KR101916106B1 - Synthetic method for 2,5-diaryloxazole compounds and anti-inflammatory pharmaceutical compounds containing the 2,5-diaryloxazole compounds - Google Patents

Abstract

The present inventors have invented an effective synthesis method for a 2,5-diaryloxazole compound from a commercially available starting material. The synthesis method uses the Delepine reaction and the Robinson-Gabriel reaction as main steps. For oxazole compounds synthesized in the present invention, the present inventors have evaluated the inhibitory effect of LPS-induced NO production in RAW 264.7 cells, and have found that the oxazole compounds of the present invention significantly inhibit NO production in a concentration-dependent manner. Therefore, the oxazole compounds of the present invention may be potential compounds which can be used as anti-inflammatory agents.

Description

TECHNICAL FIELD The present invention relates to a method for synthesizing a 2,5-diaryloxazole compound and an antiinflammatory pharmaceutical composition containing the compound,

The present invention relates to a method for synthesizing a 2,5-diaryloxazole compound and an antiinflammatory activity of the synthesized 2,5-diaryloxazole compound.

Inflammation is a protective and appropriate physiological response induced by intrinsic and extrinsic damage, such as infection or injury. However, dysregulation of this response may cause a variety of pathological conditions including cardiovascular disease, rheumatoid arthritis, bronchitis, diabetes, neurodegenerative diseases and cancer (1, 2). Activated macrophages, lymphocytes and neutrophils are involved in the pathogenesis of acute and chronic inflammatory diseases. The activated macrophages are composed of a large number of macrophages such as nitric oxide (NO), leukotriene (LT), prostaglandin (PG) and interleukin-lb (IL-1?), Cytokines such as IL-6 and tumor necrosis factor? Secrete a powerful bioactive inflammatory mediator (3, 4). Current methods for relieving inflammation mainly rely on corticosteroids, nonsteroidal anti-inflammatory analgesics (NSAIDs), selective COX-2 inhibitors (COXIBs) and antihistamines, which are the synthesis of mediators that induce host responses to injury Lt; / RTI > Despite the remarkable success of such small molecule inhibitors, it still involves problems such as gastric ulcers, renal toxicity, joint destruction, and cardiovascular disease (5). Therefore, a new anti-inflammatory agent is desperately required.

Nitric oxide (NO), a gaseous free radical produced by nitric oxide synthase (NOS), plays an important role in the pathogenesis of inflammation, and the role of NO in this process is strongly dependent on its concentration.

Under normal physiological conditions, NO has an anti-inflammatory effect. However, excessive production of NO by inducible NOS is associated with the pathogenesis of the aforementioned inflammatory diseases (6). Thus, tissue and / or site-specific inhibition of NO will open a new pathway for future management of inflammation-based diseases.

Oxazole, a 5-atom heterocyclic aromatic compound, is one of the important skeletons present in compounds and natural products that exhibit various biological activities (7, 8). In recent years, oxazole research has received considerable attention in academia and industry in terms of various pharmacological properties such as antibacterial, antiviral, antifungal, anti-cancer, anti-inflammatory, anti-tuberculosis, anti-HIV and analgesic agents. Some oxazoles showed enzyme inhibitory activity (9, 10). It has been reported that substituted oxazoles can be used as agrochemicals, fluorescent dyes, corrosion inhibitors, and can be applied in the photographic and polymer industries (9). In addition, substituted oxazoles can play an important role in organic synthesis (11). In particular, 2,5-substituted aryl or alkyloxazoles are the basic skeletons found in many natural products and medicines (12).

Nathan C., Ding A., Cell 140, 871-882 (2010). Libby P. Nutr. Rev. 65, 140-146 (2007). Turner M. D. et al., Biochim. Biophys. Acta 1843 2563-2582 (2014). Ostuni R. et al., Cell. Mol. Life Sci. 67, 4109-4134 (2010). Gilroy D. W. et al., Nat. Rev. Drug Discov. 3, 401-416 (2004). Lo Faro M. L. et al., Nitric oxide 41, 38-47 (2014). Palmer D. C., " The Chemistry of Heterocyclic Compounds. Oxazoles: Synthesis, Reactions, and Spectroscopy " Part A. Vol. 60, John Wiley & Sons, Hoboken, NJ, 2003. Jin Z., Nat. Prod. Rep. 30, 869-915 (2013). Ibrar A. et al., RSC Adv. 6, 93016-93047 (2016). Senger J. et al., J. Med. Chem. 59,1545-1555 (2016). Yeh V. S. C. Tetrahedron 60, 11995-12042 (2016). Chatterjee T. et al., J. Org. Chem. 81, 6995-7000 (2016). Banzragchgarav O. et al., J. Nat. Prod. 79, 2933-2940 (2016). Jang H. Y. et al., Bioorg. Med. Chem. Lett., 26, 5438-5443 (2016). Damodar K. et al., Tetrahedron Lett. 58, 50-53 (2017). Wang Z., " Comprehensive Organic Name Reactions and Reagents, Delepine reaction " John Wiley & Sons, Vol. 1, ch. 185, 2010, p. 865. Pulici M. et al., J. Comb. Chem. 7, 463-473 (2005). Salerno L. et al., Curr. Pharm. Des. 8, 177-200 (2002).

The present invention aims at providing a method for efficiently synthesizing a 2,5-diaryloxazole compound and confirming the biological activity of the synthesized 2,5-diaryloxazole compound.

1 is a chemical structural formula of 2,5-diaryloxazole (Compound 1-5) and derivatives thereof. Compounds 2 and 4 are oxytropis lanata ) 13 and compound 2 exhibited the strongest trypanocidal activity (IC ₅₀ 1.0 μM), while compounds 1, 3 and 5 were synthetic oxazol. The present invention relates to an efficient synthesis method of oxazole compounds 1-5 and to biological activities in vitro.

The route of synthesis of 2,5-diaryloxazole compounds 1-5 is summarized in Fig. Bromination reaction of 2'-methoxyacetophenone (Compound 6) using CuBr ₂ , 2'-methoxyphenacyl bromide (Compound 7a) was obtained in 96% yield. Next, compound 7a and phenacyl bromide (compound 7b) were subjected to Delepine reaction conditions (16). The bromine compound 7a or 7b was treated with hexamethylenetetramine to obtain a quaternary salt. After acid hydrolysis, 4-methoxybenzoylmethylammonium chloride (compound 8a) and benzoylmethylammonium chloride (compound 8b) were dissolved in 88% 97% yield.

Substituted benzoyl chlorides resulting from the corresponding benzoic acids (compounds 9a-9d) are then reacted with compound 8a or 8b in the presence of pyridine to give 2-acylamino-ketones, followed by the Robinson-Gabriel dehydrocyclization reaction, (17), the corresponding 2,5-diaryloxazole compound 1 and compounds 10a-10c were obtained in 47-61% yield over three steps.

Finally, when 1.0 M BBr ₃ solution was added to Compound 1 and 10a-10c, Compound 2-5 was produced in a yield of 88-98%, respectively. All the target compounds 1-5 were identified by NMR ( ¹ H- and ¹³ C-) and MS data.

The present inventors have invented a method for efficiently synthesizing a 2,5-diaryloxazole compound (1-5) having a total yield of 38-48% from a commercially available starting material. This synthesis led to the Delpine and Robinson-Gabriel reactions. The present inventors evaluated oxazole compounds synthesized in the present invention by evaluating the inhibitory effect of LPS-induced NO production in RAW 264.7 cells and found that the oxazole compounds of the present invention inhibit NO production remarkably in a concentration-dependent manner. In the present invention, Compound 3 (70.7%; IC ₅₀ = 2.33 [mu] M) exhibited more potent NO production inhibitory activity than the positive control L-NMMA (79.3%; IC ₅₀ = 4.51 μM). Compound 5 (68.3%; IC ₅₀ = 2.30 μM) and Compound 2 (53.9%; IC ₅₀ = 6.31 [mu] M) showed inhibitory activity. The compound 3 of the present invention may be a potential compound as an anti-inflammatory agent targeting NO production.

The present invention

(A) Hexamethylenetetramine was added to compound 7a represented by formula (7) and phenacyl bromide (compound 7b), respectively, and reacted at room temperature overnight to obtain a quaternary ammonium salt to give a quaternary ammonium salt, Methoxybenzoylmethylammonium chloride (Compound 8a) represented by Chemical Formula 8 was reacted with Compound 7b to obtain benzoylmethylammonium chloride (Compound 8b) represented by Chemical Formula 8 from compound 7b, and acid hydrolysis reaction was carried out with refluxing with hydrochloric acid and ethanol, ; And

(B) Substituted benzoyl chlorides formed from the benzoic acid compounds 9a-9d represented by the general formulas (9a), (9b), (9c) and (9d) are reacted with the compound 8a or 8b in the presence of pyridine, and a Robinson-Gabriel dehydration cyclodehydration To obtain 2,5-diaryloxazole represented by the general formula (1) and 2,5-diaryloxazole represented by the general formulas (10a), (10b) and (10c) from the benzoic acid compound represented by the compounds 9a, 9b, 9c and 9d; To a process for synthesizing 2,5-diaryloxazole compounds.

≪ Formula 1 >

≪ Formula 7 >

(8)

<Formula 9a>

<Formula 9b>

<Formula 9c>

<Formula 9d>

<Formula 10a>

&Lt; Formula 10b >

&Lt; Formula 10c >

In addition, the present invention is characterized in that after the step (b)

(C) A solution of BBr ₃ is added to the 2,5-diaryloxazole represented by the above general formula (1) and the general formulas (10a), (10b) and (10c) to demethylate the 2,5-diaryloxazole -5 &lt; / RTI &gt; in the presence of a catalyst.

(2)

(3)

&Lt; Formula 4 >

&Lt; Formula 5 >

The present invention is further characterized in that the compound 7a is obtained by? -Brominating 2'-methoxyacetophenone using CuBr ₂ .

Further, the present invention is characterized in that the phenacyl bromide is obtained by deprotecting a methoxy group in the compound 7a.

Further, the present invention is characterized in that the Robinson-Gabriel dehydration cyclization reaction is carried out by adding H ₂ SO ₄ and Ac ₂ O.

In addition to this, the present invention also relates to the use of 2- (2,3-dimethoxyphenyl) -5- (2-methoxyphenyl) oxazole, 3- (5- (2- Benzene-1,2-diol, 2,2 '- (oxazole-2,5-diyl) diphenol, 2- (2- (3- hydroxyphenyl) oxazol- And 3- (5-phenyloxazol-2-yl) benzene-1,2-diol.

The pharmaceutical composition containing at least one of the 2,5-diaryloxazole compounds 1-5 of the present invention as an active ingredient may be formulated together with a carrier usually accepted in the pharmaceutical field and administered orally or by injection And the like. Oral compositions include, for example, tablets and gelatin capsules, which may contain, in addition to the active ingredient, a diluent such as lactose, dextrose, sucrose, mannitol, sorbitol, cellulose and / or glycine, , Magnesium stearate, stearic acid and its magnesium or calcium salt and / or polyethylene glycol) and the tablets may also contain binders such as magnesium aluminum silicate, starch paste, gelatin, methylcellulose, sodium carboxymethylcellulose and / or polyvinylpyrrolidone ), And may optionally contain a disintegrant (e.g., starch, agar, alginic acid or a sodium salt thereof) or a boiling mixture and / or an absorbent, a colorant, a flavoring agent and a sweetening agent. The injectable composition is preferably an isotonic aqueous solution or suspension, and the composition mentioned is sterilized and / or contains adjuvants such as preservatives, stabilizers, wetting or emulsifying solution accelerators, salts for controlling osmotic pressure and / or buffering agents. They may also contain other therapeutically valuable substances.

The pharmaceutical preparations thus prepared may be administered orally or parenterally, that is, intravenously, subcutaneously, intraperitoneally, or topically, as desired. The dose may be administered in a single daily dose of 0.0001 to 100 mg / kg dividedly in several doses. The dosage level for a particular patient may vary depending on the patient's body weight, age, sex, health condition, time of administration, method of administration, excretion rate, severity of disease, and the like.

Furthermore, the present invention relates to a pharmaceutical composition comprising at least one of the above-mentioned 2,5-diaryloxazole compounds 1-5 as an active ingredient and a pharmaceutically acceptable carrier, which comprises atopic, skin inflammation such as skin pruritus A pharmaceutical composition useful for the prevention and treatment of inflammatory diseases is provided.

The inflammatory diseases defined in the present invention include inflammatory diseases such as skin inflammatory diseases including atopic dermatitis, nerve cell inflammatory diseases such as glioma cells, spondylitis, urethritis, cystitis, nephritis, pyelonephritis, vasculitis, rhinitis, sore throat, tonsillitis, acute pain or inflammatory bowel And is preferably a skin inflammatory disease, urethritis, cystitis, nephritis, pyelonephritis, rhinitis, sore throat, tonsillitis or inflammatory bowel disease.

As described above, according to the present invention, a 2,5-diaryloxazole compound can be efficiently synthesized.

Also, according to the present invention, the synthesized 2,5-diaryloxazole compounds exhibit high anti-inflammatory activity and can be used as an anti-inflammatory pharmaceutical composition applied to skin inflammation and the like.

1 is a chemical structural formula of 2,5-diaryloxazole (Compound 1-5) and derivatives thereof.
2 is a reaction formula showing the route of synthesis of 2,5-diaryloxazole compounds 1-5 by the method of the present invention. Reagents and reaction conditions are as follows. a) i) hexamethylenetetramine, ether, room temperature, overnight reaction, ii) strong hydrochloric acid, EtOH, reflux, 3h. b) CuBr ₂ , EtOAc: CHCl ₃ (1: 1), reflux, 8h. c) SOCl ₂ , anhydrous DMF, 60 ° C, 2h. d) i) Compound 8a (or Compound 8b), pyridine, room temperature, 1 h. Ii) H ₂ SO ₄ , Ac ₂ O, 90 ° C, 1 h. e) BBr ₃ (1.0 M in CH ₂ Cl ₂ ), 0 캜 - room temperature, 2-6 h. In the figure, the compound 9d is the same compound as the compound 9a, but is indicated as 9d for ease of explanation.

Hereinafter, the configuration of the present invention will be described in more detail with reference to specific embodiments. However, it is apparent to those skilled in the art that the scope of the present invention is not limited to the description of the embodiments.

Chemicals

All chemicals were used without purification as purchased unless otherwise noted. All solvents used in the reaction were distilled from the appropriate dehydrating agent under nitrogen gas. All solvents used in the chromatography were purchased and immediately used without further purification. Thin film chromatography (TLC) was carried out using a plate coated with silica gel on a DC-Plasticfolien 60, F254 (Merck, layer thickness 0.2 mm) plastic plate and observed with UV (254 nm) or with p-anisaldehyde and / And stained with phosphomolybdic acid (PMA). Chromatographic purification was performed using Kieselgel 60 (60-120 mesh, Merck). ^{The 1} H-NMR spectrum was recorded on a Varian Mercury-300 MHz FT-NMR and 75 MHz for ¹³ C, the chemical shift (δ) was expressed in parts per million (ppm) relative to TMS, the coupling constant (J) Was quoted in Hz. The peak splitting pattern was abbreviated as s (singlet), d (doublet), t (triplet), dd (doublet of doublet) and m (multiplet). CDCl ₃ / CD ₃ COCE ₃ was used as solvent and internal standard. High resolution mass spectroscopy electrospray ionization (HRMS-ESI) was recorded using an Agilent technologies 6220 TOF LC / MS spectrometer. Melting points were measured on the MEL-TEMP II apparatus and not calibrated.

2- Bromo -1- (2- Methoxyphenyl ) Ethanone  {2- Bromo -1- (2- 메틸oxyphenyl ) ethanone } (Compound 7a):

Copper (II) bromide (2.97 g, 6.66 mmol) was added to a 2-necked round bottom flask equipped with a reflux condenser, EtOAc (10.0 mL) was added, and the mixture was stirred at 70 ° C for 5 minutes. 1- (2-Methoxyphenyl) ethanone (Compound 6) (0.50 g, 3.33 mmol) was slowly added to CHCl ₃ (10.0 mL) under nitrogen atmosphere, and the mixture was refluxed for 8 hours.

After the reaction was completed, the reaction mixture was cooled to room temperature, filtered through a pad of Celite (R), and washed with EtOAc (20 mL). The filtrate was concentrated under reduced pressure. The crude product was purified by column chromatography (EtOAc: hexane = 1: 4) to give pure compound 7a (0.73 g, 96%) as a brown liquid phase. _Rf = 0.43 (EtOAc / Hexane = 1/4); ^{1 H NMR (300 MHz, CDCl} 3) δ 7.81 (1H, dd, J = 7.8, 1.8 Hz), 7.52 (1H, td, J = 7.8, 1.8 Hz), 7.05-6.96 (2H, m), 4.61 ( 2H, s), 3.94 (3H, s); ¹³ C NMR (75 MHz, CDCl ₃ )? 192.3, 158.8, 134.9, 131.6, 124.9, 121.2, 111.7, 56.0, 38.0.

Delphine  reaction ( Delepine  The general procedure of the reaction

Hexamethylenetetramine (1 mmol, 1 equivalent) was added to a stirred solution of 2-methoxyphenacyl bromide (compound 7a) / phenacyl bromide (compound 7b) (1 mmol, 1 equiv.) In diethyl ether And the mixture was stirred at room temperature for 12 hours (solid formation). The resulting solid was filtered, washed with diethyl ether (15 mL) and dried under reduced pressure to give quaternary salt, then placed in a 2-neck round bottom flask equipped with a reflux condenser and EtOH (22 mL) was added. After cooling to room temperature, the solid was filtered off, washed with EtOH (20 mL) and dried under vacuum to give the pure 2-methoxybenzoylmethylammonium chloride (compound 8a) / benzoylmethylammonium chloride (compound 8b) salt.

2-amino-1- (2 -methoxyphenyl ) ethanone Hydrochloride {2-Amino-1- (2-methoxyphenyl) ethanone hydrochloride} (Compound 8a): Yield: 88%; Brown solid; Melting point 102-104 DEG C; _{^{1 H NMR (300MHz, CDCl 3}} ) δ 7.26 (1H, d, J = 8.7 Hz), 7.11 (1H, t, J = 7.2 Hz), 4.33 (2H, q, J = 5.4 Hz), 3.94 (3H, s); ^{13 C NMR (75 MHz, CDCl} 3) δ 192.1, 159.6, 135.9, 130.0, 120.7, 112.9, 56.1, 48.7.

2-amino-1- phenylethanone Hydrochloride {2-Amino-1- phenylethanone hydrochloride} (Compound 8b): Yield: 97%; Brown solid; Melting point 180-182 DEG C; ^{1 H NMR (300 MHz, CDCl} 3) δ 8.19 (3H, br s), 7.84 (1H, d, J = 7.8 Hz), 7.67 (1H, t, J = 7.8 Hz), 7.26 (1H, d, J = 8.7 Hz), 7.11 (1H, t, J = 7.2 Hz), 4.33 (2H, q, J = 5.4 Hz), 3.94 (3H, s); ^{13 C NMR (75 MHz, CDCl} 3) δ 192.1, 159.6, 135.9, 130.0, 120.7, 112.9, 56.1, 48.7.

2,5- Diaryl oxazole  (2,5- 다 라록록azol ) General procedure of synthesis

a) To a stirred solution of the substituted benzoic acid (Compound 9a / 9b / 9c / 9d) (1.0 mmol) in anhydrous DMF (6 mL) was added dropwise thionyl chloride (3.43 mL, 2.0 mmol) And the mixture was stirred at 60 ° C for 2 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, and the solvent and an excess amount of thionyl chloride were removed under reduced pressure. The crude compound was vacuum dried for 1 hour.

b) Pyridine (4 mL) was added to 2-methoxybenzoylmethylammonium chloride (compound 8a) / benzoylmethylammonium chloride (compound 8b) salt (0.5 mmol) and stirred at ambient temperature for 10 min. To the mixture, the corresponding acid chloride was slowly added, and the mixture was stirred under a nitrogen atmosphere for 1 hour. After completion of the reaction, water (4 mL) was added, neutralized with 3N HCl, and extracted with EtOAc (2 x 20 mL). The combined organic solvent layers were washed with H ₂ O ( ₂ x 15 mL) and brine (15 mL), dried over anhydrous Na ₂ SO ₄ and concentrated in vacuo. To this crude compound was added acetic anhydride (3 mL) followed by saturated H ₂ SO ₄ (0.1 mL) at room temperature, and the mixture was stirred at 90 ° C. for 1 hour. After completion of the reaction, the reaction mixture was cooled to room temperature and H ₂ O (5 mL) was added. The mixture was saturated NaHCO ₃ Neutralized with solution and extracted with EtOAc (2 x 25 mL). The combined organic solvent layers were washed with H ₂ O ( ₂ x 15 mL) and brine (15 mL), dried over anhydrous Na ₂ SO ₄ and concentrated in vacuo. The crude compound was purified by column chromatography (EtOAc: Hexane = 1: 3) to obtain a pure oxazole compound.

2- (2,3-dimethoxy-phenyl) -5- (2-methoxyphenyl) oxazole {2- (2,3-Dimethoxyphenyl) -5- (2-methoxyphenyl) oxazole} ( Compound 1): yield : 59%; Light yellow solid; Melting point 146-148 DEG C; _Rf = 0.56 (EtOAc / hexane = 1/1); ^{1 H NMR (300 MHz, CDCl} 3) δ 7.88 (1H, dd, J = 7.8, 1.5 Hz), 7.68 (1H, s), 7.63 (1H, dd, J = 7.8, 1.5 Hz), 7.29 (1H, (1H, td, J = 8.7, 1.8 Hz), 7.14 (1H, t, J = 8.1 Hz), 7.05 (1H, td, J = 7.8, 0.9 Hz), 6.96-7.01 ), 3.98 (3H, s), 3.91 (3H, s); ^{13 C NMR (75 MHz, CDCl} 3) δ 158.3, 155.7, 153.8, 147.8, 147.7, 129.0, 127.5, 125.9, 124.4, 122.2, 121.5, 120.9, 117.4, 114.1, 110.9, 61.4, 56.2, 55.7; HRMS-ESI m / z calcd. for C ₁₈ H ₁₈ NO ₄ [M + H] &lt; ⁺ &gt;: 312.1236, found 312.1229.

2,5-bis (2-methoxyphenyl) oxazol-2,5-bis {(2-Methoxyphenyl) oxazole} (compound 10a): Yield: 61%; Light yellow solid; Melting point 110-112 DEG C; _Rf = 0.44 (EtOAc / Hexane = 1/1); ^{1 H NMR (300 MHz, CDCl} 3) δ 8.04 (1H, d, J = 7.5 Hz), 7.87 (1H, d, J = 7.5 Hz), 7.68 (1H, s), 7.42 (1H, t, J = 7.8 Hz), 7.29 (1H, t, J = 7.8 Hz), 7.08-7.03 (3H, m), 6.97 (1H, d, J = 8.1 Hz), 4.01 (3H, s), 3.97 (3H, s) ; ^{13 C NMR (75 MHz, CDCl} 3) δ 158.4, 157.6, 155.7, 147.2, 131.5, 130.1, 128.9, 127.7, 126.0, 120.9, 120.7, 117.5, 116.7, 112.1, 110.9, 56.3, 55.7; HRMS-ESI m / z calcd. _{for C 17 H 16 NO 3 [} M + H] +: 282.1130, found 282.1136.

5- (2-methoxy-phenyl) -2- (3-methoxyphenyl) oxazol-5 - {(2-Methoxyphenyl) -2- (3-methoxyphenyl) oxazole} (compound 10b): Yield: 47%; Light yellow solid; Melting point 114-116 DEG C; _Rf = 0.75 (EtOAc / Hexane = 1/1); ^{1 H NMR (300 MHz, CDCl} 3) δ 7.87 (1H, d, J = 7.5 Hz), 7.70 (1H, d, J = 7.8 Hz), 7.63 (2H, s), 7.40-7.24 (2H, m) , 7.06 (1H, t, J = 7.5 Hz), 6.98 (2H, d, J = 8.1 Hz), 3.98 (3H, s), 3.89 (3H, s); ¹³ C NMR (75 MHz, CDCl ₃ )? 160.0, 159.9, 155.8, 147.9, 130.0, 129.2, 128.9, 127.7, 125.9, 120.9, 118.9, 117.3, 116.8, 111.1, 111.0, 55.7; HRMS-ESI m / z calcd. for C ₁₇ H ₁₆ NO ₃ [M + H] &lt; ⁺ &gt;: 282.1130, found 282.1143.

2- (2,3-dimethoxyphenyl) -5-phenyl-oxazol-2- {(2,3-Dimethoxyphenyl) -5-phenyloxazole} (Compound 10c): Yield: 56%; Light yellow solid; Melting point 86-88 DEG C; _Rf = 0.48 (EtOAc / Hexane = 1/1); ^{1 H NMR (300 MHz, CDCl} 3) δ 7.71 (2H, d, J = 8.4 Hz), 7.61 (1H, dd, J = 8.1, 1.5 Hz), 7.48 (1H, s), 7.43 (1H, t, J = 7.2 Hz), 7.33 ( 1H, d, J = 7.5 Hz), 7.15 (1H, t, J = 8.1 Hz), 7.01 (1H, d, J = 8.1 Hz), 4.01 (3H, s), 3.92 (3H, s); ¹³ C NMR (75 MHz, CDCl ₃ )? 159.4, 153.9, 151.3, 147.8, 129.0, 128.5, 128.3, 124.4, 124.3, 123.4, 122.2, 121.4, 114.4, 61.5, 56.3; HRMS-ESI m / z calcd. _{for C 17 H 16 NO 3 [} M + H] +: 282.1130, found 282.1135.

2,5- Diaryl oxazole Demethylated  General Procedure

A solution of BBr ₃ (1.0 M in CH ₂ Cl ₂ , 1.0 mL, 5.00 mmol, 5.0 eq.) Was added slowly to a stirred solution of oxazole (0.2 mmol) in anhydrous CH ₂ Cl ₂ (5 mL) . The reaction was warmed to room temperature and stirred for 2-6 hours.

After completion of the reaction, MeOH (1 mL) was slowly added to quench excess BBr ₃ , stirred for 20 minutes, and then the solvent was removed under reduced pressure. H ₂ O (5 mL) and CH ₂ Cl ₂ (15 mL) were added to the crude compound and the two layers were separated. The water layer was extracted with CH ₂ Cl ₂ ( ₂ x 25 mL). Mixing the organic solvent layer is dried over anhydrous Na ₂ SO ₄ Concentrated in vacuo to obtain the title compound. [Note: a, BBr ₃ in place of 10.0 equivalent 5 equivalents for the production of compound 2 in compound 1 were used.].

3- (5- (2-hydroxyphenyl) oxazol-2-yl) benzene-1,2-diol {3- (5- (2-Hydroxyphenyl ) oxazol-2-yl) benzene-1,2- diol} (Compound 2): Yield: 95%; White solid; Melting point 174-176 DEG C; R _f = 0.32 (EtOAc / Hexane = 1/1); ^{1 H NMR (300 MHz, CD} 3 COCD 3) δ 7.92 (1H, d, J = 7.2 Hz), 7.78 (1H, s), 7.54 (1H, d, J = 7.5 Hz), 7.26 (1H, t, J = 7.2 Hz), 6.99-7.01 (3H, m), 6.90 (1H, t, J = 7.8 Hz); ¹³ C NMR (75 MHz, CD ₃ COCD ₃ )? 160.5, 154.6, 148.0, 146.7, 146.2, 130.3, 126.4, 125.2, 120.8, 120.5, 118.5, 117.0, 116.6, 115.5, 111.8; HRMS-ESI m / z calcd. _{for C 15 H 12 NO 4 [} M + H] +: 270.0766, found 270.0760.

2,2 '- (2,5-oxazol-yl) dimethyl phenol {2,2' - (Oxazole-2,5-diyl) diphenol} (compound 3): Yield: 91%; White solid; Melting point 184-186 DEG C; R _f = 0.30 (EtOAc / Hexane = 1/1); ^{1 H NMR (300 MHz, CD} 3 COCD 3) δ 11.21 (1H, s), 9.59 (1H, s), 8.04 (1H, d, J = 8.2 Hz), 7.93 (1H, d, J = 7.8 Hz) , 7.77 (1H, s), 7.38 (1H, t, J = 7.8 Hz), 7.25 (1H, t, J = 7.5 Hz), 7.08-7.00 (4H, m); ¹³ C NMR (75 MHz, CD ₃ COCD ₃ )? 160.2, 158.1, 154.6, 148.1, 133.0, 130.4, 126.7, 126.5, 125.3, 120.8, 120.3, 117.6, 116.6, 115.5, 111.7; HRMS-ESI m / z calcd. for C ₁₅ H ₁₂ NO ₃ [M + H] &lt; ⁺ &gt;: 254.0817, found 254.0806.

2- (2- (3-hydroxyphenyl) oxazol-5-yl) phenol {2- (2- (3-Hydroxyphenyl ) oxazol-5-yl) phenol} ( compound 4): Yield: 98%; White solid; Melting point 240-242 ° C; _Rf = 0.33 (EtOAc / Hexane = 1/1); ^{1 H NMR (300 MHz, CD} 3 COCD 3) δ 9.44 (1H, br s), 8.77 (1H, br s), 7.87 (1H, d, J = 8.1 Hz), 7.67 (2H, s), 7.63 ( 1H, d, J = 7.5 Hz), 7.36 (1H, t, J = 8.1 Hz), 7.21 (1H, t, J = 7.8 Hz), 6.97-7.06 (3H, m); ¹³ C NMR (75 MHz, CD ₃ COCD ₃ )? 160.2, 158.5, 154.5, 148.9, 130.9, 129.8, 129.7, 127.9, 126.3, 120.8, 118.1, 116.6, 116.2, 113.5; HRMS-ESI m / z calcd. for C ₁₅ H ₁₂ NO ₃ [M + H] &lt; ⁺ &gt;: 254.0817, found 254.0823.

3- (5-phenyl-oxazol-2-yl) benzene-1,2-diol {3- (5- Phenyloxazol -2-yl ) benzene-1,2-diol} ( Compound 5): Yield: 88% ; White solid; Melting point 134-136 DEG C; _Rf = 0.25 (EtOAc / Hexane = 1/1); ^{1 H NMR (300 MHz, CD} 3 COCD 3) δ 11.20 (1, s), 8.02 (1H, s), 7.87 (2H, dd, J = 6.9, 1.5 Hz), 7.79 (1H, s), 7.52- 7.48 (3H, m), 7.42 (1H, dd, J = 6.9, 1.5 Hz), 7.00 (1H, dd, J = 7.8, 1.2 Hz), 6.90 (1H, td, J = 7.8, 1.2 Hz); ¹³ C NMR (75 MHz, CD ₃ COCD ₃ )? 161.7, 151.0, 146.7, 146.3, 129.8, 129.6, 128.1, 125.0, 122.2, 120.5, 118.7, 117.1, 111.7; HRMS-ESI m / z calcd. for C ₁₅ H ₁₂ NO ₃ [M + H] &lt; ⁺ &gt;: 254.0817, found 254.0810.

Nitric oxide (NO) production inhibition

The NO production inhibitory effect of the resulting oxazole compounds 1-5 was analyzed by measuring the amount of NO (NO) in RAW 264.7 cells stimulated with lipopolysaccharide (LPS) as an indicator of anti-inflammatory activity. Indeed, the quantification of nitric oxide is inherently difficult due to the presence of other scavenging molecules and the persistent non-existent nature of the nitric oxide. Therefore, NO levels were indirectly assessed by analyzing the nitrite (NO ₂ -) concentration, which is a stable oxidation product in the culture supernatant, using an acidic grease reagent. L-NMMA ( N ^G -Monomethyl-L-arginine acetate) was used as a positive control (18).

The anti-inflammatory effects of compounds 1-5 on the production of NO by induced macrophages are shown in Table 1. When LPS-treated cells were treated with the oxazole compounds synthesized in the present invention at a concentration of 1 to 10 μM, NO production was inhibited in a concentration-dependent manner. As shown in Table 1, the highest inhibition rate was observed at the highest concentration (10 μM). Compared with the positive control L-NMMA (79.3%), Compound 3 showed the highest inhibition rate of 70.7% at 10 μM, Compound 5 showed 68.3% and Compound 2 showed 53.9%. However, the trimethoxy derivatives (Compound 1) and Compound 4 of Compound 2 had almost no inhibitory effect. From the structure-activity results, the C2-aryl group of oxazole containing a hydroxyl group (-OH) at position 2 appears to play an essential role in the inhibitory activity. Next, cell viability was analyzed by MTT cell viability assay to confirm that apoptosis was not due to a decrease in NO expression. As a result, no cytotoxicity was observed at the highest concentration of 10 μM in RAW 264.7 cells. The IC ₅₀ values of compounds 1-5 were evaluated using GraphPad Prism 4.0 software and were> 100, 6.31, 2.33, 24.83 and 2.30 μM, respectively (Table 1). From these pharmacological results, Compound 3 strongly suppresses the production of NO induced by LPS and does not show significant cytotoxicity, so it can be considered as a possible NO production inhibitor candidate.

conclusion

The present inventors have invented a method for efficiently synthesizing a 2,5-diaryloxazole compound (1-5) having a total yield of 38-48% from a commercially available starting material. This synthesis led to the Delpine and Robinson-Gabriel reactions. The present inventors evaluated oxazole compounds synthesized in the present invention by evaluating the inhibitory effect of LPS-induced NO production in RAW 264.7 cells and found that the oxazole compounds of the present invention inhibit NO production remarkably in a concentration-dependent manner. In the present invention, Compound 3 (70.7%; IC ₅₀ = 2.33 [mu] M) exhibited more potent NO production inhibitory activity than the positive control L-NMMA (79.3%; IC ₅₀ = 4.51 μM). Compound 5 (68.3%; IC ₅₀ = 2.30 μM) and Compound 2 (53.9%; IC ₅₀ = 6.31 [mu] M) showed inhibitory activity. The compound 3 of the present invention is considered to be a potential compound as an anti-inflammatory agent targeting NO production.

Claims (7)

(A) Hexamethylenetetramine was added to compound 7a or 7a of phenacyl bromide (compound 7b) represented by the general formula (7) and reacted at room temperature overnight to obtain a quaternary ammonium salt to give a quaternary ammonium salt, Methoxybenzoylmethylammonium chloride (Compound 8a) represented by Chemical Formula 8 was reacted with Compound 7b to obtain benzoylmethylammonium chloride (Compound 8b) represented by Chemical Formula 8 from compound 7b, and acid hydrolysis reaction was carried out with refluxing with hydrochloric acid and ethanol, ; And
(B) Substituted benzoyl chloride produced from the benzoic acid compounds 9a-9c represented by the general formulas (9a), (9b) and (9c) is reacted with the compound 8a or 8b in the presence of pyridine, and the Robinson-Gabriel dehydration cyclodehydration is carried out to obtain the compound 9a To obtain 2,5-diaryloxazole represented by the general formula (1) or 2,5-diaryloxazole represented by the general formulas (10a), (10b) and (10c) from the benzoic acid compound represented by the general formula , A method for synthesizing a 5-diaryloxazole compound.
&Lt; Formula 1 >

&Lt; Formula 7 >

(8)

<Formula 9a>

<Formula 9b>

<Formula 9c>

<Formula 10a>

&Lt; Formula 10b >

&Lt; Formula 10c >

The method according to claim 1,
After step (b)
(C) A solution of BBr ₃ is added to 2,5-diaryloxazole represented by the above formula (1) or (10a), (10b) or (10c) to give 2,5-diaryloxazole -5. &Lt; / RTI >
(2)

(3)

&Lt; Formula 4 >

&Lt; Formula 5 >

The method according to claim 1,
Wherein said compound 7a is obtained by? -Brominating 2'-methoxyacetophenone using CuBr ₂ .
The method according to claim 1,
Wherein the phenacyl bromide is obtained by deprotecting a methoxy group in the compound 7a.
The method according to claim 1,
Wherein the Robinson-Gabriel dehydration ring closure reaction is carried out by adding H ₂ SO ₄ and Ac ₂ O to the 2,5-diaryl oxazole compound.


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