Indolino-spiro-oxazine photochromic compounds having a five-membered ring, process for their preparation and photochromic compositions and materials containing them.

0001The present invention relates to new photochromic compounds of the indolino-spiro-oxazine type, their process for obtaining, as well as compositions and articles with photochromic properties containing at least one of said photochromic compounds.

0002Photochromism is a well-known reversible phenomenon, illustrated for example by a compound which changes color when it is exposed to light radiation, some of which belong to the UV field, in particular solar radiation, and which returns to its initial color when the light exposure is interrupted.

0003Such compounds are used for example in the manufacture of lenses for sun protection glasses or in other applications where the need arises to vary the transparency of an article as a function of the surrounding light intensity. They can be applied on a transparent support or incorporated in a transparent polymerized organic material in combination with a very wide variety of polymeric compositions.

0004A certain number of organic photochromic compounds comprising in their formula an indolino-spiro-oxazine group have already been proposed for such applications, in particular in the field of sun protection lenses.

0005Thus, American patents US 3,562,172 and 3,578,602 disclosed the photochromic effect of certain compounds belonging to the family of indolino-spironaphto-oxazines, while American patent US 4,215,010 describes indolinospironaphto-oxazines whose cycle Naphthalene is substituted by methoxy, ethoxy or a halogen atom. Analogous photochromic compounds comprising a pyridobenzene ring instead of the naphthalene ring of the above compounds are described in American patent US Pat. No. 4,720,547, as well as in international application WO 87/00524.

0006However, the compounds described in this prior art do not fully satisfy all of the qualities that one expects. If one places oneself more particularly within the framework of the application to sun protection lenses, the photochromic material obtained, whether it is from a solution of the photochromic compound or by incorporation thereof into an organic polymer, must have a certain number of properties concerning the photochromic effect, in addition to its natural transparency and its compatibility with the materials commonly used for such lenses.

0007In particular : - When it is irradiated in its photo-sensitivity range, the appearance of the coloration must appear rapidly, preferably in the order of a second, and its disappearance when the irradiation ceases must be just as rapid. - The material must be stable over time, both by itself and in its photochromism. Thus, the compound must be able to withstand within the material, a high number of coloring-discoloration cycles, throughout a period of use which may be several years. - The colorability must be good for reasonable levels of photochromic compound, and the absorption spectrum of the irradiated material must cover as much as possible the entire visible spectrum. - The photochromic effect must preferably be independent of the substrate containing the compound, and it must appear over a wide temperature range, both at variable ambient temperatures and when it is heated under irradiation. - The coloring taken by the material under irradiation must also respond to aesthetic concerns, by preserving a vision of the environment pleasant for the wearer of glasses or ophthalmic lenses made of such materials. From this point of view, the blue colors to which the abovementioned prior art compounds generally lead should be avoided, and green should be preferred.

0008In order to better meet these various requirements than the known compounds, the invention proposes new photochromic compounds, which are characterized in that they correspond to the formula of an indolino-spiro-oxazine comprising an indolinic part and a oxazine part, where the oxazine part comprises a five-membered unsaturated heterocycle.

0009According to secondary characteristics: - Said heterocycle comprises one or more heteroatoms chosen from nitrogen and sulfur, with a preference for those comprising at least one sulfur atom, or more particularly a sulfur atom and a nitrogen atom as in the thiazole nucleus. - Said heterocycle is ortho-condensed with a benzene nucleus of said oxazine part of the compound, the latter being of the benzo-oxazine type. - Said oxazine part is in particular, preferably, of the benzothiazolo-oxazine or indoleino-oxazine type. - Said heterocycle has a C = N-intracyclic imine bond.

0010The different rings of the indoline and oxazine parts of the molecule can carry various substituents which do not affect the overall photochromic properties of the compounds.

0011More particularly, the new compounds according to the invention advantageously have one of the following developed formulas:<chemistry id="chem0001" num="0001"><img file="EP0402228A2_D0001.tif" /></chemistry> in each of which: - <u style="single">not</u> varies from 0 to 4, - <u style="single">m</u> takes the values ​​1 or 2, - R₁ represents:<ul id="ul0001" list-style="none"><li>i) an alkyl group of 1 to 16 carbon atoms such as a methyl, ethyl, n-propyl, isopropyl, n-butyl group;</li><li>ii) an allyl, phenyl or arylalkyl group such as a benzyl or phenyl group mono or di-substituted by substituents of the alkyl or alkoxy type of 1 to 6 carbon atoms;</li><li>iii) an alicyclic group such as a cyclohexyl group, optionally substituted;</li><li>iv) an aliphatic hydrocarbon group comprising in its chain one or more heteroatoms such as O, N or S, in particular an acid, ester or alcohol function;</li></ul> - R₂ and R₃ may each and independently of one another represent a C₁₋₈ alkyl, phenyl, phenyl group mono or disubstituted by C₁₋₄ alkyl and / or C₁₋₅ alkoxy groups or may be combined to form a cyclic chain of 6 to 8 carbon atoms (including the spiranic carbon 3 of the indolinic heterocycle); - R₄ and R₅ can each and independently of one another represent:<ul id="ul0002" list-style="none"><li>i) a hydrogen atom, an amine function NR′R˝, where R ′ and R˝ each independently represent a hydrogen atom, an alkyl, cycloalkyl, phenyl group or a substituted derivative thereof; R ′ and R˝ may combine to form a cycloalkyl which may be substituted and contain one or more heteroatoms;</li><li>ii) a group R, OR, SR, COR or COOR in which R represents a hydrogen atom, an alkyl group of 1 to 6 carbon atoms or an aryl or heteroaryl group;</li><li>iii) a halogen atom, a C₁₋₄ monohaloalkyl group, the halogen being in particular Cl or Br, or a C₁₋₄ polyhaloalkyl group such as CF₃,;</li><li>iv) -NO₂, CN, SCN,</li></ul> each of the substituents R₄ possibly being present on any of the suitable carbon atoms of the indoline part of the photochromic compound, in position 4, 5, 6 and 7, when the other is a hydrogen atom, whereas when n = 2, it is preferable that the substituents are present in positions 4 and 5, 5 and 6, 4 and 6 or 6 and 7. - R₆ represents a hydrogen atom, or a C₁₋₈ alkyl or phenyl group, optionally substituted, or a functional group such as amino, carbonyl or halogen groups.

0012Preferably: - R₁ is a C₁₋₄ alkyl, phenyl or benzyl group; - R₂ and R₃ are chosen from C₁₋₅ alkyl groups such as methyl and ethyl and the phenyl group, or are combined to form a cyclohexyl group; each of the groups R₄ is chosen from the group consisting of hydrogen, C₁₋₂ alkyl, chlorine, fluorine, C₁₋₂ trihaloalkyle and C₁₋₅ alkoxy; - R₅ is a hydrogen atom, or a C₁₋₄ alkoxy group, or a tertiary amine; - R₆ is a hydrogen atom or an alkyl group of 1 to 4 carbon atoms.

0013Among the compounds according to the invention, the compounds in which: - the oxazine part is of the benzothiazolo-oxazine type: - R₁ is a C₁₋₄ alkyl group such as methyl or ethyl, isopropyl or n-butyl; - R₂ and R₃ each represent, independently of one another, a methyl or ethyl group; - R₄ is a hydrogen atom, a methyl, methoxy or chloro group; - R₅ is a hydrogen atom. - and R₆ is a methyl group.

0014The present invention also relates to a process for preparing the photochromic indolino-spiro-oxazine compounds represented by formulas (I) or (II).

0015In the second step, it exploits a general scheme for the synthesis of indolino-spiro-oxazines which is known in itself and which consists in carrying out the condensation of a Fischer base or indolin-2-alkylidene compound on a nitroso-hydroxy-hetero compound -aromatic. As a first step, the suitable nitroso-hydroxy-hetero-aromatic compound, such as that of the 7-nitroso-6-hydroxy-benzothiazole type for example, optionally substituted by one or more R₅ groups as defined for formulas I and II, may be prepared from an appropriate methoxy compound by hydrolysis to the corresponding hydroxy derivative, then nitrosation of the latter.

0016In their use for the preparation of photochromic compositions, the compounds according to the present invention can be dissolved in a suitable solvent such as toluene or ethanol in order to obtain a photochromic solution. These same photochromic compounds can also be dissolved in a polymer, a copolymer or a mixture of polymers in solution in a suitable organic solvent.

0017They thus enter into the composition of compositions according to the present invention, which can be applied or introduced into or onto a transparent organic polymer material to obtain a transparent photochromic article. Preferably, this material is a material of optical quality, more particularly a material suitable for the manufacture of ophthalmic lenses.

0018They can also enter into photochromic compositions which are also the subject of the present invention which can be used directly in the constitution of photochromic plastic films, of plates and of lenses such as lenses for sunglasses, viewfinders, camera optics and filters.

0019Examples of compositions suitable, in accordance with the invention, for the manufacture of transparent photochromic materials and articles, comprise one or more of the photochromic compounds of the present invention in combination with one or more of the following polymers: polymer of a polyolallylcarbonate monomer, polyacrylate, polyalkylacrylates such as polymethyl methacrylate (PMMA), cellulose acetate, cellulose triacetate, cellulose propiono and butyroacetate, polyvinyl acetate, polyvinyl alcohol, polyurethanes, polycarbonates, polyethyleneterephthalate, polystyrene, copolymers of styrene and methyl methacrylate, acrylonitrile, polyvinylbutyral.

0020The amount of photochromic compound (or composition containing this compound) applied or introduced onto or into the polymeric material is not of critical importance and it generally depends on the intensity of color desired under irradiation and on the method used to incorporate or apply the photochromic compound. The latter can be chosen from the numerous methods applicable to photochromic compounds of the prior art, including in particular the dissolution or dispersion of the compound in the basic composition of the material, or the production of a photochromic layer on the surface or at the surface. inside a transparent support material.

0021In general, the more photochromic compound is added, the more coloration under irradiation will be important. Such an amount can be described as a photochromic amount. Usually, the amount of photochromic compound incorporated into the optical material is from 0.01 to 20% by weight, and preferably from 0.05 to 10% by weight, relative to the total weight of optical material.

0022Photochromic effects are thus obtained, which result in the appearance of coloration under exposure to radiation belonging to the UV field, with return to the original color or transparency when the exposure to UV radiation is interrupted. color change can be repeated a very large number of times, as is required for sun protection glasses. In addition, the coloring persists throughout the time of exposure to solar radiation better than in the case of photochromic compounds of the prior art.

0023The invention will now be more fully illustrated by means of specific non-limiting examples of implementation.

EXAMPLE I

Step 1

0024<ul id="ul0003" list-style="none"><li>1) 1 g of 6-methoxy-2-methyl-benzothiazole (5.5.10⁻³ moles) is mixed with 0.9 g of 48% azeotropic hydrobromic acid (1.1 10⁻² moles). The reaction is carried out in a sealed tube at 125 ° C for 6 hours. After neutralization of the solution with 3N ammonia (pH = 7), the hydroxylated compound is extracted with chloroform. The yield is quantitative. Melting point: F = 147 ° C (C₈ H₇ NOS, M = 165).</li><li>2) A solution of 1.5 10⁻³ mole of sodium nitrite in 3 ml of water is added for one hour, with stirring, to a cooled solution (0-5 ° C) of 1.5 10⁻ ³ mole of 6-hydroxy-2-methyl benzothiazole obtained previously, 0.3 ml of concentrated hydrochloric acid and 3 ml of distilled water. Stirring is continued for 1 hour at low temperature. 6-hydroxy-7-nitroso-methyl-2-benzothiazole is thus obtained in the form of an orange precipitate which is washed with water and then dried. Yield 55%, F = 215 ° C (C₈H₆N₂O₂S, M = 194).</li></ul>

2nd step

0025The intermediate compound resulting from stage 1 is used to prepare a photochromic compound of formula I where R₄ is H and R₁, R₂, R₃ are all three methyl groups CH₃, as follows: 1.4 10⁻³ moles of Fischer base 1,3,3,3-trimethyl-2-methylene indoline are dissolved in 10 ml of n-heptane and 2 ml of anhydrous ethanol and heated to reflux. At constant temperature (around 76 ° C.), 1.4 × 10⁻³ moles of the heterocyclic nitroso hydroxy reagent from step I, suspended in 12 ml of anhydrous ethanol, are added slowly over 2 hours.

0026The reaction mixture is maintained at reflux for 45 min. As the reaction progresses slowly, the water is removed with ethanol by a Dean Stark device. About 30 ml of ethanol are then added to maintain a constant volume of solvent.

0027After passing the mixture through a chromatographic column of silica gel and removing the solvent by evaporation, the solid residue is recrystallized from an appropriate mixture of solvents, generally apolar, such as petroleum ether, diethyl ether, n-hexane or benzene. However, methanol or toluene can also be used.

0028The product obtained consists of indolino-spiro-oxazine of formula I, where R₆ is CH₃, or trimethylindolino-spiro-methyl-2 benzothiazolo-oxazine. The yield is of the order of 60% when the reaction solvent is a mixture of n-heptane and ethanol. Subsequent purification by recrystallization from a solvent medium brings the final yield to 40%.

EXAMPLE II

0029Under an inert nitrogen or argon atmosphere, 1.4 ml of a 1M solution of BBr₃ in dichloromethane is added to a stirred solution at 0 ° C of 1.2 10⁻³ moles of 5-methoxy-trimethyl -2.3.3 indoleinin in 1.5 ml of dichloromethane, to obtain 5-hydroxy-2,3,3-trimethylindolein.

0030The solution is stirred at room temperature and a precipitate appears. At the end of the reaction, hydrolysis is carried out with 0.1N HCl.

0031Nitrosation is then carried out in accordance with the procedure of 2) of step 1 of Example I, so as to obtain the 4-nitroso-5-hydroxy-2,3,3-trimethyl-indolenine.

0032By adopting the same procedure as in step 2 of Example I, and using the same Fischer indolin base, the preceding compound is subjected to the treatment of spiranic condensation.

0033This gives trimethylindolino-spiro-indolénino-oxazine, with a yield of the order of 40%

EXAMPLE III

0034By the procedure of Example I, the dimethyl isopropyl indolino-spiro-methyl-2-benzothiazolo-oxazine compound corresponding to formula I is prepared, in which R₂ and R₃, R mét are methyl groups, R is is an isopropyl group and R₄ and R₅ are hydrogen atoms.

EXAMPLE IV

0035By the procedure of Example I, the trimethyl-5-indhino-spiro-methyl-2-benzothiazolo-oxazine compound corresponding to formula I is prepared, where R₁, R₂, R₃ and R₆ are methyl groups, R₄ is a methoxy group in position 5 of the indoline ring and R₅ is a hydrogen atom.

EXAMPLE V

0036The photochromic compounds obtained in the previous examples are used in the preparation of varnishes based on polysiloxanes of the type of those described in French patent FR 82 0440, at a rate of 1% by weight. The varnish obtained is applied to ophthalmic lenses made of organic material, then cured for 2 h at 100 ° C. The thickness of the layers obtained is 2 microns. The percentage by weight of photochromic compound in the cured layer is of the order of 5%.

EXAMPLE VI

0037The various compounds of the preceding examples, in solution in a solvent, at the same concentration in the various samples, are subjected to staining tests under irradiation, in comparison with photochromic compounds of the prior art. For each sample, the wavelength corresponding to the maximum of its photostaining range (λmax) or the limits of the photostaining peak is determined.

0038The results obtained are recorded below: <tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col3" align="left">Compound</entry></row><row><entry namest="col1" nameend="col1" align="left"><u style="single">Prior art:</u></entry><entry namest="col2" nameend="col2" align="center"><u style="single">λ max (nm)</u></entry><entry namest="col3" nameend="col3" align="center"><u style="single">Color</u></entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Trimethylindolino-spiro-benzo-oxazine</entry><entry namest="col2" nameend="col2" align="right">590</entry><entry namest="col3" nameend="col3" align="left">Blue</entry></row><row><entry namest="col1" nameend="col1" align="left">N-methoxyethyl counterpart</entry><entry namest="col2" nameend="col2" align="right">606</entry><entry namest="col3" nameend="col3" align="left">Blue</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Homologated 6-methoxy N-methoxyethyl</entry><entry namest="col2" nameend="col2" align="right">603</entry><entry namest="col3" nameend="col3" align="left">Blue</entry></row></tbody></tgroup></table></tables><tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" align="left"><u style="single">Compounds of the invention:</u></entry><entry namest="col2" nameend="col2" align="center"><u style="single">Peak (nm)</u></entry><entry namest="col3" nameend="col3" align="left"><u style="single">Color</u></entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Example I</entry><entry namest="col2" nameend="col2" align="right">621</entry><entry namest="col3" nameend="col3" align="left">Blue green</entry></row><row><entry namest="col1" nameend="col1" align="left">Example III</entry><entry namest="col2" nameend="col2" align="right">626</entry><entry namest="col3" nameend="col3" align="left">Blue green</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Example IV</entry><entry namest="col2" nameend="col2" align="right">632</entry><entry namest="col3" nameend="col3" align="left">Blue green</entry></row></tbody></tgroup></table></tables>

0039We therefore observe, thanks to the invention, a shift in the green of the color appearing under irradiation, which is preferable for compounds intended for sun protection glasses or lenses.

0040Of course, the invention is in no way limited by the features which have been specified in the preceding examples or by the details of the particular modes of implementation chosen to illustrate the invention. All kinds of variations can be made to the operating conditions as well as to the nature and proportions of the constituents and reagents without departing from the scope of the invention.