| 摘要 |
Chromogenic compounds of colorless or lightly colored form are disclosed having the following structural formula:wherein E represents a six-membered aromatic or heterocyclic ring which may have an aromatic condensed ring and both the E ring and the condensed ring may be substituted.Each of R1, R2, R3 and R4 independently represents hydrogen, alkyl of not more than 12 carbon atoms which is unsubstituted or substituted by halogen, hydroxyl, cyano or lower alkoxy or represents cycloalkyl, phenyl, benzyl, or phenyl or benzyl which is substituted by halogen, lower alkyl or lower alkoxy or R1 and R2 or R3 and R4 together with the nitrogen atom to which they are attached represent a 5- or 6-membered heterocyclic radical.Each of R7 and R8 independently represents hydrogen, lower alkyl, lower alkoxy or halo.The compounds of this invention are eligible for use in pressure-sensitive and heat-sensitive record materials and manifold marking systems.
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