Use of tetrahydronaphthiridine derivatives to manufacture products that improve hyperpigmentation

Abstract

The present invention provides the use of a compound represented by formula I, a pharmaceutically acceptable salt, hydrate, isomer, prodrug, or a mixture thereof, for manufacturing a product for improving pigmentation. This compound is very promising for the treatment of melasma. [Chemical 1] JPEG2025518798000031.jpg31169

Description

Detailed description of the invention

[0001] This invention claims priority to a prior application filed with the China National Intellectual Property Administration on May 30, 2022, patent application number 202210597120.9, with the title of the invention "Use of a tetrahydronaphthiridine derivative for producing a product that improves pigmentation." All contents of the said prior application are applied to this invention by reference.

[0002] [Technical Field] The present invention relates to the field of chemistry, more specifically to the use of tetrahydronaphthiridine derivatives for producing products that improve pigmentation, and more specifically to the use of tetrahydronaphthiridine derivatives for producing products that improve melasma.

[0003] [Background technology] Skin pigmentation is a difficult dermatological condition. For example, melasma, senile spots, freckles, melanosis, facial moles, and birthmarks not only affect appearance but also have a serious impact on people's lives. As people's living standards improve day by day, skin whitening, spot removal, and improvement of skin pigmentation are gradually becoming universal desires, and at the same time, there is a demand for the treatment of many skin diseases.

[0004] Melasma is a very common chronic, acquired skin disease characterized by increased facial melanin and hyperpigmentation. It frequently occurs in middle-aged women, primarily appearing as dark brown or yellowish-brown patches with varying shades and indistinct borders, distributed symmetrically across the cheeks, forehead, and jawline. It is also known as melasma or butterfly spots. While melasma usually has no noticeable symptoms and does not require treatment, it has a serious impact on appearance, causing both physical and psychological distress. With rising living standards, people are becoming more conscious of their appearance, and the treatment of skin diseases like melasma is receiving increasing attention.

[0005] Currently, the pathogenesis of melasma is not yet fully understood. Numerous studies suggest that genetic susceptibility, UV exposure, endocrine dysfunction, skin barrier dysfunction, hormonal changes, psychological factors, and nutritional levels are all closely related to the production of melasma. In actual treatment, since the area, severity, and degree of pigmentation of melasma differ from patient to patient, clinically, the skin damage caused by melasma is usually categorized and classified to formulate a comprehensive treatment plan. Currently, drug treatments for melasma include topical and systemic medications.

[0006] Topical medications generally have two aspects: protecting or restoring the skin's barrier function through functional skincare products, and suppressing and removing melanin in the damaged areas of melasma, primarily using topical medications for epidermal melasma. A representative drug is hydroquinone, which inhibits melanocyte DNA and RNA synthesis, competitively binds to tyrosinase, inhibits melanosome formation, or accelerates its breakdown. Higher concentrations result in a stronger depigmentation effect, but also greater skin irritation, causing burning sensations, and occasionally local allergic reactions. The usual concentration of hydroquinone is 2% to 5%. In 2002, the FDA approved triple combination cream (TCC), consisting of 4% hydroquinone, 0.01% fluocinolone, and 0.05% tretinoin, for the treatment of melasma, and it is now the first-line treatment for melasma. However, due to its many side effects, TCC should not be used for more than six months.

[0007] The most representative systemic drug is tranexamic acid (TXA). Tranexamic acid is a plasmin inhibitor and has recently shown good efficacy in treating melasma, including in oral, topical, and topical microneedle injection forms, demonstrating its ability to improve melasma. Tranexamic acid reduces α-melanocyte-stimulating hormone (α-MSH) by inhibiting plasmin, thereby reducing melanin production and competitively inhibiting tyrosinase activity in melanosomes, thus achieving a lightening effect on melasma. At the same time, tranexamic acid can inhibit angiogenesis and reduce erythema; some studies suggest that the improvement of melasma with tranexamic acid is related to its ability to inhibit the expression of endothelin-1 (ET-1). The use of tranexamic acid for melasma also has certain side effects, with headaches and severe abdominal distension reported with oral TXA administration, leading patients to abandon treatment due to unbearable symptoms. Topical TXA use has also resulted in adverse reactions such as erythema and burning sensations.

[0008] Currently, many options exist for improving melasma, but their effectiveness is not particularly ideal, the treatment period is very long, and the frequency of administration is relatively high, making it difficult to meet the ever-increasing clinical demand. Developing safer and more effective products for hyperpigmentation is a current concern.

[0009] [Summary of the Invention] One of the objects of the present invention is to provide the use of a compound represented by formula I, its pharmaceutically acceptable salts, hydrates, isomers, prodrugs, or mixtures thereof for producing products that improve pigmentation.

[0010] [ka]

[0011] However, R1 is selected from a carboxyl group, a phosphate group, and a sulfonic acid group; R2 is selected from hydrogen, a substituted or unsubstituted amino group, a substituted or unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C1-C6 alkoxy group, a C1-C4 haloalkyl group, a substituted or unsubstituted C3-C6 cycloalkyl group, a substituted or unsubstituted 4- to 8-membered aliphatic heterocyclic group, a substituted or unsubstituted 6- to 10-membered aryl group, or a substituted or unsubstituted 6- to 10-membered aromatic heterocyclic group.

[0012] In specific embodiments, R2 is hydrogen, unsubstituted, or optionally one, two or more R 2a The substituted groups are selected from amino groups, C1-C6 alkyl groups, C1-C6 alkoxy groups, C1-C4 haloalkyl groups, C3-C6 cycloalkyl groups, 4-8 member aliphatic heterocyclic groups, 6-10 member aryl groups, and 6-10 member aromatic heterocyclic groups.

[0013] In a specific embodiment, the R 2a These are selected from halogens, OH, NH2, NO2, CN, oxo (=O), C1-C6 alkyl groups, C1-C6 alkoxy groups, C3-C6 cycloalkyl groups, 4-8 member aliphatic heterocyclic groups, 6-10 member aryl groups, and 6-10 member aromatic heterocyclic groups.

[0014] In a specific embodiment, R2 is hydrogen, unsubstituted, or optionally one, two or more R 2a The substituted groups are selected from phenyl groups and phenyl-C1-C6 alkyl groups.

[0015] In a specific embodiment, R2 is hydrogen,

[0016] [ka]

[0017] They are selected from among them.

[0018] In a specific embodiment, the pigmentation may be a disease related to pigmentation. The disease related to pigmentation is a disease caused by the deposition of melanin on the surface of the skin, including chloasma, senile plaque, freckles, melanoma, facial mole, birthmark, etc.

[0019] In a specific embodiment, the disease related to the pigmentation is chloasma.

[0020] In a specific embodiment, the compound of formula I is selected from the compounds of the following chemical structures, their pharmaceutically acceptable salts, hydrates, isomers, prodrugs or mixtures:

[0021]

Chemical formula

[0022] In a specific embodiment, the pharmaceutically acceptable salt is the hydrochloride salt of the compound of formula I.

[0023] In a specific embodiment, the product for improving the pigmentation may be a pharmaceutical or a cosmetic.

[0024] In a specific embodiment, the product for improving the pigmentation refers to a clinically available pharmaceutical preparation produced with at least one of the compound of formula I, its pharmaceutically acceptable salt, hydrate, isomer, prodrug as an active ingredient and one or more pharmaceutically acceptable excipients. The pharmaceutical preparation according to the present invention can be produced and used in the form of oral preparations, external preparations, injections, etc.

[0025] 〔Effects of the Invention〕 This invention employs a rat model in which melasma is induced by 280-320nm UVB irradiation + progesterone injection. The compound is administered by local injection, and its effects are evaluated using apparent indicators, histopathological examination, and biochemical indicators. The results show that the compound of formula I of this invention effectively reduces the number of melanin granules in the skin surface cells of the rat molding area of ​​the melasma model, improves the morphology of skin tissue structure and inflammatory cell infiltration, and effectively reduces the levels of melasma-related biochemical indicators, indicating very good potential for application in the treatment of melasma.

[0026] [Brief explanation of the drawing] Figure 1 shows the effects of tranexamic acid and the test compounds on a rat model in which melasma was induced by UV irradiation + progesterone injection. Of these, (A) represents the overall skin condition of the rat test group; (B) represents the HE staining condition of the skin tissue of each group; (C) represents the distribution of melanin granules in the epidermal basal layer and basal layer in each group; (D) represents the expression of tyrosinase in the skin tissue of each group; (E) represents the observed grade of the apparent index of the melasma model; (F) represents the grade of melanin granule content in the melasma rat model after skin tissue collection on day 58; (G) represents the mean integrated optical density distribution of epidermal tyrosinase in each group after skin tissue collection on day 58; (H) represents the ET-1 content in the homogenate supernatant of skin tissue of each group after homogenate supernatant of skin tissue of each group of rats was collected on day 58; and (I) represents the weight change of each group of rats during the experimental period (Day 1 to Day 58). All scores and count results were obtained using a double-blind method. Compared to the control group, ***P<0.001; compared to the model group, #P<0.05, ##P<0.01, and ###P<0.001.

[0027] <Definitions and explanations of terms> Unless otherwise specified, the definitions of groups and terms set forth herein and in the claims may be combined and linked to one another in any way, including their definitions as examples, illustrative definitions, preferred definitions, definitions set forth in tables, and definitions of specific compounds in examples. Such combinations and linked definitions of groups and compound structures should be understood to be within the scope of the specification and / or claims of this application.

[0028] Unless otherwise specified, numerical ranges described herein and in the claims correspond to the descriptions of specific integer values. For example, the numerical range "1 to 40" corresponds to the integer values ​​in the numerical range "1 to 10," i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and the integer values ​​in the numerical range "11 to 40," i.e., 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40. Furthermore, when a numerical range is defined as a "number," it should be understood that it includes the two endpoints of that range, each integer within that range, and each decimal within that range. For example, "numbers from 0 to 10" should be understood not only as listing the integers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10, but also as listing the sums of each integer: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9, respectively.

[0029] In this specification, when describing one, two or more, “more than” should be understood to mean integers greater than two, such as three or more, e.g., 3, 4, 5, 6, 7, 8, 9, or 10.

[0030] The term "halogen" refers to fluorine, chlorine, bromine, and iodine.

[0031] "C1-C6 alkyl group" means a linear and branched alkyl group having 1, 2, 3, 4, 5, or 6 carbon atoms. The alkyl group is, for example, a methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, 2-methylbutyl group, 1-methylbutyl group, 1-ethylpropyl group, 1,2-dimethylpropyl group, neopentyl group, 1,1-dimethylpropyl group, 4-methylpentyl group, 3-methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 2-ethylbutyl group, 1-ethylbutyl group, 3,3-dimethylbutyl group, 2,2-dimethylbutyl group, 1,1-dimethylbutyl group, 2,3-dimethylbutyl group, 1,3-dimethylbutyl group, 1,2-dimethylbutyl group, or an isomer thereof.

[0032] The term "alkoxy group" means -O-(alkyl), where the definition of alkyl group is as described above. Non-limiting examples of alkoxy groups include methoxy, ethoxy, propoxy, and butoxy groups.

[0033] The term "C3-C6 cycloalkyl group" should be understood to mean a saturated monovalent monocyclic hydrocarbon ring having 3, 4, 5, or 6 carbon atoms. 3-10 The cycloalkyl group may be a monocyclic hydrocarbon group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group.

[0034] The term “4- to 8-membered aliphatic heterocyclic group” means a saturated ring or ring system unless otherwise defined, for example, a 4-, 5-, 6-, or 7-membered monoring, or a 7- or 8-membered diring (e.g., a fused ring, a bridging ring, or a spiroring), and comprising at least one heteroatom selected from O, S, and N, for example, 1, 2, 3, 4, 5 or more, where N and S may be oxidized to various oxidation states to form nitrogen oxides, -S(O)-, or -S(O)2-. The aliphatic heterocyclic group may be bonded to the rest of the molecule via any one of the carbon atoms or a nitrogen atom (if present). The aliphatic heterocyclic group may include fused or bridging rings and spirorings. In particular, examples of the aliphatic heterocyclic group include, but are not limited to, four-membered rings such as azetidinyl and oxetanyl groups, five-membered rings such as tetrahydrofuryl, dioxolanyl, pyrrolidinyl, imidazolyl, pyrazolyl, and pyrrolidinyl groups, six-membered rings such as tetrahydropyranyl, piperidinyl, morpholinyl, dithioalkyl, thiomorpholinyl, piperazinyl, and trithioalkyl groups, and seven-membered rings such as diazacycloheptyl.

[0035] The term "6-10 membered aryl group" preferably refers to monovalent aromatic or partially aromatic monocyclic or dicyclic rings having 6, 7, 8, 9, or 10 carbon atoms, particularly rings having 6 carbon atoms ("C6 aryl group"), such as a phenyl group or a biphenyl group, or rings having 9 carbon atoms ("C9 aryl group"), such as an indanyl group or an indenyl group, or rings having 10 carbon atoms ("C 10 The term "aryl group" should be understood to mean, for example, a tetrahydronaphthyl group, a dihydronaphthyl group, or a naphthyl group. When the aforementioned 6-10 membered aryl group is substituted, it can be monosubstituted or polysubstituted. Furthermore, the substitution site is not limited and may be, for example, ortho, para, or meta substitution.

[0036] The term "6-10 membered aromatic heterocyclic group" should be understood to include monovalent monocyclic or bicyclic (e.g., fused ring, bridging ring, spiro ring) aromatic ring systems having 6-10 ring atoms and containing 1-5 heteroatoms independently selected from N, O, and S, preferably 1-3 heteroatoms independently selected from N, O, and S. "Heteroaryl group" also means a group in which a heteroaromatic ring is fused with one or more aryl groups, alicyclic groups, or heterocyclic rings, where the bonded group or dot is on the heteroaromatic ring, and is selected from, for example, pyridyl, pyrimidinyl, pyrazinyl, pyridadinyl, and pyranyl groups.

[0037] [Modes for carrying out the invention] The following describes the technical aspects of the present invention in more detail by combining specific examples. The following examples are merely illustrative and should be understood as not limiting the scope of protection of the present invention. The technology realized based on the above-described aspects of the present invention is included within the scope of protection of the present invention.

[0038] Unless otherwise noted, all raw materials and reagents used in the following examples are commercially available or can be manufactured by known methods.

[0039] 1. Experimental Objective The therapeutic effect of the compound of the present invention on a rat melasma model was measured.

[0040] 2. Experimental materials and equipment

[0041] [Table 1]

[0042] [Table 2]

[0043] 3. Experimental Method 3.1 Molding: Before the start of the experiment, on Day 0, SD rats (purchased from Beijing Weitong Lihua Laboratory Animal Technology Co., Ltd., SPF grade, female, 7-8 weeks old, body weight 200±20g) were randomly divided into groups and numbered. The dorsal hair of each group of animals was first shaved using an electric shaver, and then short hairs on the skin were removed using depilatory cream to fully expose the dorsal skin. The area of ​​depilation was slightly larger than the actual molding area (5cm × 5cm). Each rat was depilated every 2-3 days to ensure complete exposure of the dorsal skin. The following day (Day 1), each group of rats was weighed, and their body weight was recorded after the reading on the electronic scale stabilized. Progesterone injection solution was administered intramuscularly to the base of the rats' thighs (alternating on both sides of the thigh) at a drug concentration of 20 mg / mL and an injection dose of 25 mg / kg, once daily. After intramuscular injection, ultraviolet light with a wavelength of 280-320 nm was irradiated onto the dorsal skin of rats. The light source was located approximately 30 cm away from the rats' dorsal skin, and the irradiation was continued for 60 minutes each time for a total of 4 weeks.

[0044] 3.2 Administration: After rat molding, multiple injections of tranexamic acid at a concentration of 5 mg / mL (positive control group) and test compound injections at concentrations of 5 mg / mL and 1.5 mg / mL (solvent: physiological saline) were administered to the skin wound sites using a 30G insulin needle, with a total volume of 0.05 mL / cm³. 2 The solvent was administered continuously every 5 days for 30 days to the control group (hair loss only, no molding treatment) and the model group.

[0045] 3.3 Detection Indicators: The first molding day was designated as Day 1, and the experimental cycle was continued for 58 days. After the experiment ended (Day 58), 1 hour after the final administration, the skin of the molding area of ​​each group of rats was photographed and used for apparent indicator scoring (see Table 1 for scoring criteria). Subsequently, each group of rats was euthanized, hair was removed from the back, and 0.5 g of full-thickness skin tissue from the hairless area on the back was taken. A 10% tissue homogenate was prepared by adding physiological saline to an ice bath, and the homogenate solution was centrifuged at 3000 r / min at room temperature for 10 minutes to obtain the skin tissue homogenate supernatant. Endothelin-1 expression in the rat skin tissue homogenate supernatant was detected by ELISA; skin from the molding area on the back of the rats was taken and fixed in 10% neutral formaldehyde at room temperature for 4 days. Four days later (Day 62), paraffin embedding and sectioning were performed, and paraffin sections of skin from each group of rats were obtained. HE staining was used to observe the pathological changes in the skin tissue of each group of rats. Staining method: The dried paraffin sections were dewaxed with the usual xylene method, hydrated with ethanol by descending a gradient, and washed with distilled water; the nuclei were stained with hematoxylin for 2 minutes, differentiated with hydrochloric acid and alcohol for a few seconds, and washed with water to return to blue; the stained sections were stained with eosin stain for 1 minute, and washed with water to remove residual stain; the sections were dehydrated and dried with gradient alcohol, cleared with xylene, sealed with neutral rubber, and then examined under a microscope. Epidermal hyperplasia, basal cell arrangement, presence or absence of inflammatory cell infiltration into the dermis, and changes in capillary number were observed in the skin tissue sections of each group using evaluation indicators. Skin pigmentation in each group of rats was observed using Fontana-Masson staining. Experimental method: After dewaxing and hydrating the sections, immerse them in Fontana silver nitrate solution and incubate in a 56°C incubator away from light for 30-40 minutes; wash 5-6 times with distilled water for 1-2 minutes each time; treat the sections with hypo solution for 1-5 minutes; rinse with tap water for 3-5 minutes; counterstain with neutral red dye for 5 minutes; rinse with tap water for 1 minute; dehydrate with 95% ethanol and anhydrous ethanol, clear with xylene, seal the sheets with neutral rubber, and then examine under a microscope. The distribution of melanin particles was scored (see Table 2 for scoring criteria). Tyrosinase expression in the skin of each group was detected immunohistochemically.Experimental method: 1) Baking: Place the prepared paraffin sections in an electric constant-temperature drying box and bake at 60°C for 3 hours; 2) Perform the usual xylene dewaxing on the dried paraffin sections, descend the gradient and hydrate with ethanol, then wash with distilled water; 3) Perform antigen retrieval; 4) Add 3% H2O2 dropwise and incubate at room temperature for 10 minutes to inactivate the endogenous enzyme, then wash three times with PBS for 3 minutes each time; 5) Block each section by adding normal goat immunoserum dropwise, incubate at room temperature for 10 minutes, shake off excess liquid, do not wash, add tyrosinase antibody (1:50) diluted in a fixed ratio, and refrigerate at 4°C. 1) The sections were refrigerated overnight; 6) After removing from the refrigerator and returning to room temperature, they were washed three times with PBS for 3 minutes each time; 7) Polymer enhancer (reagent A) was added to each section and washed three times with PBS for 3 minutes each time at room temperature for 20 minutes; 8) Enzyme-labeled anti-mouse rabbit polymer (reagent B) was added to each section and washed three times with PBS for 3 minutes each time at room temperature for 10 minutes; 9) DAB staining was performed, the reaction time was controlled under a microscope, hematoxylin counterstaining was performed, and the sections were thoroughly washed with distilled water to stop the staining; 10) The sections were dehydrated and dried with gradient alcohol, cleared with xylene, and sealed with neutral rubber; 11) Photographs were taken at 200x magnification using a phase-contrast microscope. The area and integrated optical density values ​​of the tyrosinase-positive region (stained region) were measured using ImageJ (1.8.0) software, and the average optical density value was calculated using the formula AOD = IOD / Area.

[0046] [Table 3]

[0047] [Table 4]

[0048] 3.4 Experimental data were expressed as mean ± SD. Statistical analysis of group differences was performed using one-way ANOVA and Tukey's test, while scoring data was analyzed using the Mann-Whitney U test. A p-value of 0.05 or less indicated a statistically significant difference.

[0049] 3.5 Preparation of Test Compounds Manufacturing Example 1

[0050] [ka]

[0051] Step 1: Preparation of tert-butyl 2-chloro-7,8-dihydro-1,6-naphthyridine-6(5H)-carboxylate 0.9 g of 2-chloro-5,6,7,8-tetrahydro-1,6-naphthirizine hydrochloride was weighed and suspended in 15 mL of dichloromethane. After liberating 1.4 g of N,N-diisopropylethylamine, 1.15 g of di-tert-butyl dicarbonate was added and the mixture was reacted at room temperature for 1 hour. TLC indicated that the starting material had been completely consumed, and the title compound (1.12 g) was obtained by column chromatography.

[0052] [ka]

[0053] MS(ESI)m / z(M+H) + =269.0.

[0054] Step 2: Preparation of tert-butyl 2-cyano-7,8-dihydro-1,6-naphthyridine-6(5H)-carboxylate 1.12 g of tert-butyl 2-chloro-7,8-dihydro-1,6-naphthyridine-6(5H)-carboxylate was weighed and dissolved in 20 mL of N,N-dimethylformamide. 2.44 g of zinc cyanide and 483 mg of tetrakis(triphenylphosphine)palladium were added, and the mixture was purged with argon three times and reacted at 120°C for 3 hours. TLC indicated that the starting materials had been completely consumed. The mixture was diluted with ethyl acetate, filtered through diatomaceous earth, extracted twice with ethyl acetate, washed once with saturated brine, dried over anhydrous sodium sulfate, and purified by column chromatography to obtain the title compound (1.1 g).

[0055] [ka]

[0056] MS(ESI)m / z(M+H)+=260.0.

[0057] Step 3: Production of 5,6,7,8-tetrahydro-1,6-naphthyrizine-2-carboxylate hydrochloride 1.1 g of tert-butyl 2-cyano-7,8-dihydro-1,6-naphthirizine-6(5H)-carboxylate was weighed and dissolved in 25 mL of 6 M hydrochloric acid solution, and the mixture was reacted overnight at 120°C. LC-MS indicated that the starting material had been completely consumed, and the reaction solution was concentrated until dry. 5,6,7,8-tetrahydro-1,6-naphthirizine-2-carboxylate hydrochloride (test compound 1,726 mg) was separated by pre-HPLC to obtain the product.

[0058] [ka]

[0059] MS(ESI)m / z(M+H)+=179.0.

[0060] 1 HNMR (400MHz, Methanol-d4) δ8.21(d,J=8.1Hz,1H),8.12(d,J=8.0Hz,1H),4.60(s,2H),3.71(t,J=6.4Hz,2H),3.42(t,J=6.4Hz,2H).

[0061] Manufacturing Example 2 Step 1: Preparation of tert-butyl 2-chloro-7,8-dihydro-1,6-naphthyridine-6-(5H)-carboxylate

[0062] [ka]

[0063] 0.9 g of 2-chloro-5,6,7,8-tetrahydro-1,6-naphthirizine hydrochloride was suspended in 15 mL of dichloromethane, 1.4 g of N,N-diisopropylethylamine was added, followed by 1.15 g of di-tert-butyl dicarbonate, and the mixture was reacted at room temperature for 1 hour. TLC showed that the starting materials had been completely consumed. The reaction mixture was diluted with water, extracted with dichloromethane, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated. The resulting crude product was purified by column chromatography to obtain the target compound (1.12 g). MS(ESI)m / z(M+H)+=269.0.

[0064] Step 2: Preparation of tert-butyl 2-(diethoxyphosphoryl)-7,8-dihydro-1,6-naphthylpyridine-6(5H)-carboxylate

[0065] [ka]

[0066] Under an argon atmosphere, tert-butyl 2-chloro-7,8-dihydro-1,6-naphthyridine-6(5H-carboxylate) (100 mg) was dissolved in toluene (20 mL), and diethyl phosphite (102 mg), tris(dibenzalacetone)dipalladium (34 mg), 1,1'-bis(diphenylphosphine)ferrocene (41 mg), and triethylamine (75 mg) were added. The system was reacted overnight at 120 °C. TLC indicated that the starting materials were completely consumed. The mixture was diluted with ethyl acetate, filtered with diatomaceous earth, and the filtrate was collected and concentrated. The crude product was purified by Prepared°TLC to obtain the target compound (70 mg). MS(ESI)m / z(M+H)+=371.1.

[0067] Step 3: Preparation of (5,6,7,8-tetrahydro-1,6-naphthyrizin-2-yl)phosphonate (Test Compound 2)

[0068] [Chemical formula]

[0069] tert-Butyl 2-(diethoxyphosphoryl)-7,8-dihydro-1,6-naphthylpyridine-6(5H)-carboxylate (70 mg) was dissolved in concentrated hydrochloric acid (5 mL) and reacted at 100 °C overnight. LCMS indicated that the raw material was completely consumed. The reaction solution was concentrated, and the crude product was purified by pre-HPLC to obtain the target compound (30 mg). MS (ESI) m / z (M+H)+ = 215.0.

[0070] 1 1H-NMR (400 MHz, D2O) δ 8.35 (dd, J = 8.0, 2.4 Hz, 1H), 8.06 (t, J = 7.7 Hz, 1H), 4.59 (s, 2H), 3.67 (t, J = 6.0 Hz, 2H), 3.49 (t, J = 6.4 Hz, 2H).

[0071] Production Example 3 (1) Production of 2-methyl-N-(4-phenylbutylene)propan-2-sulfenamide 4-Phenylbutanol (7.6 mL) was dissolved in dichloromethane (200 mL), and 2-iodobenzoylbenzoic acid (28.00 g), tert-butylsulfenamide (9.07 g), anhydrous magnesium sulfate (30.80 g), and pyridinium 4-methylbenzenesulfonate (0.627 g) were added sequentially. The mixture was heated to 40 °C, reacted for 24 hours, cooled to room temperature, suction filtered, the filter cake was washed with dichloromethane, the filtrate was concentrated until dry, and purified by column chromatography to obtain the title compound (5.1 g).

[0072] [Chemical formula]

[0073] MS (ESI) m / z (M+H)+ = 252.1.

[0074] (2) Preparation of N-(1-(3-bromo-6-methoxypyridine-2-yl)-5-phenylpentan-2-yl)-2-methylpropane-2-sulfenamide 4.85 g of 3-bromo-6-methoxy-2-methylpyridine was weighed into a dry reaction flask, and 100 mL of anhydrous tetrahydrofuran was added under a nitrogen atmosphere. The mixture was cooled to -78°C. 12.00 mL of a tetrahydrofuran solution of lithium diisopropylamide (2.0 M) was added dropwise, and the mixture was reacted at -78°C for 40 minutes. 20 mL of tetrahydrofuran containing 5.02 g of 2-methyl-N-(4-phenylbutylene)propane-2-sulfenamide was added dropwise, and the mixture was reacted at -30°C for 30 minutes, after which the temperature was slowly raised to room temperature. LC-MS detected completion of the reaction, and the mixture was quenched with saturated ammonium chloride solution. Ethyl acetate and water were added, liquid-liquid extraction was performed, and the organic phase was concentrated until dry. The compound was purified by column chromatography to obtain the title compound (7.15 g).

[0075] [ka]

[0076] MS(ESI)m / z(M+H) + =453.1, 455.1.

[0077] (3) Preparation of 2-(2-((tert-butylsulfinyl)amino)-5-phenylpentyl)-6-methoxynicotinate ethyl N-(1-(3-bromo-6-methoxypyridine-2-yl)-5-phenylpentan-2-yl)-2-methylpropane-2-sulfenamide (5.42 g) was weighed and dissolved in ethanol (150 mL). [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloromethane dichloride complex (0.979 g) and N,N-diisopropylethylamine (4.12 mL) were added, the system was ventilated with carbon monoxide, and the reaction was carried out overnight under reflux in a carbon monoxide atmosphere, followed by desolvation under reduced pressure. The compound was purified by column chromatography to obtain the title compound (2.01 g).

[0078] [ka]

[0079] MS(ESI)m / z(M+H) + =447.2.

[0080] (4) Preparation of 2-methoxy-7-(3-phenylpropyl)-7,8-dihydro-1,6-naphthyrizine-5(H)-one 2.00 g of ethyl 2-(2-((tert-butylsulfinyl)amino)-5-phenylpentyl)-6-methoxynicotinate was weighed and dissolved in acetonitrile (50 mL), and cesium carbonate (5.87 g) was added. The mixture was heated to 80°C and stirred overnight, and LC-MS was used to monitor the completion of the reaction. The mixture was cooled to room temperature, filtered by suction, the filtrate was washed with dichloromethane, the filtrate was concentrated until dry, and purified by column chromatography to obtain the title compound (1.1 g).

[0081] [ka]

[0082] MS(ESI)m / z(M+H) + =297.1.

[0083] (5) Preparation of 2-methoxy-7-(3-phenylpropyl)-5,6,7,8-tetrahydro-1,6-naphthyridine 1.10 g of 2-methoxy-7-(3-phenylpropyl)-7,8-dihydro-1,6-naphthyrizine-5(6H)-one was weighed and dissolved in 70 mL of tetrahydrofuran. 0.562 g of lithium aluminum hydride was added under ice bath conditions, and the mixture was stirred at 70°C for 8 hours. LC-MS was used to monitor the completion of the reaction. 0.56 mL of water, 0.56 mL of 15% sodium hydroxide solution, and 1.68 mL of water were added dropwise under ice bath conditions, and the mixture was stirred at room temperature for 20 minutes. The mixture was then dried over anhydrous magnesium sulfate, filtered by suction, washed with dichloromethane, and concentrated under reduced pressure until dry. The compound was purified by column chromatography to obtain the title compound (0.41 g).

[0084] [ka]

[0085] MS(ESI)m / z(M+H) + =283.2.

[0086] (6) Preparation of 7-(3-phenylpropyl)-5,6,7,8-tetrahydro-1,6-naphthyrizin-2-ol 0.40 g of 2-methoxy-7-(3-phenylpropyl)-5,6,7,8-tetrahydro-1,6-naphthiridine was weighed, 5 mL of hydrobromic acid solution was added, the mixture was heated to 80°C and stirred for 5 hours, the solvent was removed under reduced pressure, ethyl acetate was added and beaten, filtered, and dried to obtain the title compound (0.295 g).

[0087] [ka]

[0088] MS(ESI)m / z(M+H) + =269.1.

[0089] (7) Preparation of 2-chloro-7-(3-phenylpropyl)-5,6,7,8-tetrahydro-1,6-naphthyridine 7-(3-phenylpropyl)-5,6,7,8-tetrahydro-1,6-naphthyrizin-2-ol (0.29 g) was weighed, phosphorus oxychloride (6 mL) was added, the mixture was heated to 100°C and stirred for 10 hours, the solvent was removed under reduced pressure, ice water and dichloromethane were added, the pH was adjusted to 9-10 with aqueous Na2CO3 solution, liquid-liquid extraction was performed, and the organic phase was concentrated until dry to obtain the crude product (0.6 g) of the title compound.

[0090] [ka]

[0091] MS(ESI)m / z(M+H) + =287.1.

[0092] (8) Preparation of tert-butyl 2-chloro-7-(3-phenylpropyl)-7,8-dihydro-1,6-naphthyridine-6-(5H)-carboxylate 0.6 g of 2-chloro-7-(4-methoxyphenethyl)-5,6,7,8-tetrahydro-1,6-naphthyridine was weighed and dissolved in 5 mL of dichloromethane and 5 mL of water. Sodium carbonate solution was added to adjust the pH to 8-9, and 0.50 mL of di-tert-butyl dicarbonate was added. The mixture was stirred at room temperature for 1 hour, concentrated under reduced pressure until dry, and purified by column chromatography to obtain the title compound (0.22 g).

[0093] [ka]

[0094] MS(ESI)m / z(M+H) + =387.1.

[0095] (9) Preparation of tert-butyl 2-(benzylthio)-7-(3-phenylpropyl)-7,8-dihydro-1,6-naphthylpyridine-6(5H)-carboxylate 147 mg of tert-butyl 2-chloro-7-(3-phenylpropyl)-7,8-dihydro-1,6-naphthyridine-6-(5H)-carboxylate, 71 mg of benzyl mercaptan, 35 mg of tris(dibenzylidene indenacetone)dipalladium, 4,5-bisdiphenylphosphine-9,9-dimethylxanthene, and 113 μL of triethylamine were weighed into a reaction bottle. 5 mL of 1,4-dioxane was added, the mixture was purged with nitrogen, and the reaction was carried out overnight at 100°C. The mixture was concentrated under reduced pressure until dry, and purified by column chromatography to obtain the title compound (159 mg).

[0096] [ka]

[0097] MS(ESI)m / z(M+H) + =475.2.

[0098] (10) Preparation of tert-butyl 2-(chlorosulfonyl)-7-(3-phenylpropyl)-7,8-dihydro-1,6-naphthyridine-6(5H)-carboxylate 156 mg of tert-butyl 2-(benzylthio)-7-(3-phenylpropyl)-7,8-dihydro-1,6-naphthylpyridine-6(5H)-carboxylate was weighed and dissolved in 5 mL of acetonitrile. Acetic acid (79 mg), water (48 mg), and 1,3-dichloro-5,5-dimethylhydantoin (130 mg) were added sequentially under ice bath conditions. The mixture was stirred in the ice bath for 1 hour, ice water and dichloromethane were added, and the mixture was extracted by liquid-liquid extraction. The organic phase was concentrated until dry to obtain the crude product of the title compound (148 mg).

[0099] [ka]

[0100] MS(ESI)m / z(M+H) + =451.1.

[0101] (11) Preparation of sodium 6-(tert-butoxycarbonyl)-7-(3-phenylpropyl)-5,6,7,8-tetrahydro-1,6-naphthyrizine-2-sulfonate 148 mg of tert-butyl 2-(chlorosulfonyl)-7-(3-phenylpropyl)-7,8-dihydro-1,6-naphthyrizine-6(5H)-carboxylate was weighed and dissolved in 5 mL of tetrahydrofuran and 5 mL of water. 27 mg of sodium hydroxide was added, and the mixture was stirred at 80°C for 1 hour. Ethyl acetate and water were added, and the mixture was separated by liquid-liquid extraction. The organic phase was discarded, and the aqueous phase was concentrated until dry to obtain a crude product (50 mg) of the compound described in the title.

[0102] [ka]

[0103] MS(ESI)m / z(M+H) + =433.1.

[0104] (12) Preparation of 7-(3-phenylpropyl)-5,6,7,8-tetrahydro-1,6-naphthyrizine-2-sulfonate Crude (tert-butoxycarbonyl)-7-(3-phenylpropyl)-5,6,7,8-tetrahydro-1,6-naphthyrizine-2-sulfonate sodium (50 mg) was taken, dissolved in 6 M hydrochloric acid solution (3 mL), stirred at room temperature for 1 hour, concentrated until the system was dry, and separated by pre-HPLC to obtain the title compound (test compound 3, 2.25 mg).

[0105] [ka]

[0106] MS(ESI)m / z(M+H) + =333.0.

[0107] 1H NMR(400MHz,D2O)δ7.74(dd,J=18.5,8.1Hz,2H),7.24(ddd,J=21.9,14.9,7.3Hz,5H),4.42(s,2H), 3.72-3.62(m,1H),3.32-3.22(m,1H),3.01-2.92(m,1H),2.63(d,J=3.6Hz,2H),1.83-1.58(m,4H).

[0108] 4. Experimental Results Using the experimental method described above, the pharmacological activity of the test compound of the present invention was verified, and statistical analysis of apparent, biochemical, and pathological indicators showed that the application of the test compound of the present invention can effectively reduce skin pigmentation in rats and has a clear improvement effect on melasma symptoms in model rats.

[0109] The experimental data collected was analyzed on day 58, i.e., the final day of the experiment, according to the experimental methods described in sections 3.1 to 3.4. The specific results are shown in Figure 1.

[0110] 4.1 The following results were obtained from the classification evaluation of apparent indicators in Figures 1A and 1E. No significant changes were observed in the dorsal skin of the control group rats; the model group rats showed clear dark brown skin damage areas, and the skin damage area was large; compared to the model group, the skin damage areas of the 5 mg / mL tranexamic acid and test compound group rats were all noticeably lighter in color, becoming light brown, and the skin damage area was significantly reduced (P<0.05).

[0111] 4.2 The following can be observed from the HE staining results in Figure 1B: The epidermal tissue structure of the control group rats was complete, the arrangement of stratum corneum cells was orderly, there was no obvious proliferation of fibers, and there was no infiltration of inflammatory cells; the epidermal tissue of the model group rats showed a clear increase in the thickness of the granular layer, spinous layer and stratum corneum, disorder in the arrangement of the skin tissue, heterogeneity in distribution, and infiltration of inflammatory cells compared to the control group rats; the 5 mg / mL tranexamic acid and test compound groups showed a clear decrease in the thickness of the basal layer and spinous layer of the epidermal tissue compared to the model group, the arrangement of the skin tissue structure became gradually flatter, and the phenomenon of inflammatory cell infiltration improved.

[0112] 4.3 As shown in Figure 1C, Fontana-Masson staining results indicate that positive melanin particle expression appears black, and cell nuclei appear red; there were almost no black-positive areas in the stained sections of the control group; the epidermal sections of the model group showed the largest area of ​​black-positive regions, the darkest color, and a continuous banded distribution, with a clear increase in melanin particles. Numerous melanin particles with a continuous banded distribution appeared in the basal cells and stratum spinosum, and densely distributed melanin particles and melanin caps appeared in the epidermal layer; Figure 1F Melanin particles in rat skin tissue A grade evaluation was performed on the content of each compound. In the 5 mg / mL tranexamic acid group, compared to the model group, the area of ​​the black-positive region in the section was reduced, the color became lighter, and a decrease in melanin particles in the skin tissue was observed. The distribution of melanin particles was band-like, but mainly concentrated in the basal layer and spinous layer. In the 5 mg / mL test compound 1 and 3 groups, compared to the model group, the area of ​​the black-positive region in the section was significantly reduced, the color became significantly lighter, the number of melanin particles in the skin tissue decreased significantly, and discontinuous distribution of melanin particles was observed only in the basal layer.

[0113] 4.4 Immunohistochemical tyrosinase color development results in Figures 1D and 1G showed that tyrosinase-positive expression appeared yellowish-brown, and cell nuclei appeared blue; there were almost no yellowish-brown areas in the immunohistochemical sections of the control group, indicating low tyrosinase expression in rat skin tissue; the area of ​​tyrosinase-positive regions was largest in the rat skin tissue sections of the model group, and the yellowish-brown color was clearly visible, indicating a high tyrosinase positivity rate in the rat skin tissue of the model group; compared to the model group, the area of ​​tyrosinase-positive expression regions in skin tissue sections of 5 mg / mL tranexamic acid, test compound 1 group and test compound 3 group were significantly reduced, the color was clearly lighter, and the tyrosinase positivity rate in skin tissue was significantly lower (P<0.001); all of the test compounds 1.5 and 5 mg / mL showed significant differences compared to the model group (P<0.01).

[0114] 4.5 The ET-1 content of the skin tissue homogenate in Figure 1H was measured using the ELISA method. The ET-1 content in the skin tissue of the model rat group was significantly increased compared to the control group, while the content in the 5 mg / mL tranexamic acid and test compound groups was clearly decreased compared to the model group, with a statistically significant difference (P<0.01).

[0115] 4.6 Figure 1I shows that there were no significant differences in body weight among the rat groups throughout the entire experiment, indicating that the animals have good tolerance to the test substance.

[0116] The embodiments of the technical proposal of the present invention have been described exemplarily above. It should be understood that the scope of the present invention is not limited to the embodiments described above. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the claims of this application. [Brief explanation of the drawing]

[0117] [Figure 1] Figure 1 shows the effects of tranexamic acid and the test compounds on a rat model in which melasma was induced by UV irradiation + progesterone injection. Of these, (A) represents the overall skin condition of the rat test group; (B) represents the HE staining condition of the skin tissue of each group; (C) represents the distribution of melanin granules in the epidermal basal layer and basal layer in each group; (D) represents the expression of tyrosinase in the skin tissue of each group; (E) represents the observed grade of the apparent index of the melasma model; (F) represents the grade of melanin granule content in the melasma rat model after skin tissue collection on day 58; (G) represents the mean integrated optical density distribution of epidermal tyrosinase in each group after skin tissue collection on day 58; (H) represents the ET-1 content in the homogenate supernatant of skin tissue of each group after homogenate supernatant of skin tissue of each group of rats was collected on day 58; and (I) represents the weight change of each group of rats during the experimental period (Day 1 to Day 58). All scores and count results were obtained using a double-blind method. Compared to the control group, ***P<0.001; compared to the model group, #P<0.05, ##P<0.01, and ###P<0.001.

Claims

1. The use of a compound represented by formula I, its pharmaceutically acceptable salt, hydrate, or mixture thereof, for the manufacture of a product for improving hyperpigmentation. 【Chemistry 1】 However, R １ is selected from a carboxyl group, a phosphate group, and a sulfonic acid group; R ２ is hydrogen, a substituted or unsubstituted amino group, a substituted or unsubstituted C １ to C ６ alkyl group, a substituted or unsubstituted C １ to C ６ alkoxy group, a C １ to C ４ haloalkyl group, a substituted or unsubstituted C ３ to C ６ cycloalkyl group, a substituted or unsubstituted 4- to 8-member aliphatic heterocyclic group, a substituted or unsubstituted 6- to 10-member aryl group, or a substituted or unsubstituted 6- to 10-member aromatic heterocyclic group.

2. R ２ R is hydrogen, unsubstituted or any one, two or more R atoms. ２ａ The amino group, C, is substituted with １ ~C ６ alkyl group, C １ ~C ６ Alkoxy group, C １ ~C ４ Haloalkyl group, C ３ ~C ６ Selected from cycloalkyl groups, 4-8 membered aliphatic heterocyclic groups, 6-10 membered aryl groups, and 6-10 membered aromatic heterocyclic groups, The aforementioned R ２ａ Halogen, OH, NH ２ NO ２ CN, oxo (=O), C １ ~C ６ alkyl group, C １ ~C ６ Alkoxy group, C ３ ~C ６ The use according to claim 1, characterized in that it is selected from a cycloalkyl group, a 4- to 8-membered aliphatic heterocyclic group, a 6- to 10-membered aryl group, and a 6- to 10-membered aromatic heterocyclic group.

3. The aforementioned R ２ R is hydrogen, unsubstituted or any one, two or more R atoms. ２ａ A phenyl group substituted with phenyl-C １ -C ６ The use according to claim 1, characterized in that it is selected from alkyl-.

4. The aforementioned R ２ is hydrogen, 【Chemistry 2】 The use according to claim 1, characterized by being selected from among.

5. The use according to claim 1, characterized in that the compound of formula I is selected from compounds having the following chemical structures, pharmaceutically acceptable salts, hydrates, or mixtures thereof. 【Transformation 3】

6. The use according to claim 1, characterized in that the pharmaceutically acceptable salt is the hydrochloride salt of the compound of formula I.

7. The use according to any one of claims 1 to 6, wherein the aforementioned pigmentation may be a disease related to pigmentation, and the aforementioned disease related to pigmentation refers to a disease caused by the deposition of melanin in the superficial layer of the skin.

8. The use according to claim 7, characterized in that the disease associated with the pigmentation includes one or more of melasma, senile plaques, freckles, melanosis, facial moles, and birthmarks.

9. The use according to claim 7, characterized in that the disease related to the aforementioned pigmentation is melasma.

10. The use according to any one of claims 1 to 6, characterized in that the product for improving the aforementioned pigmentation may be a pharmaceutical or a cosmetic.

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