colored image manifesting storing absorption in a near infrared region of 590-750nm, having shelf life equal to or better than that of a conventional leuco coloring matter and useful as an electron donative leuco coloring matter. SOLUTION: This 3-[4-(N-ethyl-N-p-tolylamino)-2-ethoxyphenyl]-3-[1,1-bis(p- diethylaminophenyl)ethylen-2yl]phthalide is represented by the formula. The compound represented by the formula can be obtained as a white crystal by discharging a reactional product of ortho(4-(N-ethyl-N-p-tolylamino)-2- ethoxybenzoyl)benzoic acid with 1,1-bis(p-diethylaminophenyl)ethylene and acetic anhydride into water/toluene, neutralizing the reactional product with NaOH, then separating and collecting a toluene layer, distilling off the toluene, thermally dissolving the residual tar in acetonitrile, subsequently allowing the solution to cool and filtering the cooled solution. |
