James Robinson Limited

John David Hepworth

Steven Michael Partington

Christopher David Gabbutt

Stephen Nigel Corns

David A Clarke

A photochromic grey coloring 2H-naphtho&lsqb;1,2-b&rsqb;pyran of formula (1) wherein R is selected from mono-, di- or poly-substituted aryl groups, mono-, di- or poly-substituted naphthyl groups and mono-, di- or poly-substituted heteroaryl groups, wherein at least one substituent is a nitrogen containing group, including amino, C -C and C -C alkylamino, C -C and C -C dialkylamino, C -C dialkenylamino, C -C or C -C di(polyalkenyl)amino, arylamino, diarylamino, C -C alkylarylamino, tetra (C -C linear or branched alkyl) guanidino and cyclic-amino groups and at least one of R and R , which may be the same or different, is selected from C -C N alkylamino C -C N-alkylamido, C -C N,N-dialkylamido, amido, nitro, amino, C -C alkylamino, C -C dialkylamino, C -C dialkenylamino, C -C di(polyalkenyl)amino, arylamino, diarylamino, C -C alkylarylamino, or cyclicamino groups. The compounds may be combined with a polymeric host material such as plastic or glass to make a sunglass lens, an ophthalmic lens or a window. The compounds may also be included in an ink or a fuel.

Grey coloring photochromic fused pyrans

A photochromic compound has the formula (I) wherein R,is selected from the group including substituted amino aryl moieties, substituted cyclic amino aryl moieties and substituted N-indolinoaryl or N-tetrahydroquinolino aryl groups, R,is selected from the group including linear or branched C,-C,alkyl, linear or branched C,-C,alkenyl or polyalkenyl, C,-C,alkynyl or polyalkynyl, aryl, heteroaryl, linear or branched C,-C,alkyl aryl, linear or branched C,-C,alkyl-cycloalkyl or -bicycloalkyl or -tricycloalkyl or substituted -cycloalkyl or -bicycloalkyl or -tricycloalkyl, linear or branched C,-C,haloalkyl or perhaloalkyl, linear or branched C,-C,alkoxyalkyl or peralkoxyalkyl, linear or branched C,-C,alkylthioalkyl or peralkylthioalkyl, linear or branched C,-C,amino alkyl or peraminoalkyl, C,-C,cycloalkyl or substituted cycloalkyl, C,-C,bicycloalkyl or substituted bicycloalkyl, C,-C,tricycloalkyl or substituted tricycloalkl or linear or branched C,-C,hydroxyalkyl or perhydroxyalkyl; R,and R,which may be the same or different are R,or R,and R,are conjoined to form a spiro linked C,-C,cyclic system or substituted cyclic system; and wherein R,and R,are each selected from R,or hydrogen, halogen, nitro, nitroso, amino, acetamido, C,-C,N-alkylamido, alkoxycarbonyl, nitrile, carboxy, hydroxy, aryloxy, C,-C,alkoxy, a heteroatom which is O or N or S or P which in turn can be bonded either singly or multiply to carbon, oxygen, sulphur or nitrogen, C,-C,alkoxy or alkylthio or aryl or aryloxy or multiples thereof.

Photochromic compounds

Red coloring hyperchromic compounds have the formula:

Red coloring hyperchromic 3H-naphtho&lsqb;2,1-B&rsqb;pyrans

Compositions comprising a naphtho &lsqb;1,2-b&rsqb;pyran of formula (I):

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Lancashire, United Kingdom

John David Hepworth