Various classes of photochromic compound have been synthesized and suggested for use in applications in which a sunlight-induced reversible color change or darkening is desired. U. S. Patent 3,567,605 (Becker) describes a series of pyran derivatives, including certain benzopyrans and naphthopyrans. These compound are described as derivatives of chromene and are reporte to undergo a color change, e. g., from colorless to yellow-orange, on irradiation by ultraviolet light at temperatures below about-30°C. Irradiation of the compound with visible light or upon raising the temperature to above about 0°C is reporte to reverse the coloration to a colorless state.

U. S. Patent No. 5,458,814 describes photochromic 2,2-disubstituted-5,6-substituted-2H-naphtho [1, 2-blpyran compositions primarily for use in lenses and other plastic transparencies having an acceptable fade rate in addition to a high activated intensity and a high coloration rate. U. S.

Patent No. 5,466,398 discloses 3,3-disubstituted-8- substituted-3H-naphtho [2,1-b] pyran compositions for similar

uses having additional substituents at the number 7 or number 9 carbon atom of the naphthopyran and which exhibit an improved solar response and higher activating wavelength than unsubstituted naphthopyrans.

U. S. Patent No. 5,289,547 describes a method for authenticating articles wherein a photochromic compound is incorporated into ink which is printed or coated onto an article. The photochromic compound is dissolve in the ink in sufficient quantities to produce a visible display of a predetermined pattern or the like when the ink is illuminated by appropriate wavelengths of light.

The compound disclosed in each of these patents are not water soluble, thus preparations thereof require organic solvents. Many suitable organic solvents are hazardous materials requiring specialized handling and disposa procedures.

United Kingdom Patent Application GB 2209751A discloses a method of producing water soluble photochromic fulgides, fulgimides and adamantylidene spiropyrans by incorporating therein a sulphonic acid or chlorosulphonic acid group or acid salt. The photochromic compound are sulphonated by treatment with sulphur trioxide or a dioxan- sulfur trioxide to impart water solubility thereto.

The present invention relates to novel water soluble photochromic compound namely, certain 2H-naphtho [1,2- b] pyrans, 3H-naphtho [2, 1-b]pyrans and benzopyrans each having at least one alkylaminoalkylamino group thereon. In an acidic environment, the alkylaminoalkylamino groups form quaternary salts, thereby rendering the photochromic compound water soluble. These compound have certain substituents on the pyran ring at the position ortho to the oxygen atom. Certain substituents are also present on the 2H-naphtho [1,2-b] pyran compound at the number 5 and 6 carbon atoms of the naphtho portion of the naphthopyran, on the 3H-naphtho [2,1-b] pyran compound at the number 8 and 9 carbon atoms of the naphtho

portion of the naphthopyran and on the benzopyran compound at the 5 and 6 carbon atoms.

DETAILED DESCRIPTION OF THE INVENTION In recent years, photochromic plastic materials, particularly plastic materials for optical applications, have been the subject of considerable attention. In particular, photochromic ophthalmic plastic lenses have been investigated because of the weight avantage they offer, vis-à-vis, glass lenses. Moreover, photochromic transparencies for vehicles, such as cars and airplanes, have been of interest because of the potential safety features that such transparencies offer.

Photochromic compound are also useful in various non-ophthalmic articles such as inks, paints and coatings for security documents and decorative or fashion items. In particular, water soluble photochromic compound possess processing and handling features not present in conventional water insoluble photochromic compound.

In accordance with the present invention, it has been discovered that certain photochromic 2H-naphtho [1,2- b] pyrans, 3H-naphtho [2,1-b] pyrans and benzopyrans which are traditionally water insoluble may now be made water soluble by including thereon an alkylaminoalkylamino group. When acidifie, the alkylaminoalkylamino group (s) forms quaternary ammonium salts rendering the compound water soluble. These compound may be described as 2H-naphtho [1, 2-b]pyrans and 3H- naphtho [2,1-b] pyrans, each having certain substituents at the 2 position and the 3 position, respectively, of the pyran ring and an alkylaminoalkylamino group on the naphtho portion of the naphthopyran ring. The 2H-naphtho [1, 2-b]pyrans and the 3H-naphtho [2, 1-b]pyrans also have certain other substituents at the 5 position and the 9 position, respectively, on the naphtho portion of the naphthopyran ring. The compound of the present invention also include benzopyrans having the same certain substituents at the 2 position of the pyran ring, certain other substituents at the 5 carbon atom and an

alkylaminoalkylamino group at the 6 carbon atom of the benzopyran ring. The aforedescribed naphthopyrans and benzopyrans may be represented by the following graphic formulae I, II and III in which the numbers 1 through 10 in graphic formulae I and II identify the ring atoms of the naphthopyrans and the numbers 1 through 8 in the graphic formula III identify the ring atoms of the benzopyran. In the definition of the substituents shown in graphic formulae I, II and III, like symbols have the same meaning unless stated otherwise.

In graphic formulae I, II and III, R1 is an alkylaminoalkylamino group represented by graphic formula IV: wherein R4 is Cl-C3 alkyl, phenyl (Cl-C3) alkyl, phenyl or R5, A is an anion, e. g., chloride, bromide, sulfate and phosphate.

In graphic formula IV, RS is a group represented by graphic formula V. wherein R6 and R7 are each Cl-C3 alkyl or Cl-C3 alkylamino (Cl-C3) alkylamino and m is the integer 2,3 or 4.

Preferably, R4 is methyl or 3-dimethylaminopropyl, and R6 and R7 are each methyl and m is 2,3 or 4; most preferably m is 3.

R2 in graphic formulae I, II and III is the group, -C (O) W or-CH20H, W being-OR8 or-N (Rg) R1o, wherein R8 is hydrogen, allyl, Cl-C6 alkyl, e. g., methyl, ethyl, propyl, butyl, pentyl, and hexyl, phenyl, mono (Cl-C6) alkyl substituted phenyl, mono (Cl-C6) alkoxy-substituted phenyl, phenyl (Cl-C3) alkyl, mono (Cl-C6) alkyl substituted phenyl (Cl-C3) alkyl, mono (Cl-C6) alkoxy substituted phenyl (Cl-C3) alkyl, Cl-C6 alkoxy (C2-C4) alkyl, or Cl-C6 haloalkyl; and Rg and Rlo may each be selected from the group consisting of hydrogen, Cl-C6 alkyl, C5-C7 cycloalkyl, phenyl and mono-or di-substituted phenyl. The phenyl substituents may be Cl-C6 alkyl and Cl-C6 alkoxy and the halo substituents may be chloro or fluoro.

More preferably, R2 is the group,-C (O) W, W being the groups-OR8 or-N (Rg) R10, wherein R8 is hydrogen, Cl-C4 alkyl, phenyl, mono (Cl-C4) alkyl substituted phenyl, mono (Cl-C4) alkoxy substituted phenyl, phenyl (Cl-C2) alkyl, mono (Cl-C4) alkyl substituted phenyl (Cl-C2) alkyl,

mono (Cl-C4) alkoxy substituted phenyl (Cl-C2) alkyl, mono (Cl-C4) alkoxy (C2-C3) alkyl, or Cl-C4 haloalkyl; and R9 and R10 may each be selected from the group consisting of hydrogen, Cl-C4 alkyl, C5-C7 cycloalkyl, phenyl and mono-or di-substituted phenyl. The phenyl substituents may be selected from Cl-C4 alkyl and Cl-C4 alkoxy, and the halo substituents may be chloro or fluoro. Most preferably, R2 is the group-C (O) W, W being the group-OR8, wherein R8 is a Cl-C3 alkyl.

Each R3 in graphic formula I is Cl-C6 alkyl, C3-C7 cycloalkyl, substituted or unsubstituted phenyl, or the group -OR11, wherein R1l is hydrogen or Cl-C6 alkyl, said phenyl substituents each being selected from Cl-C6 alkyl or Cl-C6 alkoxy, and n is the integer 0,1 or 2. Preferably, each R3 is Cl-C3 alkyl, C3-C5 cycloalkyl, substituted or unsubstituted phenyl or-OR11, wherein R1l is hydrogen or Cl-C3 alkyl, said phenyl substituents each being Cl-C3 alkyl or C1-C3 alkoxy and n is the integer 0 or 1.

B and B'in graphic formulae I, II and III may each be selected from the group consisting of: (i) the unsubstituted, mono-, di-and tri- substituted aryl groups, phenyl and naphthyl; (ii) the unsubstituted, mono-and di-substituted heteroaromatic groups pyridyl, furanyl, benzofuran-2-yl, benzofuran-3-yl, thienyl, benzothien-2-yl, benzothien-3-yl, dibenzofuranyl, dibenzothienyl, carbazolyl and fluorenyl, each of said aryl and heteroaromatic substituents in parts (i) and (ii) being selected from the group consisting of hydroxy, aryl, mono (CI-C6) alkoxyaryl, di (Cl-C6) alkoxyaryl, mono (Cl-C6) alkylaryl, di (Cl-C6) alkylaryl, bromoaryl, chloroaryl, fluoroaryl, C3-C7 cycloalkylaryl, C3-C7 cycloalkyl, C3-C7 cycloalkyloxy, C3-C7 cycloalkyloxy (Cl-C6) alkyl, C3-C7 cycloalkyloxy (Cl-C6) alkoxy, aryl (Cl-C6) alkyl, aryl (Cl-C6) alkoxy, aryloxy, aryloxy (Cl-c6) alkyl, aryloxy (Cl-C6) alkoxy, mono-and di (Cl-C6) alkylaryl (Cl-C6) alkyl, mono-and

di (Cl-C6) alkoxyaryl (Cl-C6) alkyl, mono-and di (Cl-C6) alkylaryl (Cl-C6) alkoxy, mono-and di (CI-C6) alkoxyaryl (Cl-C6) alkoxy, amino, mono (Cl-C6) alkylamino, di (Cl-C6) alkylamino, diarylamino, N- (Cl-C6) alkylpiperazino, N-arylpiperazino, aziridino, indolino, piperidino, arylpiperidino, morpholino, thiomorpholino, tetrahydroquinolino, tetrahydroisoquinolino, pyrryl, Cl-C6 alkyl, Cl-C6 bromoalkyl, Cl-C6 chloroalkyl, Cl-C6 fluoroalkyl, Cl-C6 alkoxy, mono (Cl-C6) alkoxy (Cl-C4) alkyl, acryloxy, methacryloxy, bromo, chloro and fluoro; (iii) the groups represented by the following graphic formulae: wherein E may be carbon or oxygen and D may be oxygen or substituted nitrogen, provided that when D is substituted nitrogen, E is carbon, said nitrogen substituents being selected from the group consisting of hydrogen, Cl-C6 alkyl and C2-C6 acyl; each R12 is Cl-C6 alkyl, Cl-C6 alkoxy, hydroxy, bromo, chloro or fluoro; R13 and R14 are each hydrogen or Cl-C6 alkyl; and p is the integer 0,1 or 2; (iv) Cl-C6 alkyl, Cl-C6 bromoalkyl, Cl-C6 chloroalkyl, Cl-C6 fluoroalkyl, Cl-C6 alkoxy (Cl-C4) alkyl, C3-C6 cycloalkyl, mono (Cl-C6) alkoxy (C3-C6) cycloalkyl, mono (Cl-C6) alkyl (C3-C6) cycloalkyl, bromo (C3-C6) cycloalkyl chloro (C3-C6) cycloalkyl and fluoro (C3-C6) cycloalkyl; and (v) the group represented by the following graphic formula:

wherein X in graphic formula VIc may be hydrogen or Cl-C4 alkyl and Y in graphic formula VIc may be selected from the unsubstituted, mono-, and di-substituted members of the group consisting of naphthyl, phenyl, furanyl and thienyl, each of said group substituents in this part (v) being Cl-C4 alkyl, Cl-C4 alkoxy, bromo, fluoro or chloro; or (vi) B and B' taken together form fluoren-9- ylidene, mono-or di-substituted fluoren-9-ylidene or form a member selected from the group consisting of saturated C3-C12 spiro-monocyclic hydrocarbon rings, e. g., cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexylidene, cycloheptylidene, cyclooctylidene, cyclononylidene, cyclodecylidene cycloundecylidene and cyclododecylidene; saturated C7-C12 spiro-bicyclic hydrocarbon rings, e. g., bicyclo [2.2.1] heptylidene, i. e., norbornylidene, 1,7,7- trimethyl bicyclo [2.2. 1[heptylidene, i. e., bornylidene, bicyclo [3.2. 1[octylidene, bicyclo [3.3. 1]nonan-9-ylidene and bicyclo [4.3. 2] undecane and saturated C7-C12 spiro-tricyclic hydrocarbon rings, e. g., tricyclo [2.2.1. 02,6]heptylidene and tricyclo [3.3.1. 13,7] decylidene, i. e., adamantylidene, and tricyclo [5.3.1. 12,6]dodecylidene, each of said fluoren-9- ylidene substituents being selected from the group consisting of C1-C4 alkyl, Cl-C4 alkoxy, bromo, fluoro and chloro.

More preferably, B and BI are each selected from the group consisting of: (i) phenyl, mono-substituted phenyl and di-substituted phenyl, preferably substituted in the meta and/or para positions; (ii) the unsubstituted, mono-and di- substituted heteroaromatic groups furanyl, benzofuran-2-yl, thienyl, benzothien-2-yl, dibenzofuran-2-yl and dibenzothien- 2-yl, each of said phenyl and heteroaromatic substituents in (i) and (ii) being selected from the group consisting of

hydroxy, aryl, aryloxy, aryl (Cl-C3) alkyl, amino, mono (CI-C3) alkylamino, di (Cl-C3) alkylamino, N- (Cl-C3) alkylpiperazino, indolino, piperidino, morpholino, pyrryl, Cl-C3 alkyl, Cl-C3 chloroalkyl, Cl-C3 fluoroalkyl, Cl-C3 alkoxy, mono (Cl-C3) alkoxy (Cl-C3) alkyl, fluoro and chloro; (iii) the groups represented by the graphic formulae VIa and VIb, wherein E is carbon and D is oxygen, R12 is Cl-C3 alkyl or Cl-C3 alkoxy, R13 and R14 are each hydrogen or Cl-C4 alkyl; and p is the integer 0 or 1; (iv) Cl-C4 alkyl; and (v) the group represented by the graphic formula VIc wherein X is hydrogen or methyl and Y is phenyl or mono-substituted phenyl, said phenyl substituent being selected from the group consisting of Cl-C3 alkyl, Cl-C3 alkoxy and fluoro; or (vi) B and Bu take together form fluoren-9-ylidene, mono-substituted fluoren-9-ylidene or a member selected from the group consisting of saturated C3-Cg spiro-monocyclic hydrocarbon rings, saturated C7-ClO spiro-bicyclic hydrocarbon rings and saturated C7-ClO spiro-tricyclic hydrocarbon rings, said fluoren-9-ylidene substituent being selected from the group consisting of Cl-C3 alkyl, Cl-C3 alkoxy, fluoro and chloro.

Most preferably, B and B, are each selected from the group consisting of (i) phenyl, mono-and di-substituted phenyl; (ii) the unsubstituted, mono-and di-substituted heteroaromatic groups furanyl, benzofuran-2-yl, thienyl and benzothien-2-yl, each of said phenyl and heteroaromatic substituents in (i) and (ii) being selected from the group consisting of hydroxy, Cl-C3 alkyl, Cl-C3 alkoxy, aryl, morpholino, fluoro and chloro; and (iii) the group represented by graphic formula VIa, wherein E is carbon and D is oxygen, R12 is Cl-C3 alkyl or Cl-C3 alkoxy, R13 and R14 are each hydrogen or Cl-C3 alkyl, and p is the integer 0 or 1; or (iv) B and Bu take together form fluoren-9-ylidene, adamantylidene, bornylidene, norbornylidene or bicyclo [3.3.1] nonan-9-ylidene.

Compound represented by graphic formula I may be prepared by the following steps. In Rection A, an alkyl

magnesium halide reagent is reacted with a secondary amine corresponding to the R1 group in graphic formulae I, II and III and represented by graphic formula VII in the presence of tetrahydrofuran (THF) to form the corresponding halomagnesium amide represented by graphic formula VIII wherein Z is a halide including bromide, chloride and iodide. rection A H N + alkyl Mg halide N MgZ THF R5 R5 VII VIII In Rection B, the halomagnesium amide represented by graphic formula VIII is reacted with the 2H-naphtho [1,2- b] pyran represented by graphic formula IX in the presence of THF and quenched with water to form compound represented by graphic formula Ia. In graphic formula IX, R1l is methyl.

The compound represented by graphic formula IX may be prepared by coupling a substituted naphtol with a propargyl alcool.

This procedure is described in U. S. Patent 5,458,814, column 5, line 10 to column 7, line 67. The propargyl alcohol may be prepared according to the methods disclosed in U. S. Patent 5,645,767, column 5, line 8 to column 6, line 30. The aforesaid patents are incorporated herein in toto by reference.

Rection B As shown in Rection C, when R3 is methoxycarbonyl, the compound represented by graphic formula Ia may be reduced by rection thereof with a ragent, preferably lithium aluminum hydride, in THF to form the compound represented by graphic formula Ib. The free base compound represented by graphic formulae Ia and Ib are acidifie to produce the corresponding quaternary ammonium salts which are water soluble.

Réaction C Examples of the free base of contemplated 2H- naphtho [1,2-b] pyrans within the scope of the invention are the following: (a) 2,2-bis (4-methoxyphenyl)-5-me'_oxycarbonyl-6- bis (3-dimethylaminopropyl) amino-2H-naphtho [1, 2-b]pyran ;

(b) 2,2-diphenyl-5-methoxycarbonyl-6-(3- dimethylaminopropyl) methylamino-2H-naphtho (1, 2-b] pyran; and (c) 2,2-diphenyl-5-methylol-6- (3- dimethylaminopropyl) methylamino-2H-naphtho [1,2-b] pyran.

Compound represented by graphic formula II may be prepared by first following Rection A to produce the halomagnesium amide represented by graphic formula VIII. In rection D, the 3H-naphtho [2, 1-b]pyran represented by graphic formula X is reacted with the halomagnesium amide represented by graphic formula VIII in the presence of THF and quenched with water to form compound represented by graphic formula IIa. In graphic formula X, R1l is methyl. The compound represented by graphic formula X may be prepared by coupling methyl-3,7-dihydroxy-2-naphthoate with propargyl alcool.

This procedure is disclosed in U. S. Patent 5,466,398, column 3, line 65 to column 9, line 28, incorporated herein in toto by reference. The propargyl alcohol may be prepared according to the methods disclosed in U. S. Patent 5,645,767. The compound represented by graphic formula IIa are acidifie to produce the corresponding quaternary ammonium salts which are water soluble.

Rection D

Examples of the free base form of contemplated [3H]-naphtho [2,1-b] pyrans within the scope of the invention are the following: (a) 3,3-bis (4-methoxyphenol)-8-bis (3-dimethyl aminopropyl) amino-3H-naphtho [2,1-blpyran; and (b) 3,3-diphenyl-8- (3-dimethylaminopropyl)- methylamino-3H-naphtho [2,1-b] pyran.

Compound represented by graphic formula III may be prepared by first following Rection A to produce the halomagnesium amide represented by graphic formula VIII. In Rection E, the dihydroxybenzoic acid represented by graphic formula XI is reacted with an alkyl halide or a benzylhalide, e. g., methyl iodide, ethyl chloride, benzyl bromide, etc., (R" halide) in the presence of ethyldiisopropyl amine or sodium bicarbonate in a suitable solvent such as anhydrous dimethylformamide (DMF) to form the corresponding dihydroxybenzoate represented by graphic formula XII.

Rection E OOH OOR" HO NaHC03 HO + Rllhalide 00 DMF OH OH XI XII In Rection F, propargyl alcohol represented by graphic formula XIII having the B and B'substituents defined above for graphic formulae I, II and III is coupled with the dihydroxybenzoate represented by graphic formula XII in the presence of p-toluene sulfonic acid (PTSA) in a suitable solvent such as toluene to produce benzopyrans represented by graphic formula XIV. The propargyl alcohol represented by graphic formula XIII may be prepared according to the method

described in U. S. Patent 5,645,767, column 5, line 8 to column 6, line 30. The benzopyrans represented by graphic formula XIV are alkylated, via, e. g., rection with methyl iodide in the presence of anhydrous potassium carbonate in a suitable solvent such as anhydrous acetone to form the alkoxy substituted benzopyran compound represented by graphic formula XV. Alkylating rections are further described in Organic Synthesis, Vol. 31, pages 90-93, John Wiley and Sons, Inc., New York, NY (1951).

Rection F COOR"OOR" HO H \ C B HO c b. PTSA /Tol e H OH Di xiv XII XIII Acetone CH3I K2C03 if CH30 < 0 O B' XV In Rection G, the benzopyran represented by graphic formula XV is reacted with the halomagnesium amide represented by graphic formula VIII in the presence of THF and quenched with water to form compound represer. n : ed by graphic formula IIIa. The alkoxycarbonyl group (-COOR") in graphic formula IIIa may be reduced by rection with a ragent, preferably, lithium aluminum hydrie, in THF to form the corresponding hydroxy compound. The compound represented by

graphic formula IIIa are acidifie to form the corresponding quaternary ammonium salts which are water soluble.

Rection G An example of the free base form of a contemplated benzopyran within the scope of the invention is 2,2-diphenyl- 5-methoxycarbonyl-6-bis (3-dimethylaminopropyl) amino-2H- benzopyran.

Aqueous solutions of the inventive photochromic compound may be used to incorporate the compound into an article. The water solubility of the naphthopyrans and benzopyrans of the present invention depends on the ratio of the number of hydrophilic moities to the number of hydrophobic moities thereon. The quaternary ammonium salt of the amino functionality identifie as the R1 substituent on these compound is hydrophilic. By water soluble it is meant that a mesurable amount of the photochromic compound of the present invention are soluble in water. The compound of the present invention having only two quaternary ammonium salt functionalities in the R1 group are soluble in water at about 1 gram per liter. It is contemplated that the inventive compound having more than two quaternary ammonium salt functionalities in the R1 group are more water soluble. Thus, the compound of the present invention are at least water soluble at one gram per liter. The present invention further

inclues the corresponding free bases of the quaternary ammonium salts represented by graphic formulae I, II and III.

The water soluble compound represented by graphic formulae I, II and III may be used in those applications in which organic photochromic substances may be employed, such as optical lenses, e. g., vision correcting ophthalmic lenses and plano lenses, face shields, goggles, visors, camera lenses, windows, automotive windshields, aircraft and automotive transparencies, e. g., T-roofs, sidelights and backlights, plastic films and sheets, textiles and coatings, e. g., coating compositions. Coating compositions are defined herein to include paints, i. e., a pigmente liquid or paste used for the decoration, protection and/or the identification of a substrate, and inks, i. e., a pigmente liquid or paste used for writing and printing on substrates. Substrats are materials to which the coating composition is applied, of any type such as, paper, glass, ceramics, wood, masonry, textiles, metals and organic polymeric materials. Coating compositions may be used to produce verification marks on security documents, e. g., documents such as banknotes, passport and drivers'licenses for which authentication or verification of authenticity may be desired. The water soluble photochromic compound of the present invention may also be used as tracers, e. g., in flow studies by injecting the inventive compound into a portion of an aqueous flow system, exposing the flow system to the appropriate UV light which will induce a color change in the inventive compound and monitoring their distribution in the flow system.

The 2H-naphtho- [1, 2-b] pyrans represented by graphic formula I exhibit color changes from colorless to colors ranging from yellow to red/purple. The 3H-naphtho [2,1- b] pyrans represented by graphic formula II exhibit color changes from colorless to colors ranging from yellow to orange and red. The benzopyrans represented by graphic formula III

exhibit color changes from colorless to colors rangiiag from red to purple.

It is contemplated that the photochromic naphthopyrans and benzopyrans of the present invention may each be used alone in the acid salts form, in combination with the acid salts of other naphthopyrans and benzopyrans of the present invention, or as the corresponding free bases in combination with one or more other appropriate complementary organic photochromic materials, i. e., organic photochromic compound having at least one activated absorption maxima within the range of between about 400 and 700 nanometers (or substances containing the same) and which color when activated to an appropriate hue. The photochromic compound of the present invention may be associated with, incorporated in, e. g., dissolve or disperse in, a polymeric organic host material used to prepare photochromic articles.

Other than where otherwise indicated, all numbers expressing wavelengths, quantities of ingredients or rection conditions used herein are to be understood as modifie in all instances by the term"about".

Examples of complementary organic photochromic compound include indenonaphthopyrans, chromenes and oxazines, naphthopyrans, substituted 2H-phenanthro (4,3-b] pyran and 3H- phenanthro [1, 2-b]pyran compound, other benzopyran compound having substituents at the 2-position of the pyran ring and mixtures of such photochromic compound. Many of such photochromic compound are described in the open literature, e. g., U. S. Patents 3,562,172; 3,567,605; 3,578,602; 4,215,010; 4,342,668; 4,816,584; 4,818,096; 4,626,977; 4,880,667; 4,931,219; 5,066,818; 5,238,981; 5,274,132; 5,384,077; 5,405,958; 5,429,774; 5,458,814,5,466,398; 5,514,817; 5,552,090; 5,552,091; 5,565,147; 5,573,712; 5,578,252; WO 96 14596 and Japanese Patent Publication 62/195383.

Spiro (indoline) pyrans are also described in the text, Techniques in Chemistry, Volume III,"Photochromism", Chapter

3, Glenn H. Brown, Editor, John Wiley and Sons, Inc., New York, 1971.

The disclosures relating to such photochromic compound in the aforedescribed patents are incorporated herein, in toto, by reference. The photochromic articles of the present invention may contain one photochromic compound or a mixture of photochromic compound, as desired.

Each of the photochromic substances described herein may be used in amounts (or in a ratio) such that an organic host material to which the photochromic compound or mixture of compound is applied or in which they are incorporated exhibits a desired resultant color, e. g., a substantially neutral color when activated with unfiltered sunlight, i. e., as near a neutral color as possible given the colors of the activated photochromic compound. Neutral gray and neutral brown colors are preferred.

A neutral gray color exhibits a spectrum that has relatively equal absorption in the visible range between 400 and 700 nanometers. A neutral brown color exhibits a spectrum in which the absorption in the 400-550 nanometer range is moderately larger than in the 550-700 nanometer range. An alternative way of describing color is in terme of its chromaticity coordinates, which describe the qualities of a color in addition to its luminance factor, i. e., its chromaticity. In the CIE system, the chromaticity coordinates are obtained by taking the ratios of the tristimulus values to their sum, e. g., x=X/ (X+Y+Z) and y=Y/ (X+Y+Z). Color as described in the CIE system can be plotted on a chromaticity diagram, usually a plot of the chromaticity coordinates x and y. See pages 47-52 of principales of Color Technology, by F. W. Billmeyer, Jr., and Max Saltzman, Second Edition, John Wiley and Sons, N. Y. (1981). As used herein, a near neutral color is one in which the chromaticity coordinate values of

"x"and"y"for the color are within the following ranges (D65 illuminant): x = 0.260 to 0.400, y = 0.280 to 0.400 following activation to 40 percent luminous transmission by exposure to solar radiation (Air Mass 1 or 2).

The amount of the photochromic naphthopyrans and/or benozpyrans to be applied to or incorporated into a carrier or host material is not critical provided that a sufficient amount is used to produce a photochromic effect discernible to the naked eye upon activation. Generally such amount can be described as a photochromic amount. The particular amount used depends often upon the intensity of color desired upon irradiation thereof and upon the method used to incorporate or apply the photochromic compound. Typically, the more photochromic compound applied or incorporated, the greater is the color intensity up to a certain limit.

The relative amounts of the aforesaid photochromic compound used will vary and depend in part upon the relative intensities of the color of the activated species of such compound, and the ultimate color desired. Generally, the amount of total photochromic compound incorporated into or applied to a photochromic optical host material may range from about 0.05 to about 1.0, e. g., from 0.1 to about 0.45, milligrams per square centimeter of volume or surface to which the photochromic compound is incorporated or applied.

The photochromic naphthopyrans and benzopyrans of the present invention may be associated with, applied to or incorporated within the host material by various methods described in the art. Such methods include dissolving or dispersing the photochromic compound in water or organic polymeric host material, e. g., casting it in place by adding the photochromic compound to the monomeric host material prior to polymerization; imbibition of the photochromic

compound into the host material by immersion of the host material in a hot solution of the photochromic compound or by thermal transfer; providing the photochromic compound as a separate layer between adjacent layers of the host material, e. g., as a part of a polymeric film; and applying the photochromic compound as part of a coating placed on the surface of the host material. The term''imbibitionll or "imbibe"is intended to mean and include permeation of the photochromic compound alone into the host material, solvent assiste transfer of the photochromic compound into a porous polymer, vapor phase transfer, and other such transfer mechanisms.

Compatible (chemically and color-wise) tints, i. e., dyes, may be applied to the host material to achieve a more aesthetic result, for medical reasons, or for reasons of fashion. The particular dye selected will vary and depend on the aforesaid need and result to be achieved. In one embodiment, the dye may be selected to complement the color resulting from the activated photochromic compound, e. g., to achieve a more neutral color or absorb a particular wavelength of incident light. In another embodiment, the dye may be selected to provide a desired hue to the host material when the photochromic compound are in an unactivated state.

The host material will usually be transparent, but may be translucent or even opaque. The host material need only be pervious to that portion of the electromagnetic spectrum, which activates the photochromic substance, i. e., that wavelength of ultraviolet (W) light that produces the open or colored form of the substance and that portion of the visible spectrum that inclues the absorption maximum wavelength of the substance in its UV activated form, i. e., the open form. Preferably, the host color should not be such

that it masks the color of the activated form of the photochromic compound, i. e., so the change in color is readily apparent to the observer.

The photochromic compound of the present invention are soluble in water when acidifie to form quaternary salts.

Aqueous solutions of the quaternary salts of the photochromic compound may be used to disperse the photochromic compound into an organic polymeric host material or other materials such as textiles and ink or paint bases. Alternatively, the free base form of the photochromic compound may be dissolve in an organic solvent. The organic solvent may be selected from the group consisting of benzene, toluene, methyl ethyl ketone, acetone, ethanol, tetrahydrofurfuryl alcool, N-methyl pyrrolidinone, 2-methoxyethyl ether, xylene, cyclohexane, 3- methyl cyclohexanone, ethyl acetate, tetrahydrofuran, methanol, methyl propinate, ethylene glycol and mixtures thereof. Preferably, the organic solvent is selected from the group consisting of acetone, ethanol, tetrahydrofurfuryl alcool, 2-methoxyethyl ether, 3-methyl cyclohexanone, N- methyl pyrrolidinone and mixtures thereof. Preferably, the organic polymeric host material is a solid transparent or optically clear material, e. g., materials suitable for optical applications, such as plano and ophthalmic lenses, windows, automotive transparencies, e. g., windshields, aircraft transparencies, plastic sheeting, polymeric films, etc.

Examples of polymeric organic host materials are polymers prepared from individual monomers or mixtures of monomers selected from the following groups: (a) diacrylate or dimethacrylate compound represented by graphic formula XVI:

wherein R, S and R16 may be the same or different and are hydrogen or methyl, and V is methylene (CH2) and t is an integer of from 1 to 20; (b) diacrylate or dimethacrylate compounds represented by graphic formula XVII: wherein L is CH2CH (R16), or (CH2) v, wherein v is an integer selected from the group consiting of 1,3 and 4, and s is an integer of from 1 to 50; and (c) an acrylate or a methacrylate compound having an epoxy group represented by graphic formula XVIII: wherein R18 is hydrogen or methyl.

In graphic formulae XVI, XVII and XVIII, like letters used with respect to the definitions of different substituents have the same meaning.

Examples of diacrylate or dimethacrylate compound represented by graphic formulae XVI include butanediol di (meth) acrylate, hexanediol di (meth) acrylate and nonanediol di (meth) acrylate, and represented by graphic formula XVII include diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, etc., butanediol dimethacrylate and poly (oxyalkylene dimethacrylates), e. g., polyethylene glycol (600) dimethacrylate. Examples of acrylate or methacrylate compound represented by graphic formula XVIII include glycidyl acrylate and glycidyl methacrylate.

Further examples of polymeric organic host materials which may be used with the photochromic compound described herein include: polymers, i. e., homopolymers and copolymers, of the monomers and mixtures of monomers represented by graphic formulae XVI, XVII and XVIII, bis (allyl carbonate) monomers, diisopropenyl benzene monomers, ethoxylated bisphenol A dimethacrylate monomers, ethylene glycol bismethacrylate monomers, poly (ethylene glycol) bismethacrylate monomers, ethoxylated phenol bismethacrylate monomers, alkoxylated polyhydric alcohol polyacrylate monomers, such as ethoxylated trimethylol propane triacrylate monomers, urethane acrylate monomers, such as those described in U. S. Patent 5,373,033, and vinylbenzene monomers, such as those described in U. S. Patent 5,475,074 and styrene; polymers, i. e., homopolymers and copolymers, of polyfunctional, e. g., mono-, di-or multi-functional, acrylate and/or methacrylate monomers, poly (C1-C12 alkyl methacrylates), such as poly (methyl methacrylate), poly (alkoxylated phenol methacrylates), cellulose acetate,

cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, poly (vinyl acetate), poly (vinyl alcool), poly (vinyl chloride), poly (vinylidene chloride), polyurethanes, thermoplastic polycarbonates, polyesters, poly (ethylene terephthalate), polystyrene, poly (alpha methylstyrene), copoly (styrene-methyl methacrylate), copoly (styrene-acrylonitrile), polyvinylbutyral and polymers, i. e., homopolymers and copolymers, of diallylidene pentaerythritol, particularly copolymers with polyol (allyl carbonate) monomers, e. g., diethylene glycol bis (allyl carbonate), and acrylate monomers, e. g., ethyl acrylate, butyl acrylate.

Transparent copolymers and blends of transparent polymers are also suitable as host materials. Preferably, the host material is an optically clear polymerized organic material prepared from a thermoplastic polycarbonate resin, such as the carbonate-linked resin derived from bisphenol A and phosgene, which is sold under the trademark, LEXAN; a polyester, such as the material sold under the trademark, MYLAR; a poly (methyl methacrylate), such as the material sold under the trademark, PLEXIGLAS; polymerizates of a polyol (allyl carbonate) monomer, especially diethylene glycol bis (allyl carbonate), which monomer is sold under the trademark CR-39, and polymerizates of copolymers of a polyol (allyl carbonate), e. g., diethylene glycol bis (allyl carbonate), with other copolymerizable monomeric materials, such as copolymers with vinyl acetate, e. g., copolymers of from 80-90 percent diethylene glycol bis (allyl carbonate) and 10-20 percent vinyl acetate, particularly 80-85 percent of the bis (allyl carbonate) and 15-20 percent vinyl acetate, and copolymers with a polyurethane having terminal diacrylate functionality, as described in U. S. Patents 4,360,653 and

4,994,208; and copolymers with aliphatic urethanes, the terminal portion of which contain al. lyl or acrylyl functional groups, as described in U. S. Patent 5,200,483; poly (vinyl acetate), polyvinylbutyral, polyurethane, polymers of members of the group consisting of diethylene glycol dimethacrylate monomers, diisopropenyl benzene monomers, ethoxylated bisphenol A dimethacrylate monomers, ethylene glycol bismethacrylate monomers, poly (ethylene glycol) bismethacrylate monomers, ethoxylated phenol bismethacrylate monomers and ethoxylated trimethylol propane triacrylate monomers; cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, polystyrene and copolymers of styrene with methyl methacrylate, vinyl acetate and acrylonitrile.

More particularly, contemplated is use of the photochromic naphthopyrans and benzopyrans of the present invention with optical organic resin monomers used to produce optically clear polymerizates, i. e., materials suitable for optical applications, such as for example plano and ophthalmic lenses, windows, and automotive transparencies. Such optically clear polymerizates may have a refractive index that may range from about 1.48 to about 1.75, e. g., from about 1.495 to about 1.66. Specifically contemplated are optical resins sold by PPG Industries, Inc. under the CR-designation, e. g., CR-307 and CR-407.

The water soluble photochromic compound of the present invention offer handling and processing avantages not achieved by water insoluble photochromic compound. In particular, the use of hazardous organic solvents as carriers for photochromic compound is avoided. As a final step in the preparation of optical lenses and other transparent polymeric articles, the surfaces thereof must be cleaned of excess

photochromic compound. Because the photochromic compound of the present invention are water soluble in an acidic environment, such surfaces may be cleaned with a dilute acid.

It is further contemplated that the photochromic naphthopyrans and benzopyrans of the present invention may be used in aqueous or organic based inks or paints. The inventive photochromic compound may be incorporated into different printing inks and paints for application on various articles including printed documents, printed textiles, and painted or coated articles for functional or decorative purposes. Hereafter, by the term ink it is meant all inks, paints and the like for application to another article or incorporation into another composition. The inventive photochromic compound should (a) provide a mesurable photochromic response when incorporated into an ink and exposed to a source of activating light, (b) be soluble within the ink and (c) be chemically compatible with the base ink composition.

Although the present invention has been described with respect to photochromic 2H-naphtho [1,2-b] pyrans, 3H- naphthof2,1-b] pyrans and benzopyrans, other related photochromic compound could be made water soluble via amination in a similar manner. Such other related photochromic compound include compound having an alkoxy group at a position ortho to an ester substituent suitable for coupling with a halomagnesium amide and subsequent acidification thereof to produce a water soluble amino- substituted photochromic compound.

The present invention is more particularly described in the following examples which are intended as illustrative only, since numerus modifications and variations therein will be apparent to those skilled in the art.

EXAMPLE 1 Step1 Bis (3-dimethylaminopropyl) amine (4 grams) was added to a rection flask containing 50 milliliters (mL) of anhydrous tetrahydrofuran (THF) and stirred at room temperature. Methyl magnesium bromide in a stoichiometric amount (7 mL of a 3 molar hexane solution) was added-and stirred for one hour. The rection mixture containing bromomagnesium bis (3-dimethylaminopropyl) amide was not purifie but used directly in the next step.

Step2 2,2-bis (4-methoxyphenyl)-5-methoxycarbonyl-6- methoxy-2H-naphtho [1,2-b] pyran (3 grams) was added to a flask containing anhydrous tetrahydrofuran (5mL). The naphthopyran solution was added to the rection mixture of Step 1 and stirred at room temperature for two hours. Water (100 mL) was slowly added and stirred for one half hour. The resulting mixture was extracted three times with diethyl ether (25 mL each). The three organic extracts were combine and washed with distille water. The resulting diethyl ether solution was extracted three times with a 10 weight percent hydrochloric acid solution (25 mL each). The three acid solutions were combine and neutralized with a 10 weight percent sodium hydroxide solution. The resulting neutral solution was extracted three times with diethyl ether (25 mL each). The three organic extracts were combine, washed with water and dried over anhydrous magnesium sulfate. The solvent was evaporated leaving 2 grams of an oily product. A nuclear magnetic resonance (NMR) spectrum showed the product to have a structure consistent with 2,2-bis (4-methoxyphenyl)-5- methoxycarbonyl-6-bis (3-dimethylaminopropyl) amino-2H- naphtho[1,2-b]pyran.

Step3 The 2,2-bis (4-methoxyphenyl)-5-methoxycarbonyl-6- bis (3-dimethylaminopropyl) amino-2H-naphtho [1,2-b] pyran prepared in Step 2 was added to a rection flask containing anhydrous diethyl ether. The solution was bubbled with dry hydrochloric acid gas until a white solid separated out. The solid was removed from the solution by filtration, washed with anhydrous diethyl ether, washed with hexane, dried and was determined to have a water solubility of 1 gram per liter.

Upon acidification and illumination with ultraviolet light, an aqueous solution of the product exhibited a red-purple color.

EXAMPLE 2 Stem 1 The procedure of Step 1 of Example 1 was followed except that N, N', N'-trimethyl-1,3-propanediamine was used in place of bis (3-dimethylaminopropyl) amine to produce a rection mixture containing bromomagnesium N, N', N'-trimethyl-1,3- propanediamide.

Step2 2,2-diphenyl-5-methoxycarbonyl-6-methoxy-2H- naphtho [1, 2-b]pyran (3 grams) was added to a flask containing anhydrous tetrahydrofuran (10 mL). The resulting naphthopyran solution was added to the rection mixture of Step 1 and stirred at room temperature for two hours. Water (100 mL) was added to the rection mixture and the resulting mixture was extracted three times with diethyl ether (25 mL each). The organic extracts were combine, washed with water, and dried over anhydrous magnesium sulfate. The solvent was evaporated leaving an oily product. The oily product was induced to crystallize from diethyl ether. The solid product was suction filtered, washed with hexane and air dried, leaving 2.5 grams of the recovered product. The recovered product had a melting point of 154-155°C. A nuclear magnetic resonance (NMR) spectrum showed the product to have a structure consistent

with 2,2-diphenyl-5-methoxycarbonyl-6- (3- dimethylaminopropyl) methylamino-2H-naphtho [1,2-b] pyran. Upon acidification and illumination with ultraviolet light, an aqueous solution of the product exhibited a red color.

EXAMPLE 3 The 2,2-diphenyl-5-methoxycarbonyl-6- (3- dimethylaminopropyl) methylamino-2H-naphtho [1,2-b] pyran (2 grams) prepared in Example 2, Step 2, was added to a rection flask containing anhydrous tetrahydrofuran (50 mL) and stirred at room temperature. Lithium aluminum hydride (1 gram) was added slowly to the flask and stirred for two hours. A 5 weight percent hydrochloric acid solution (100 mL) was added and stirred for one half hour. The aqueous layer was separated, washed with diethyl ether (25 mL), and neutralized with a 10 weight percent sodium hydroxide solution. The resulting neutral solution was extracted ten times with diethyl ether (20 mL each). The organic extracts were combine, washed with water, and dried over anhydrous magnesium sulfate. The solvent was evaporated leaving 1 gram of an oily product. A nuclear magnetic resonance (NMR) spectrum showed the product to have a structure consistent with 2,2-diphenyl-5-methylol-6- (3- dimethylaminopropyl) methylamino-2H-naphtho [1, 2-b]pyran. Upon acidification and illumination with ultraviolet light, an aqueous solution of the product exhibited a red color.

The present invention has been described with reference to specific details of particular embodiments thereof. It is not intended that such details be regarde as limitations upon the scope of the invention except insofar as to the extent that they are included in the accompanying claims.