Photochromic naphthopyrans

A photochromic 2H-naphtho-[1,2-b]pyran compound corresponding to formula (I)

• wherein
• X represents a saturated or unsaturated 2 to 4 member chain containing at least one carbon atom and a hetero moiety selected from the group consisting of O, S and NR4, wherein R4 is a linear or branched C1 to C6 alkyl group, a C5 to C7 cycloalkyl group, a phenyl group or a benzyl group, and said at least one carbon atom in X optionally is monosubstituted or disubstituted with at least one substituent selected from the group consisting of C1 to C6 alkyl, C1 to C6 alkoxy, phenyl, bromine, chlorine and fluorine;
• R1 is a substituent selected from the group A consisting of C1 to C6 alkyl, C1 to C6 alkoxy, C3 to C7 cycloalkyl optionally containing one hetero atom, phenyl, hydroxy, bromine, chlorine and fluorine;
• n is 0, 1 or 2;
• R2 and R3 are independently selected from the group G consisting of hydrogen, hydroxy, C1 to C6 alkyl, C1 to C6 alkoxy, C3 to C7 cycloalkyl, unsubstituted, monosubstituted and disubstituted phenyl, unsubstituted, monosubstituted and disubstituted naphthyl, and aromatic groups selected from the group C consisting of benzene, naphthalene, phenanthrene, pyridine, quinoline, furan, thiophene, pyrrol, benzofuran, benzothiophene, indol and carbazol, wherein the substituent or substituents of the phenyl or naphthyl group are selected from the group A;
• or
• R2 and R3 together with the spiro carbon atom form a 5- to 11-membered ring to which one or more aromatic or heteroaromatic ring systems selected from the group C may be annellated;
• or
• R2 and R3 together represent an oxygen atom to form a carbonyl group;
• B and B′ are independently selected from the groups a), b) and c), wherein
• a) consists of mono-, di- and trisubstituted aryl groups selected from the group consisting of phenyl and naphthyl;
• b) consists of unsubstituted, monosubstituted and disubstituted heteroaryl groups selected from the group consisting of pyridyl, furanyl, benzofuran-2-yl, benzofuran- 3-yl, thienyl, benzothien- 2-yl or benzothien- 3-yl;
• wherein the substituents of the aryl or heteroaryl groups in a) and b) are selected from the group consisting of hydroxy, amino, mono-(C1 to C6)-alkylamino, di-(C1 to C6)-alkylamino, mono- and diphenylamino in which the phenyl ring is unsubstituted, monosubstituted or disubstituted, piperidinyl, morpholinyl, carbazolyl, unsubstituted, monosubstituted and disubstituted pyrryl, C1 to C6 alkyl, C1 to C6 alkoxy, bromine, chlorine and fluorine, wherein the substitutents on the phenyl or pyrryl groups are selected from the group consisting of C1 to C6 alkyl, C1 to C6 alkoxy, bromine, chlorine and fluorine;
• c) consists of groups corresponding to the formulas (V) or (W)
• wherein
• Y and Z are independently selected from the group consisting of O, S, CH, CH2 and NR8, wherein R8 is selected from the group D consisting of C1 to C6 alkyl, C1 to C6 acyl and hydrogen;
• R5 is selected from the group A;
• and
• R6 and R7 are independently selected from the group consisting of hydrogen and C1 to C6 alkyl,
• with the proviso that when Y in formula (V) is NR8, Z is a carbon atom;
• or
• B and B′ together form an unsubstituted, monosubstituted or disubstituted fluorene-9-ylidene group wherein the substituents are selected from group A, or
• B and B′ form a saturated hydrocarbon group which is C3 to C12 spiro-monocyclic, C7 to C12 spiro-bicyclic or C7-C12 spiro-tricyclic.