| 摘要 |
NEW MATERIAL:A leuco dye compound of formula I [wherein R1-4 are each a lower alkyl, R5 is alpha- or beta-naphthyl, a group of formula II (wherein R6 is a group of formula III, a halogen or a substituted amino and R9 is H or R1), R7-8 are each R9, and R6 is a group of formula III when both of R7 and R8 are H atoms]. EXAMPLE:A compound of formula IV. USE:A leuco dye useful as a colorant precursor in the form of a white to light yellow crystalline powder which when brought into contact with an electron- accepting compound (color developer) on a molecular level, forms a green to blue heat-sensitive or pressure-sensitive recording colorant of excellent storage stability, excels in stability in air and shows strong absorptions in the near- infrared region at 600-1,000nm. PREPARATION:A compound of formula V (wherein X<-> is an anion such as a halide or perchlorate ion) is reacted with a compound of formula IV by heating in a methanol/acetic acid solvent. |
