Neutral coloring photochromic 2H-naphtho[1,2-b]...

Details Neutral coloring photochromic 2H-naphtho[1,2-b]... Neutral coloring photochromic 2H-naphtho[1,2-b]...

1999-11-01

2001-06-19

Tucker, Philip (Department: 1712)

Compositions

Light transmission modifying compositions

Displaying color change

C549S389000, C549S058000, C549S060000, C544S150000, C546S196000, C546S282700, C548S465000, C548S525000, C351S163000

Reexamination Certificate

active

06248264

ABSTRACT:

The present invention relates to certain new photochromic pyran derivatives and to their use.
Photochromism is a well-known physical phenomenon which is observed with certain classes of chemical compounds. A detailed discussion of this phenomenon can be found in “Photochromism: Molecules and Systems,” Studies in Organic Chemistry 40, Eds. H Dürr and H. Bouas-Laurent, Elsevier, 1990.
The 2H-naphtho[1,2-b]pyran system is known to be capable of exerting a photochromic effect as described, for example, U.S. Pat. No. 3,567,605 and U.S. Pat. No. 4,826,977. U.S. Pat. No. 3,567,605 provides an example of a 2H-naphtho[1,2-b]pyran which remains coloured at ambient temperatures for several hours, and U.S. Pat. No. 4,826,977 describes a series of yellow/orange colouring 2H-naphtho[1,2-b]pyrans containing a spiro-adamantane group at the 2-position, amongst other 2H-[1]benzopyran and isomeric naphthopyran systems.n The basic structural unit of the 2H-naphtho[1,2-b]pyran system, in this instance substituted at C-2 with a spiro-adamantane group, is illustrated below.
A range of purple/blue colouring 2(4-aminophenyl)-2-alkyl-2H-naphtho[1,2-b]pyrans have also been described in U.S. Pat. No. 4,818,096.
A series of photochromic 2H-naphtho[1,2-b]pyrans, amongst other 2H-[1]benzopyrans and isomeric naphthopyrans, bearing a cyclopropyl group as one of the substituents at the 2-position is described in article WO92/01959. It is also commented that the compound 2-cyclopropyl-2-p-methoxyphenyl-5-methyl-2H-naphthop[1,2-b]pyran and several other analogues are of particular current interest, but no reasons were presented either to substantiate such interest or on any significance of the 5-methyl group.
It is stated in U.S. Pat. No. 5,066,818 (1991) that “The compound, 2,2diphenyl-2H-naphtho[1,2-b]pyran, also colours on exposure to near ultraviolet light at room temperature but does not bleach in a reasonable period of time. Substitution of the phenyl substituents in the meta and para positions have little effect on the rate of bleaching of these compounds.”
The very high optical density of 2,2-diaryl-2H-naphtho[1,2-b]pyrans achieved under irradiation and their slow attendant fade (bleaching) on removal of the source of irradiation relative to the photochromic properties displayed by the isomeric 3,3-diaryl-3H-naphtho[2,1-b]pyrans has been recently noted by B. van Gemert et al. (
Mol. Cryst. Liq. Cryst
., 1994, 246, 67). The relatively slow attendant fade of the 2,2-diaryl-2H-naphtho[1,2-b]pyrans was rationalised by the absence of steric crowding in the ring opened (coloured) quinoidal/zwitterionic forms. Such steric crowding is thought to be present for the ring opened form of the 3,3-diaryl-3H-naphtho[2,1-b]pyrans and accounts for their relatively rapid fade.
Pilkington Brothers Limited have also commented on the fading of photochromic materials in Research Disclosure. Two structurally similar deep colouring photochromic 2,2-diaryl-2H-naphtho[1,2-b]pyrans, namely 2,2-bis(4-methoxyphenyl)-5,6-dimethyl-2H-naphtho[1,2-b ]pyran and 2-(4-methoxyphenyl)-2-(4-trifluoromethylphenyl)-5,6-dimethyl-2H-naphtho-[1,2-b]pyran are described, which exhibit markedly improved attendant fade compared with the non-methyl substituted analogues. These improved rates of fade are attributed to the combined presence of methyl groups at the 5- and 6-positions, which are said to exert steric pressures upon the ring opened (coloured) quinoidal/zwitterionic forms, thereby enhancing the ring closure to the uncoloured naphthopyran system. However, these fast fade materials described by Pilkington plc with substituents at both the 5- and 6-positions are difficult to make, requiring a long multi-stage process which renders them unattractive commercially. Thus the use of two substituents at the 5- and 6-positions to achieve rapid fade in these 2,2-diaryl compounds has the disadvantage of manufacture complexities.
Two recent U.S. Pat. Nos., 5,458,814 and 5,514,817 describe the synthesis of a range fast fading intense yellow to red/purple colouring 2,2-diaryl-2H-naphtho[1,2-b]pyrans and phenanthropyrans which either possess a 5-substituent or are 5,6-disubstituted.
We have investigated these known photochromic compounds and have found that, for intense colour generation, compounds having 2,2-diaryl substituents are preferred. Also the presence of a 5 substituent in these 2,2-diaryl-2H-naphtho[1,2-b]pyrans ensures rapid fading of the colour generated upon irradiation. Furthermore, we have found that brown and brown/red photochromic 2,2-diaryl-2H-naphtho[1,2-b]pyrans can be obtained when the said 2,2-diaryl-2H-naphtho[1,2-b]pyran is substituted in the 7- or 9-position with an amino function.
According to the present invention, there is provided a polymeric host material or a solution including a photochromic compound of the formula I
In graphic formula I above, R
1
and R
2
are each selected from unsubstituted, mono-, di- or polysubstituted aryl groups, phenyl and heteroaryl groups, preferably mono- or di-substituted phenyl wherein the or each aryl group is not a naphthyl group. When R
1
and/or R
2
is selected from heteroaryl groups, each may be thienyl, benzo[b]thienyl, furyl, benzo[b]furyl, pyrryl, indolyl, pyridyl, quinolyl, isoquinolyl, pyrimidyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl, imidazolyl or benzimidazolyl.
The substituents for the aryl, naphthyl and heteroaryl groups representing R
1
and R
2
are linear or branched C
1
-C
20
alkyl, C
1
-C
20
cycloalkyl, C
1
-C
20
bicycloalkyl, C
1
-C
20
polycycloalkyl, linear or branched C
1
-C
10
haloalkyl, linear or branched C
1
-C
10
perhaloalkyl, linear or branched C
1
-C
10
perhaloalkenyl, linear or branched C
1
-C
10
alkenyl, C
1
-C
10
alkynyl, linear or branched C
1
-C
10
alkoxy, linear or branched C
1
-C
10
alkylthio, linear or branched C
1
-C
10
alkoxy (linear or branched C
1
-C
10
alkyl), linear or branched C
1
-C
10
hydroxyalkyl, linear or branched C
1
-C
10
aminoalkyl, aryl, phenyl, heteroaryl, halogen, nitrile, nitro, amino, linear or branched C
1
-C
20
alkoxycarbonyl, hydroxyl, formyl, acetyl, amido, C
1
-C
5
alkyl amido, C
1
-C
5
dialkylamido, aroyl, benzoyl, alkyl C
1
-C
5
amino, dialkyl C
1
-C
5
amino, arylamino, diarylamino, aryl C
1
-C
5
alkylamino and cyclicamino groups arylsulfinyl, arylsulfanyl, arylsulfonyl, linear or branched C
1
-C
10
alkylsulfonyl, P(O)(O—C
1
-C
10
alkyl)
2
.
For example, the substituents for the aryl and heteroaryl groups representing R
1
and R
2
may be C
1
-C
5
alkyl, C
1
-C
5
haloalkyl, C
1
-C
5
alkoxy, C
1
-C
5
alkoxy(C
1
-C
5
)alkyl, amino-C
1
-C
5
alkyl, hydroxy-C
1
-C
5
alkyl, halogen, amino, alkyl C
1
-C
5
amino, dialkyl C
1
-C
5
amino and cyclic amino groups (for example, aziridino, pyrrolidino, piperidino, morpholino, thiomorpholino, indolino, piperazino, C
1
-C
5
N-alkylpiperazino N-arylpiperazino). Other heteroaryl groups of R
1
and R
2
may be triazolyl, benzotriazolyl, or tetrazolyl.
Phenyl, aryl and heteroaryl ring substituents may be located at the o-, m- or p-positions. Typically, each phenyl group contains less than 3 substituents.
R
3
and R
4
are each hydrogen, R
1
, R
2
or as defined for R
5
below.
R
5
may be selected from linear or branched C
1
-C
10
alkyl, C
1
-C
20
cycloalkyl, C
1
-C
20
bicycloalkyl, C
1
-C
20
polycycloalkyl, linear or branched C
1
-C
10
haloalkyl, linear or branched C
1
-C
10
perhaloalkyl, linear or branched C
1
-C
10
perhaloalkenyl, linear or branched C
1
-C
10
alkenyl, C
1
-C
10
alkynyl, linear or branched C
1
-C
10
alkoxy, linear or branched C
1
-C
10
alkylthio, linear or branched C
1
-C
10
alkoxy (linear or branched C
1
-C
10
alkyl), linear or branched C
1
-C
10
hydroxyalkyl, linear or branched C
1
-C
10
aminoalkyl, aryl, phenyl, heteroaryl, halogen, nitrile, nitro, amino, linear or branched C
1
-C
20
alk

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