| 摘要 |
PURPOSE: To efficiently obtain a chromenophrazole compound useful as a coloring agent for sensitive copying paper, by reacting a 2-(4'-N,N-disubstituted amino-2'-hydroxybenzoyl)benzoic acid with a 1-substituted-3-methyl-5-pyrazolone in heated sulfuric acid. CONSTITUTION: A 1-substituted-3-methyl-5-pyrazolone derivative of formula I [R<3> is H, an alkyl, benzyl or a (substituted) phenyl] (e.g. 1-phenyl-3-methyl-5- pyrazolone) is added to sulfuric acid preheated to 60-150 deg.C, reacted with a 2-(4'-N,N-disubstituted amino-2'-hydroxybenzoyl)benzoic acid of formula II [R<1> and R<2> are each an alkyl, a cycloalkyl, an alkoxy, benzyl or a (substituted) phenyl] (e.g. 2-(4'-N-ethyl-N-isoacylamino-2'-hydroxybenzoyl) benzoic acid] which is added simultaneously or previously with the addition of the raw material and colored in yellow to vermilion orange to red. The objective chromenopyrazole compound of formula II useful as a coloring agent for sensitive copying paper is obtained. |
