| 摘要 |
NEW MATERIAL:A compound shown by formula I {L is (substituted) methine, trimethine formed by bonding methines by conjugated double bond or pentamethine; E is O, S or N-R<4> [R<1> and R<4> are (substituted)alkyl or (substituted) alkenyl; R<2> is (substituted)alkyl or (substituted)alkynyl; R<3> is H, halogen, cyano, nitro, OH, (substituted)alkyl or (substituted)aryl}. USE:Useful as an optical information recording medium, photographic sensitized material (for preventing halation and irradiation especially in photographic sensitized material of silver halide), optical filtration and coloring composition for heat-sensitve paper. Having an absorption band in a wide wavelength range reaching a near infrared range. PREPARATION:A dioxopyrazolopyridine compound shown by formula II is reacted with a proper methine source, trimethine source or pentamethine source compound in a solvent such as methanol. |
