| 摘要 |
PURPOSE:To obtain a crystal of the subject compound capable of improving solubility in capsule oils and performance of heat-sensitive recording sheets such as preservation stability or coloring characteristics. CONSTITUTION:A crystal of a compound expressed by formula I [R<1> is i-C3H7, sec-C4H9), e.g. 3-N-isopropyl-N-propylamino-6-methyl-7-anilinofluoran. The crystal of the compound expressed by formula I is obtained by reacting, e.g. a compound expressed by formula II (R2 is same as R) with a compound expressed by formula III (R3 is 1-4C alkyl) in the presence of a dehydration condensing agent containing concentrated sulfuric acid or fuming sulfuric acid added thereto at 0-100 deg.C (preferably 0-50 deg.C), then regulating the resultant compound to pH 9-12 with potassium hydroxide, etc., treating the regulated compound with an alkali at 0-100 deg.C and subsequently separating and isolating the objective compound with an organic solvent having <=50wt.% moisture content. |
