| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject compound useful as a color former capable of producing a heat-sensitive recording material manifesting excellent background whiteness degree, color fastness to light, moisture resistance, etc., by providing the compound with characteristics indicated by a specific X-ray powder diffraction pattern. SOLUTION: This compound represented by formula I is characterized by an X-ray powder diffraction pattern having high peaks at 6.31, 12.37, 12.83, 17.02, 17.33, 18.10 and 18.30 diffraction angles 2θ. The compound is obtained by reacting 2'-carboxy-4-dimethylamino-2-hydroxybenzophenone with a compound represented by formula II (R1 is H or the like) (e.g. 4-methoxy-2- methyldiphenylamine) in the presence of a dehydration condensing agent such as concentrated sulfuric acid, preferably at about 10-60 deg.C for several hr to 100 hr, treating the resultant fluoran compound with an alkali such as sodium hydroxide in an organic solvent such as toluene and then isolating the prepared compound. |
