| abstract |
PURPOSE:To provide fluoran compds. which have a specified structural formula, form black color by the action of a developer, whose developed dye absorbs electromagnetic waves in the wavelength region of near-infrared rays and which are useful as the color forming components of a color forming recording medium. CONSTITUTION:Fluoran compds. of formula I. In the formula, R1 and R2 are independently H, an alkyl, a cycloalkyl or benzyl group, or R1 and R2 may be combined together with the neighboring nitrogen atom to form a pyrrolidino, piperidino or morpholino group; R3 and R4 are independently H, an alkyl, phenyl or benzyl group; the ring A is a benzene or naphthalene ring which may be substituted; the rings B, C and D may be substituted with a halogen, an alkyl or an alkoxy group. |