Anti-aging photochromic dye and preparation method thereof

Abstract

The invention discloses an anti-aging photochromic dye and a preparation method thereof, and belongs to the technical field of fine chemical synthesis and optical functional materials. In the invention, the naphthyl ketone reacts with the succinate and the acetic anhydride to generate a hyperconjugated naphthol derivative, the naphthol derivative reacts with the hydroxyl-functionalized diaryl alkynol to generate the naphthopyran compound with the hyperconjugated structure, and the synthesis process is easy to operate. Moreover, the obtained naphthopyran compound with the hyperconjugate structure has relatively high color changing and fading speed and good aging resistance, and can be used in the fields of photochromic lenses, textiles, anti-counterfeiting, coatings and the like.

Description

Technical Field

[0001] The invention relates to an aging-resistant 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, fulgide-like compounds, 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 materials. When the ultraviolet radiation or visible light stimulation is removed, the restoration of the molecular structure and properties can be achieved. However, photochromic dyes can age. Long-term light exposure can cause the color-changing dyes to have negative effects such as discoloration and fading, and can reduce the rate of discoloration and fading, and eventually cause the coating to gradually lose its photochromic properties.

[0003] "Development of organic photochromic diarylethene dyes" (Zhu Shiqin, Li Mengqi, Zhu Weihong. Development of organic photochromic diarylethene dyes [J]. Nature Magazine, 2018, 40(2): 79-89.) discloses a type of diarylethene type photochromic dyes, which have excellent bistability and fatigue resistance. It can be seen that the aging resistance of photochromic dyes is an aspect that needs to be improved at present, and a new structure needs to be designed to make the photochromic dyes have aging resistance. Summary of the invention

[0004] Technical issues

[0005] Photochromic dyes can age. Long-term exposure to natural light can cause negative effects such as discoloration and fading, and reduce the rate of discoloration and fading, eventually causing the coating to gradually lose its photochromic properties. Therefore, it is necessary to develop new photochromic dye structures to solve the aging problem of photochromic dyes.

[0006] Technical content

[0007] In view of the above problems, the present invention designs the molecular structure of naphthopyran and synthesizes a hyperconjugated naphthopyran compound, which can achieve a rapid reversible photochromic effect from colorless to colored, and also has good aging resistance. The color-changing dye can be used in multiple anti-counterfeiting materials, color-changing glasses, color-changing textiles and clothing, color-changing inks and other fields.

[0008] The present invention provides an aging-resistant 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) or a benzene ring.

[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, R1, R2, R3, R4, R5, and R6 are hydrogen, and R7 and R8 are methyl.

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

[0015] Specifically, in Formula I, R5 and R6 are methoxy, R7 and R8 are ethyl, and R1, R2, R3, and R4 are hydrogen.

[0016] Specifically, in Formula I, R5 and R6 are methyl groups, R7 and R8 are benzene rings, and R1, R2, R3, and R4 are hydrogen.

[0017] The present invention also provides a method for preparing the naphthopyran compound, which comprises the following steps:

[0018]

[0019] (1) After dissolving succinate and compound A in an organic solvent, potassium tert-butoxide is added, and the mixture is reacted 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 B;

[0020]

[0021] (2) Compound B 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 recrystallized and separated to obtain Compound C;

[0022]

[0023] (3) reacting compound C with an alkaline solution, extracting, washing the extracted organic phase with water, separating the liquids, removing water from the organic phase obtained after separation, and spinning to dryness to obtain a crude product D;

[0024]

[0025] (4) Compounds D and E are dissolved in an organic solvent, an acidic catalyst is added, and the mixture is stirred at 30-100° C. for 1-12 hours. Water is then added to separate the layers, and the organic phase is separated by column chromatography to obtain compound F.

[0026]

[0027] (5) Compound F is dissolved in an organic solvent, an organic magnesium compound or an organic lithium compound is added at -20 to -10 degrees Celsius, and the mixture is stirred at 20 to 25 degrees Celsius for 10 to 20 hours to quench the reaction. After separation, the organic phase is washed with water, dried by rotation, recrystallized, and filtered to obtain a crude product G;

[0028]

[0029] (6) Compound G is dissolved in an organic solvent, an acidic catalyst is added, and the mixture is stirred at 80-120° C. for 5-12 h. The solvent is then removed and the mixture is separated by column chromatography to obtain Compound H.

[0030] Furthermore, in the above reaction formula, 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) or a benzene ring.

[0031] Furthermore, halogen is fluorine, chlorine or bromine.

[0032] Furthermore, in step (1), the molar ratio of succinate to compound A is 4:1 to 1.5:1.

[0033] Furthermore, in step (1), the molar ratio of potassium tert-butoxide to compound A is 5:1 to 1.5:1.

[0034] Furthermore, in step (1), the organic solvent is one or more of toluene, ethyl acetate, acetone, petroleum ether, acetonitrile, n-hexane, ether, chloroform, dichloromethane and dichloroethane.

[0035] Furthermore, with mL as the volume unit, the volume of the organic solvent used for the reaction and extraction in step (1) is 10 to 1000 times the molar amount of the compound; the molar amount of the compound is the sum of the molar amounts of succinate, compound A and potassium tert-butoxide.

[0036] Furthermore, with mL as the volume unit, the volume of water in step (1) is 10 to 1000 times the molar amount of the compound; the molar amount of the compound is the sum of the molar amounts of succinate, compound A and potassium tert-butoxide.

[0037] Furthermore, in step (2), the mass ratio of acetic anhydride to compound D is 15:1 to 5:1.

[0038] Furthermore, the base in step (2) includes one or more of NaHCO3, KHCO3, K2CO3, and Na2CO3.

[0039] Furthermore, the amount of saturated alkaline solution used in step (2) must ensure that acetic anhydride is completely decomposed.

[0040] Furthermore, in step (2), the organic solvent is one or more of toluene, ethyl acetate, acetone, petroleum ether, acetonitrile, n-hexane, ether, chloroform, dichloromethane and dichloroethane.

[0041] Furthermore, with mL as the volume unit, the volume of the organic solvent in step (2) is 10 to 1000 times the molar amount of the compound; the molar amount of the compound is the molar amount of compound B.

[0042] Furthermore, the alkali in the alkaline solution in step (3) includes one or more of NaHCO3, KHCO3, K2CO3, and Na2CO3.

[0043] Furthermore, the mass concentration of the alkali in the alkali solution in step (3) is 10 to 20 wt%.

[0044] Furthermore, in step (3), the ratio of the molar amount of compound C to the volume of the alkaline solution is 1 mmol:5-20 mL.

[0045] 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.

[0046] Furthermore, in step (4), the molar ratio of compound E to compound D is 1.5:1 to 1:1.

[0047] Furthermore, the amount of the acid catalyst used in step (4) is 2 to 10% of the molar amount of compound D.

[0048] Furthermore, in step (4), the organic solvent is one or more of toluene, ethyl acetate, acetone, petroleum ether, acetonitrile, n-hexane, ether, chloroform, dichloromethane and dichloroethane.

[0049] Furthermore, with mL as the volume unit, the volume of the organic solvent in step (4) is 10 to 1000 times the molar amount of the compound; the molar amount of the compound is the sum of the molar amounts of compound D, compound E and the acidic catalyst.

[0050] Furthermore, the organic magnesium compound in step (5) includes one or more of methylmagnesium bromide, methylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium chloride, propylmagnesium chloride, propylmagnesium bromide, phenylmagnesium bromide, phenylmagnesium chloride, and benzylmagnesium chloride; the organic lithium compound includes one or more of n-butyllithium, phenyllithium, methyllithium, and propyllithium.

[0051] Furthermore, in step (5), the molar ratio of compound F to the organomagnesium compound or the organolithium compound is 1:2 to 1:10.

[0052] Furthermore, the acid catalyst in step (6) includes one or more of methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dodecylsulfonic acid, pyridine p-toluenesulfonic acid, acidic alumina, heteropolyacid, and phosphoric acid.

[0053] Furthermore, in step (6), the amount of the acid catalyst used is 2 to 10% of the molar amount of compound G.

[0054] Furthermore, in step (6), the organic solvent is one or more of toluene, ethyl acetate, acetone, petroleum ether, acetonitrile, n-hexane, ether, chloroform, dichloromethane, and dichloroethane.

[0055] Furthermore, with mL as the volume unit, the volume of the organic solvent in step (6) is 10 to 1000 times the molar amount of the compound; the molar amount of the compound is the sum of the molar amounts of compound G and the acidic catalyst.

[0056] The hyperconjugated naphthopyran compound provided by the present invention is used in the fields of photochromic lenses, textiles, anti-counterfeiting and coatings.

[0057] Beneficial Effects

[0058] In the present invention, a naphthol aryl ketone is reacted with a succinate and acetic anhydride to generate a hyperconjugated naphthol derivative, and the naphthol derivative is reacted with the above-mentioned hydroxyl-functionalized diaryl alkynol to generate a hyperconjugated naphthopyran compound, and the synthesis process is easy to operate. In addition, the obtained hyperconjugated naphthopyran compound has a faster discoloration speed and good aging resistance, and the fading half-life can be controlled within 70 seconds and can remain unchanged after ultraviolet aging for 48 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a synthetic route for hyperconjugated naphthopyran compounds.

[0060] Figure 2 This is the UV absorption spectrum of compound H in Example 1. DETAILED DESCRIPTION

[0061] 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.

[0062] Source of raw materials

[0063] Unless otherwise specified, the compounds used in the examples are all common commercially available products and can be searched and purchased through online reagent platforms.

[0064] Example 1

[0065] Synthesis of compound H:

[0066]

[0067]

[0068] Step 1: Dimethyl succinate (20 mmol) and compound A (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 was completed by TLC spot plate detection, 30 mL of water was added to decompose the potassium tert-butoxide, and then the reaction solution was rotary evaporated to remove part of the solvent. 30 mL of water was added to the reaction solution after rotary evaporation. After standing and separating the liquids, the aqueous layer was extracted with a total of 60 mL of dichloromethane for 3 times. The extracted aqueous phase was acidified to pH = 2 with dilute hydrochloric acid, and then the acidified aqueous phase was extracted with a total of 120 mL of ethyl acetate for 3 times. The ethyl acetate was combined and spin-dried to obtain compound B.

[0069] Step 2: The compound B (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 50 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 recrystallized twice with a 3:1 petroleum ether and ethyl acetate solvent to obtain compound C.

[0070] Step 3: Compound C (10 mmol) was dissolved in 20 mL of methanol, 15 mL of 15% sodium carbonate solution was added, the reaction was stirred at 45 ° C for 5 h, the solvent was dried, 30 mL of ethyl acetate was added, and then washed twice with 50 mL of brine each time, and then allowed to stand for separation. The organic phase was dehydrated with anhydrous Na2SO4, filtered and separated, and the product was separated by column chromatography (the eluent was ethyl acetate and petroleum ether in a volume ratio of 1:10, and the product with a retention Rf value of 0.4) to obtain compound D.

[0071] Step 4: Compounds D (10 mmol) and E (11 mmol) were dissolved in 20 mL of dichloromethane, p-toluenesulfonic acid catalyst (0.5 mmol) was added, and the reaction was stirred at 45 ° C for 3 h. After the reaction was completed by TLC spot plate detection, a total of 100 mL of deionized water was added to wash three times, and the mixture was allowed to stand for separation. The organic phase was taken and the solvent was removed by vacuum rotary evaporation, and then the product was separated by column chromatography (the eluent was ethyl acetate and petroleum ether in a volume ratio of 1:8, and the product with an Rf value of 0.6 was retained) to obtain compound F.

[0072] Step 5: Compound F (10 mmol) was dissolved in 40 mL of anhydrous tetrahydrofuran, stirred at -10 degrees Celsius and 20 mL of 3 M methyl magnesium chloride tetrahydrofuran solution was added, stirred at 25 degrees Celsius for 12 hours, and after the reaction was completed by TLC spot plate detection, 40 mL of saturated ammonium chloride solution was added to quench, the organic phase was allowed to stand and washed three times with a total of 150 mL of saturated brine, the organic phase was separated and spin-dried, and then recrystallized twice with 3:1 n-hexane and ethyl acetate solvent, filtered, and dried to obtain compound G.

[0073] Step 6: Compound G (10 mmol) was dissolved in 50 mL of toluene, p-toluenesulfonic acid (0.5 mmol) was added, and the mixture was refluxed with stirring. After the reaction was completed by TLC spot plate detection, the solution was spin-dried, 50 mL of methanol was added for washing, the solid was filtered out, and the product was separated by column chromatography (the eluent was ethyl acetate and petroleum ether in a volume ratio of 1:6, and the product with an Rf value of 0.6 was retained) to obtain compound H.

[0074] The UV absorption spectrum of compound H is shown in Figure 2 .

[0075] Example 2

[0076] The synthesis steps of this example refer to Example 1, wherein the compound A in step 1 is replaced by a compound having the following structure in the same molar amount:

[0077]

[0078] Then, the compound E in step 4 is replaced by the same molar amount of a compound having the following structure:

[0079]

[0080] Finally, compound I was synthesized, and the chemical formula of compound I is shown below:

[0081]

[0082] Example 3

[0083] The synthesis steps of this example refer to Example 1, wherein the compound E in step 4 is replaced by a compound having the following structure in the same molar amount:

[0084]

[0085] Then, the methylmagnesium bromide in step 5 is replaced with propylmagnesium chloride in an equal molar amount, and finally compound J is synthesized. The chemical formula of compound J is shown below:

[0086]

[0087] Example 4

[0088] The synthesis steps of this example refer to Example 1, wherein the compound E in step 4 is replaced by a compound having the following structure in the same molar amount:

[0089]

[0090] Then, the methylmagnesium bromide in step 5 is replaced with phenylmagnesium chloride in an equal molar amount, and finally compound K is synthesized. The chemical formula of compound K is shown below:

[0091]

[0092] Comparative Example 1

[0093] Referring to the synthesis steps of Example 1, the compound A in step 1 is replaced by a diaryl ketone, and the structural formula of the diaryl ketone is as follows:

[0094]

[0095] Finally, a conventional naphthopyran compound M is synthesized, and the chemical formula of the compound M is shown below:

[0096]

[0097] Comparative Example 2

[0098] Referring to the synthesis steps of Example 1, compound A in step 1 is replaced by a ketone of the following structure:

[0099]

[0100] Finally, a conventional non-hyperconjugated naphthopyran compound N is synthesized, and the chemical formula of the compound N is shown below:

[0101]

[0102] The compounds finally obtained in Examples 1 to 4 and Comparative Examples 1 to 2 were respectively 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 the mold and thermally cured at 110°C for 2h. The thickness of the produced test lens was about 2 mm. The lens was irradiated with a 365nm ultraviolet light source, and the color change performance and fading half-life T of the lens sample were recorded. 1 / 2 , and the yellowing of the comparison samples after 48 hours of UV aging in the aging test box, the recorded data are as follows Table 1:

[0103] Table 1

[0104] sample 30s(Ta1%) <![CDATA[T 1 / 2 (S)]]> Yellowing Example 1 22.8 49 No significant changes Example 2 21.3 58 No significant changes Example 3 20.6 36 No significant changes Example 4 19.5 64 No significant changes Comparative Example 1 48.2 115 Slight yellowing Comparative Example 2 37.1 254 Slight yellowing

[0105] Ta represents the transmittance after 30 seconds of ultraviolet irradiation. The smaller the data, the deeper the color change. 1 / 2 It is the fading half-life. The smaller the value, the faster the fading speed.

[0106] 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. An aging-resistant 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, ethyl carboxylate or benzene ring.

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

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

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

5. The naphthopyran compound according to claim 1, characterized in that In formula I, R5 and R6 are methyl groups, R7 and R8 are benzene rings, and R1, R2, R3 and R4 are hydrogen.

6. The method for preparing a naphthopyran compound according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: (1) After dissolving succinate and compound A in an organic solvent, potassium tert-butoxide is added, and the mixture is reacted 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 B; (2) Compound B 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 recrystallized and separated to obtain Compound C; (3) reacting compound C with an alkaline solution, extracting, washing the extracted organic phase with water, separating the liquids, removing water from the organic phase obtained after separation, and spinning to dryness to obtain a crude product D; (4) Compounds D and E are dissolved in an organic solvent, an acidic catalyst is added, and the mixture is stirred at 30-100° C. for 1-12 hours. Water is then added to separate the layers, and the organic phase is separated by column chromatography to obtain compound F. (5) Compound F is dissolved in an organic solvent, an organic magnesium compound or an organic lithium compound is added at -20 to -10 degrees Celsius, and the mixture is stirred at 20 to 25 degrees Celsius for 10 to 20 hours to quench the reaction. After separation, the organic phase is washed with water, dried by rotation, recrystallized, and filtered to obtain a crude product G; (6) Compound G is dissolved in an organic solvent, an acidic catalyst is added, and the mixture is stirred at 80-120° C. for 5-12 h. The solvent is then removed and the mixture is separated by column chromatography to obtain Compound H.

7. The preparation method according to claim 6, characterized in that: The molar ratio of succinate to compound A in step (1) is 4:1 to 1.5:1; the molar ratio of potassium tert-butoxide to compound A in step (1) is 5:1 to 1.5:1; and the mass ratio of acetic anhydride to compound D in step (2) is 15:1 to 5:

1.

8. The preparation method according to claim 6, characterized in that: 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 aluminum oxide, heteropolyacid, and phosphoric acid; the molar ratio of compound E to compound D in step (4) is 1.5:1 to 1:1; the amount of the acid catalyst in step (4) is 2 to 10% of the molar amount of compound D.

9. The preparation method according to claim 6, characterized in that: In step (5), the organic magnesium compound includes one or more of methyl magnesium bromide, methyl magnesium chloride, ethyl magnesium bromide, ethyl magnesium chloride, propyl magnesium chloride, propyl magnesium bromide, phenyl magnesium bromide, phenyl magnesium chloride, and benzyl magnesium chloride; the organic lithium compound includes one or more of n-butyl lithium, phenyl lithium, methyl lithium, and propyl lithium; in step (5), the molar ratio of compound F to the organic magnesium compound or the organic lithium compound is 1:2 to 1:10; in step (6), the acid catalyst includes one or more of methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dodecylsulfonic acid, pyridine p-toluenesulfonic acid, acidic aluminum oxide, heteropolyacid, and phosphoric acid; and in step (6), the amount of the acid catalyst used is 2 to 10% of the molar amount of compound G.

10. Use of the naphthopyran compound according to any one of claims 1 to 5 in the fields of photochromic lenses, textiles, anti-counterfeiting or coatings.

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