| 摘要 |
PROBLEM TO BE SOLVED: To enhance photochromic characteristics, to increase fading speed and to suppress initial coloring by using a specified chromene compound. SOLUTION: The chromene compound is represented by the formula, wherein R1 is substituted amino, an optionally substituted heterocyclic group having a nitrogen atom bonding to the naphthopyran ring as a heteroatom or the like, R2-R4 are each H, substituted amino, an optionally substituted heterocyclic group having a nitrogen atom bonding to the adjacent benzene ring as a heteroatom or the like, R5 and R7 are each H, halogen or the like, R6 is H, alkoxy or the like, R8 is alkyl, alkoxy, an optionally substituted heterocyclic group having a nitrogen atom bonding to the naphthopyran ring as a heteroatom or a condensed heterocyclic group obtained by condensing the above heterocyclic group and an aromatic hydrocarbon ring or an aromatic heterocycle and (a) is an integer of 0-3.
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