A novel photochromic dye and its preparation method

Abstract

The invention discloses a novel photochromic dye and a preparation method thereof, and belongs to the technical field of fine chemical synthesis and optical functional materials. The invention prepares a novel photochromic dye by reacting a diaryl ketone with (propynyloxy) trimethylsilane to generate a hydroxyl-functionalized diaryl alkynol, and reacting the diaryl ketone with succinate and acetic anhydride to generate a naphthol derivative, and reacting the naphthol derivative with the above-mentioned hydroxyl-functionalized diaryl alkynol to generate a cyclic lactone-modified naphthopyran compound. The photochromic dye has a fast discoloration speed, can be used in the fields of color-changing lenses, textiles, anti-counterfeiting, coatings, etc., and the preparation process is simple and easy to operate.

Description

Technical Field

[0001] The invention relates to a novel photochromic dye and a preparation method thereof, belonging to the technical field of fine chemical synthesis and optical functional materials. Background Art

[0002] Photochromic dyes are molecules whose structure changes from one state (or form) to another state after receiving radiation of a certain wavelength, and each state has a characteristic absorption spectrum. For example, many photochromic compounds change from an unactivated (e.g., whitish or substantially colorless) state to an activated (e.g., colored) state when exposed to ultraviolet radiation. Organic photochromic compounds, such as spiropyrans, naphthopyrans, spirooxazines, azobenzenes, diarylethenes, fulgides, etc., have been widely used in the fields of lenses, plastic products, coatings, textiles, inks, etc. These materials can undergo molecular photoisomerization under ultraviolet light irradiation, accompanied by changes in the absorption and emission properties of the material. When the ultraviolet radiation or visible light stimulation is removed, the restoration of the molecular structure and properties can be achieved.

[0003] At present, the field of photochromic materials has achieved remarkable development, but the number of reversible color-changing dyes that have been developed is still very limited, accounting for only the tip of the iceberg of the theoretical number, and there is still a lot of room for development. In addition, the existing photochromic molecules still have shortcomings such as complex preparation process and slow light response speed, so the material properties and preparation methods of photochromic molecules need to be further optimized and improved. Summary of the invention

[0004] Technical issues

[0005] The molecular structure of naphthopyran is the key factor that determines its color and discoloration performance. Although hundreds of naphthopyran compounds have been developed, these structures are only the tip of the iceberg of the theoretical number. There is still a lot of room for design of the molecular structure of naphthopyran, and more photochromic dyes with rich colors and good discoloration performance can be developed.

[0006] Technical content

[0007] In view of the above problems, the present invention synthesizes a cyclic lactone-modified naphthopyran compound by designing the molecular structure of naphthopyran and improving the synthesis process, which can achieve a rapid reversible photochromic effect from colorless to colored. The color-changing dye can be used in multiple anti-counterfeiting materials, color-changing glasses, color-changing clothing and other fields.

[0008] The present invention provides a cyclic lactone-modified naphthopyran compound, wherein the naphthopyran compound is shown in the following formula I:

[0009]

[0010] In formula I, R1, R2, R3, R4, R5, R6, R7 and R8 are independently selected from hydrogen, methyl, ethyl, methoxy, ethoxy, isopropoxy, trifluoromethyl, halogen, -N(CH3)2, -N(CH2CH3)2, methyl carboxylate (-COOMe) ethyl carboxylate (-COOEt), piperidinyl or polyether.

[0011] Furthermore, halogen is fluorine, chlorine or bromine.

[0012] Furthermore, R1, R2, R3, R4, R5, R6, R7 and R8 may be the same, partially the same or all different.

[0013] Specifically, in Formula I, R2, R4, R5 and R6 are methoxy groups, and R1, R3, R7 and R8 are hydrogen atoms.

[0014] Specifically, in Formula I, R2 and R4 are methoxy groups, and R1, R3, R5, R6, R7 and R8 are hydrogen atoms.

[0015] Specifically, in Formula I, R2 is piperidinyl, R5 and R8 are trifluoromethyl, and R1, R3, R6 and R7 are hydrogen.

[0016] The present invention also provides a method for preparing the naphthopyran compound, which comprises the following steps:

[0017]

[0018] (1) After (propynyloxy)trimethylsilane is dissolved in an organic solvent, n-BuLi is added at a temperature of -80 to -60°C with stirring, and then compound A is added, and then the temperature is raised to 20 to 30°C and stirred for reaction for 10 to 24 hours, and then an organic solvent and water are added, and then NH4Cl is added, and then the organic phase is separated, and the organic phase is filtered, concentrated, and separated by column chromatography to obtain compound B;

[0019]

[0020] (2) After dissolving the succinate and compound C in an organic solvent, potassium tert-butoxide is added, and the reaction is carried out at 70-110° C. for 12-30 hours. After the reaction is completed, water is added, and the mixture is allowed to stand for stratification. The aqueous layer is extracted with an organic solvent, and the pH of the aqueous phase obtained after the extraction is adjusted to 2-3. The acidified aqueous phase is then extracted with an organic solvent, and the organic phase obtained after the extraction is then dried to obtain compound D;

[0021] (3) Compound D is reacted with acetic anhydride at 90-120° C., and after the reaction is completed, a saturated alkaline solution is added, followed by extraction with an organic solvent, and the organic phase after extraction is dehydrated, filtered, and spin-dried to obtain a crude product, and the crude product is separated by column chromatography to obtain Compound E;

[0022]

[0023] (4) Compounds B and D are dissolved in an organic solvent, an acidic catalyst is added, and the mixture is stirred at 30-100° C. for 1-12 h. Water is then added to separate the layers, and the oil phase solution is separated by column chromatography to obtain compound F.

[0024] Furthermore, in step (1), the molar ratio of (propynyloxy)trimethylsilane to compound A is 2:1 to 1:1.

[0025] Furthermore, in step (1), the molar ratio of n-BuLi to (propynyloxy)trimethylsilane is 2:1 to 1:1.

[0026] Furthermore, the organic solvent in step (1) includes one or more of ethyl acetate, cyclohexane, chloroform, dichloromethane, tetrahydrofuran, and toluene.

[0027] Furthermore, in step (1), the volume of the organic solvent before the reaction is 5 to 20 times the volume of the reactants; the reactants are (propynyloxy)trimethylsilane, n-BuLi and compound A.

[0028] Furthermore, in step (1), the volume of the organic solvent and water after the reaction is 5 to 10 times the volume of the reactants respectively; the reactants are (propynyloxy)trimethylsilane, n-BuLi and compound A.

[0029] Furthermore, the amount of NH4Cl used in step (1) is 1 to 2 times the molar amount of n-BuLi.

[0030] Furthermore, in step (2), the succinate ester is dimethyl succinate or diethyl succinate.

[0031] Furthermore, in step (2), the molar ratio of succinate to compound C is 4:1 to 1.5:1.

[0032] Furthermore, in step (2), the molar ratio of potassium tert-butoxide to compound C is 5:1 to 1.5:1.

[0033] Furthermore, the organic solvent in step (2) includes one or more of ethyl acetate, cyclohexane, chloroform, dichloromethane, methyl tert-butyl ether, and toluene.

[0034] Furthermore, in step (2), the volume of the organic solvent before the reaction is 5 to 20 times the volume of the reactants; the reactants are succinate, compound C and potassium tert-butoxide.

[0035] Furthermore, the volume of the organic solvent used in the two extractions in step (2) is 10 to 50 times the volume of the reactants; the reactants are succinate, compound C and potassium tert-butoxide.

[0036] Furthermore, in step (3), the mass ratio of acetic anhydride to compound D is 15:1 to 3:1.

[0037] Furthermore, the base in step (3) includes one or more of NaHCO3, KHCO3, K2CO3, and Na2CO3.

[0038] Furthermore, the amount of saturated alkaline solution used in step (3) must ensure that acetic anhydride is completely decomposed.

[0039] Furthermore, the acid catalyst in step (4) includes one or more of methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dodecylsulfonic acid, pyridine p-toluenesulfonic acid, acidic alumina, heteropolyacid, and phosphoric acid.

[0040] Furthermore, in step (4), the molar ratio of compound B to compound E is 1.5:1 to 1:1.

[0041] Furthermore, in step (4), the amount of the acid catalyst used is 2 to 10% of the molar amount of compound B.

[0042] Furthermore, in step (4), the organic solvent is one of dichloromethane, 1,2-dichloroethane and toluene.

[0043] Furthermore, in step (4), the volume of the organic solvent is 5 to 20 times the volume of the reactants; the reactants are compound B and compound E.

[0044] Furthermore, the structural formula of compound A in step (1) is shown in Formula II below:

[0045]

[0046] In formula II, R1, R2, R3 and R4 are independently selected from hydrogen, methyl, ethyl, methoxy, ethoxy, isopropoxy, trifluoromethyl, halogen, -N(CH3)2, -N(CH2CH3)2, methyl carboxylate (-COOMe), ethyl carboxylate (-COOEt), piperidinyl or polyether.

[0047] Furthermore, the structural formula of compound C in step (2) is shown in Formula III below:

[0048]

[0049] In formula III, R5, R6, R7 and R8 are independently selected from hydrogen, methyl, ethyl, methoxy, ethoxy, isopropoxy, trifluoromethyl, halogen, -N(CH3)2, -N(CH2CH3)2, methyl carboxylate (-COOMe), ethyl carboxylate (-COOEt), piperidinyl or polyether.

[0050] The cyclic lactone-modified naphthopyran compound provided by the present invention is used in the fields of photochromic lenses, textiles, anti-counterfeiting and coatings.

[0051] Beneficial Effects

[0052] In the preparation process of the cyclic lactone-modified naphthopyran compound of the present invention, diaryl ketone and (propynyloxy) trimethylsilane are reacted to generate hydroxyl-functionalized diaryl alkynol, and at the same time, the diaryl ketone is reacted with succinate and acetic anhydride to generate naphthol derivatives, and the naphthol derivatives are reacted with the above-mentioned hydroxyl-functionalized diaryl alkynol to generate cyclic lactone-modified naphthopyran compound. The synthesis process is simple and easy to operate. In addition, the obtained cyclic lactone-modified naphthopyran compound has a faster discoloration speed and can be used in the fields of color-changing lenses, textiles, anti-counterfeiting, coatings, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The synthetic route of cyclic lactone-modified naphthopyran compounds.

[0054] Figure 2 is the compound F in Example 1 1 H NMR spectrum. DETAILED DESCRIPTION

[0055] The present invention is further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0056] Source of raw materials

[0057] Unless otherwise specified, the raw materials used in the examples and comparative examples are all common commercially available products.

[0058] Example 1

[0059] Synthesis of compound F:

[0060]

[0061] Step 1: After dissolving (propynyloxy)trimethylsilane (15mmol) in tetrahydrofuran (20mL), n-BuLi (20mmol) was added at -78°C and stirred. After 1h, compound A (10mmol) was added dropwise while maintaining -78°C. After the addition was complete, the temperature was raised to 25°C, and the reaction was stirred for 16h. Then 10mL of tetrahydrofuran and 10mL of water were added, and then NH4Cl (30mmol) was added. After stirring, the organic phase was separated by standing. The aqueous phase was extracted with a total of 30mL of ethyl acetate for 3 times. The extracted ethyl acetate and the separated organic phase were combined to obtain an organic mixed solution, which was then dried over anhydrous MgSO4. The dried organic mixed solution was filtered and concentrated under reduced pressure to obtain a crude product. The crude product was separated by column chromatography (using petroleum ether and ethyl acetate with a volume ratio of 10:1 as eluent) to obtain product B.

[0062]

[0063] Step 2: Diethyl succinate (20 mmol) and compound C (10 mmol) were dissolved in toluene (20 mL), potassium tert-butoxide (20 mmol) was added, and the mixture was reacted at 100°C for 20 h. After the reaction, 10 mL of water was added to decompose the potassium tert-butoxide, and then the reaction solution was evaporated to remove part of the solvent. 1-5 mL of water was added to the reaction solution after rotary evaporation and then allowed to stand for separation. The aqueous layer after separation was extracted with a total of 30 mL of dichloromethane for 3 times, and the extracted aqueous phase was acidified with dilute hydrochloric acid to pH = 2, and then the acidified aqueous phase was extracted with a total of 30 mL of ethyl acetate for 3 times, the ethyl acetate was combined, and the compound D was obtained by spin drying.

[0064] Step 3: The compound D (2 g) obtained above was mixed with acetic anhydride (20 mL) for reaction at 110°C, and the reaction was detected by TLC. After the reaction was completed, a saturated sodium bicarbonate solution was added to decompose the acetic anhydride, and then the reaction solution was extracted 3 times with a total of 30 mL of ethyl acetate, and then the organic phases were combined, washed 3 times with saturated brine, and then dried over anhydrous Na2SO4, filtered and dried to obtain a crude product, which was then separated by column chromatography (using petroleum ether and ethyl acetate in a volume ratio of 12:1 as eluent) to obtain compound E.

[0065]

[0066] Step 4: Dissolve compound B (10 mmol) and E (11 mmol) in 10 mL of dichloromethane, add p-toluenesulfonic acid catalyst (0.5 mmol), stir the reaction at 45 ° C for 3 h, then add 10 mL of deionized water and let stand to separate the liquid, take the organic phase and remove the solvent by vacuum rotary evaporation, and then separate the product by column chromatography (the eluent is ethyl acetate and petroleum ether in a volume ratio of 10:1) to obtain compound F.

[0067] Compound F 1 H NMR spectrum see Figure 2 .

[0068] Example 2

[0069] The synthesis steps of this embodiment refer to those of Example 1, wherein only the compound C in step 2 is replaced with the same molar amount of diphenyl ketone, and the chemical formula of the diphenyl ketone is as follows:

[0070]

[0071] Finally, compound G is synthesized, and the chemical formula of compound G is shown below:

[0072]

[0073] Example 3

[0074] The synthesis steps of this example refer to Example 1, wherein the compound A in step 1 is replaced by the same molar amount of compound H, and the chemical formula of the compound H is as follows:

[0075]

[0076] Then, the compound C in step (2) is replaced by the same molar amount of compound I, the chemical formula of which is as follows:

[0077] Finally, compound J was synthesized, and the chemical formula of compound J is shown below:

[0078]

[0079] Comparative Example 1

[0080] Synthesis of conventional naphthopyran compound K without cyclic lactone:

[0081]

[0082] The synthesis steps are similar to step (4) in Example 1, except that an alkynol without a hydroxymethyl group is used instead of compound B.

[0083] Comparative Example 2

[0084] Synthesis of Chemical M:

[0085]

[0086] The synthesis steps are similar to step (4) in Example 1, except that naphthol is used instead of compound E, and an alkynol without a hydroxymethyl group is used instead of compound B.

[0087] The above compound F, compound G, compound J and compound M were made into lenses, and the preparation process was as follows: 4 parts of ethoxybisphenol A dimethacrylate (EBPDMA, EO / phenol = 1.3), 1 part of poly (ethylene glycol) 400 dimethacrylate (PEGDMA) and 0.4wt% of AIBN (free radical initiator) relative to the total mass, and the photochromic compound content was 1.5% of the total mass. These mixtures were added to a mold and thermally cured at 110°C for 2h. The thickness of the produced test lens was about 2 mm.

[0088] When the lens is exposed to ultraviolet light, the initially colorless test lens sample becomes colored. After the irradiation stops, the lens will spontaneously return to the colorless state. The lens is irradiated with 365nm ultraviolet light for 30s and 2min in a ZF-20D dark box UV analyzer. The irradiated lens is placed in a blue-violet light tester to test the transmittance (Ta1 and Ta2) for 30s and 2min respectively. The unit is %, and then it is inserted into the formula (log (%Tb / %Ta), where Tb is the transmittance before color change 100% to obtain △OD, T 1 / 2 The fading half-life is the time required for the △OD of the sample to gradually decrease to half during the bleaching process after it has completely changed color.

[0089] The detection and comparison of fading performance are shown in Table 1 below.

[0090] Table 1

[0091] sample 30s(Ta1%) 2min(Ta2%) △OD <![CDATA[T 1 / 2 (S)]]> Example 1 20.8 19.7 0.718 45 Example 2 21.3 20.6 0.686 67 Example 3 20.2 18.4 0.735 53 Comparative Example 1 43.2 39.8 0.40 183 Comparative Example 2 60.5 59.7 0.224 524

[0092] Ta and Tb represent the transmittance after UV irradiation for 30 seconds and 2 minutes, respectively. The smaller the data, the deeper the color change depth. △ OD value exceeding 0.2 is up to standard, T 1 / 2 It is the fading half-life. The smaller the value, the faster the fading speed.

[0093] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A cyclic lactone-modified naphthopyran compound, characterized in that: The naphthopyran compound is shown in the following formula I: In formula I, R1, R2, R3, R4, R5, R6, R7 and R8 are independently selected from hydrogen, methyl, ethyl, methoxy, ethoxy, isopropoxy, trifluoromethyl, halogen, -N(CH3)2, -N(CH2CH3)2, methyl carboxylate (-COOMe) ethyl carboxylate (-COOEt), piperidinyl or polyether.

2. The naphthopyran compound according to claim 1, characterized in that In formula I, R2, R4, R5 and R6 are methoxy groups, and R1, R3, R7 and R8 are hydrogen atoms.

3. The naphthopyran compound according to claim 1, characterized in that In formula I, R2 and R4 are methoxy groups, and R1, R3, R5, R6, R7 and R8 are hydrogen atoms.

4. The naphthopyran compound according to claim 1, characterized in that In formula I, R2 is piperidinyl, R5 and R8 are trifluoromethyl, and R1, R3, R6 and R7 are hydrogen.

5. The method for preparing a naphthopyran compound according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: (1) After (propynyloxy)trimethylsilane is dissolved in an organic solvent, n-BuLi is added at a temperature of -80 to -60°C with stirring, and then compound A is added, and then the temperature is raised to 20 to 30°C and stirred for reaction for 10 to 24 hours, and then an organic solvent and water are added, and then NH4Cl is added, and then the organic phase is separated, and the organic phase is filtered, concentrated, and separated by column chromatography to obtain compound B; (2) After dissolving the succinate and compound C in an organic solvent, potassium tert-butoxide is added, and the reaction is carried out at 70-110° C. for 12-30 hours. After the reaction is completed, water is added, and the mixture is allowed to stand for stratification. The aqueous layer is extracted with an organic solvent, and the pH of the aqueous phase obtained after the extraction is adjusted to 2-3. The acidified aqueous phase is then extracted with an organic solvent, and the organic phase obtained after the extraction is then dried to obtain compound D; (3) Compound D is reacted with acetic anhydride at 90-120° C., and after the reaction is completed, a saturated alkaline solution is added, followed by extraction with an organic solvent, and the organic phase after extraction is dehydrated, filtered, and spin-dried to obtain a crude product, and the crude product is separated by column chromatography to obtain Compound E; (4) Compounds B and D are dissolved in an organic solvent, an acidic catalyst is added, and the mixture is stirred at 30-100° C. for 1-12 h. Water is then added to separate the layers, and the oil phase solution is separated by column chromatography to obtain compound F.

6. The preparation method according to claim 5, characterized in that: In step (1), the molar ratio of (propynyloxy)trimethylsilane to compound A is 2:1 to 1:1; the molar ratio of n-BuLi to (propynyloxy)trimethylsilane is 2:1 to 1:1; and the amount of NH4Cl used is 1 to 2 times the molar amount of n-BuLi.

7. The preparation method according to claim 5, characterized in that: In step (2), the molar ratio of succinate to compound C is 4:1 to 1.5:1; the molar ratio of potassium tert-butoxide to compound C is 5:1 to 1.5:

1.

8. The preparation method according to claim 5, characterized in that: In step (3), the mass ratio of acetic anhydride to compound D is 1.5:1 to 0.8:1; the base includes one or more of NaHCO3, KHCO3, K2CO3, and Na2CO3.

9. The preparation method according to claim 5, characterized in that: In step (4), the acid catalyst includes one or more of methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dodecylsulfonic acid, pyridine p-toluenesulfonic acid, acidic alumina, heteropolyacid, and phosphoric acid; the molar ratio of compound B to compound E is 1.5:1 to 1:1; and the amount of the acid catalyst is 2 to 10% of the molar amount of compound B.

10. Use of the naphthopyran compound according to any one of claims 1 to 4 or the naphthopyran compound prepared by the preparation method according to any one of claims 5 to 9 in the fields of photochromic lenses, textiles, anti-counterfeiting and coatings.

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