PHOTOCHROMIC NAPHTHOPYRAN COMPOUNDS

摘要

A photochromic naphthopyran of formula (I) wherein R1 through R15, which may be the same or different, are independently selected from the group consisting of hydrogen, C1-C4 alkyl, C1-C4 alkoxy, halogen, C1-C4 alkylcarbonyloxy, benzoyloxy, C3-C6 cycloalkyl, phenyl, and NR16R17, wherein R16 and R17 are each C1-C4 alkyl or together with the N atom form a 5-12 membered monocyclic or polycyclic ring having, optionally, one or more further heteroatoms; R is hydrogen, alkyl or alkoxy; and >C(CnH2n+1)(CmH2m+1) is a tert-alkylene group, wherein n and m are integers from 1 to 5.