| 摘要 |
PURPOSE:To reduce ground fogging of a recording material and markedly reduce fogging generated during preservation and a lowering of a color development performance with time, by using a specified spiro compound excellent as a coloring matter precursor. CONSTITUTION:A spiro compound of formula I is used in a recording material which provides a colored body on contact with an acid. The spiro compound can be synthesized by a method wherein a compound of formula II is treated with a chlorinating reagent such as phosphorus pentachloride, phosphorus oxychloride or thionyl chloride, and the resultant compound is brought into reaction with a bezoic acid having an amine residue at the meta-position or a derivative thereof. The spiro compound is a colorless or light-colored crystal, has a high solubility to organic solvents, and speedily develops a color when being brought into contact with an electron-acceptive substance. Thus developed coloring matter is extremely stable as compared with a coloring matter formed from a color former, and it hardly undergoes discoloration or decoloration even when being irradiated with light for a long period of time or being subjected to heat or moisture. In the formulas, each of R1 and R2 is H, halogen, alkyl, alkoxy, nitro or the like, R3 is an amine residue, and Y is a group required for forming a 6-membered ring consisting of non-metallic atoms. |
