Technical background

COX-1 isoenzyme plays a significant role in a variety of diseases, as it catalyzes the bioprocesses behind many health problems. The belief that cyclooxygenase-1 (COX- 1) inhibition is the root of side effects associated with traditional nonsteroidal antiinflammatory drugs (tNSAIDs) has been abandoned over the last decade, and indeed, the COX-1 isoenzyme has been receiving increased attention as a pharmacotherapeutic target because of its involvement in many health problems. With better knowledge about the extent of COX-1 expression in many cells and tissues, it has been possible to gain significant insight into its role in atherosclerosis, endothelial dysfunction, neuro-inflammation, inflammatory syndrome, pain and pain processing, pre-term labor, a number of types of cancer, and gastrointestinal toxicity. Prostaglandins (PGs), as main products of the arachidonic acid bio-conversion catalyzed by COXs (COX-1 and COX-2), are thought to be determinants in the protection of gastric mucosa, and COX-1 expression levels in the GI tract are much higher than those of the other cyclooxygenase isoform, COX-2. Stomach irritation is one of the major side effects of NSAIDs, and it is thought to be caused by the inhibition of COX-1. However, various experiments have suggested that COX-1 deficiency or inhibition is compatible with normal small intestine integrity, without evidence of COX-1 -selective inhibition being the cause of gastric damage. Therefore, highly selective COX-1 inhibitors could be useful pharmacological tools for shedding light on the role of COX-1 in the damage of gastric tissues. The development of selective COX-1 inhibitors could be quite relevant for the treatment of diseases in which the COX-1 isoform is negatively overexpressed. Very few selective COX-1 inhibitors are currently known.

The inventors have been publishing the results of an investigation aimed to identify the molecular determinants that switch the inhibitory activity toward the COX-1 isoenzyme and away from COX-2. These data were partly reported in Chem. Med. Chem. 2012, 7, 629 - 641, firstly published on the web on January 25, 2012 (and incorporated herein as reference).

It was surprisingly found out that among a number of compounds which were synthesized and tested, only compound 5-(furan-2-yl)-l-(4-methoxyphenyl)-3- (trifluoromethyl)-lH-pyrazole (I) was found to be particularly active in the selective inhibition of COX-1 [COX-1 IC ₅₀ = 3.4 mM; COX-2 IC ₅₀ > 100 mM]. After said publication, two further compounds were prepared, i.e. the hydroxyl derivative of compound (I), herein after referred to as compound (II).

According to a first aspect, the present invention relates to compounds ¹² C-(I), (II), ⁿ -(I) and their salts.

¹² C-(I) (II) ¹¹ C-(I)

The salts of the compounds of formula ¹² C-(I) and ⁿ C-(I) may be pharmaceutically acceptable salts, in case they are used in pharmaceutically acceptable compositions. However, the salts of compounds of formula ¹² C-(I) and ⁿ C-(I) may also be non- pharmaceutically acceptable, in case they should be used for chemical purposes, or as a tool for "in vivo" tests to study the physiopathological role of COXs.

According to an embodiment of the invention, the compound of formula ¹² C-(I), ^U C- (I) and their salts thereof is new and is a potent and selective inhibitor of COX-1 and can be used for preventing and treating any pathology wherein the inhibition of COX-1 is beneficial.

So, according to another of its aspect, the present invention relates to a method for selectively inhibiting COX-1 which comprises administering to a mammal in need thereof an effective amount of the compounds of formula ¹ C-(I) and ⁿ C-(I) or pharmaceutically acceptable salts thereof.

As a preferred embodiment, the invention relates to a method for preventing and/or treating a COX-1 -related pathologies which comprise administering to a mammal in need thereof an effective amount of the compounds of formula ¹² C-(I) and ⁿ C-(I) or pharmaceutically acceptable salts thereof.

As another preferred embodiment, the invention relates to a method for preventing and/or treating a pathology selected from cancer, neuro-inflammation, inflammatory syndrome, cardioprotection, fever and pain which comprises administering to a mammal in need thereof an effective amount of the compounds of formula ¹² C-(I) and ⁿ C-(I) or pharmaceutically acceptable salts thereof.

1 1 1

The use of the compounds C-(I) and C-(I) or pharmaceutically acceptable salts thereof for the treatments of the above pathologies is another aspect of the invention. Compounds of formula ¹² C-(I) and ⁿ C-(I) may be prepared according to the reaction details given in the experimental section of this application.

The biological assays were carried out as disclosed in Chem. Med. Chem. 2012, 7, 629 - 641.

According to another of its aspects, the present invention relates to radiolabeled compounds of formula (I) or one of its salts wherein one or more of the atoms is a C carbon atom and/or a F atom as a radionuclide.

According to a preferred embodiment, the ^U C carbon atom in the compound of formula ^U C-(I) is the carbon atom of the methoxy group.

The C and/or F radiolabeled isotopic derivatives are especially useful in diagnostics, namely in Positron Emission Tomography (PET) diagnostic method.

Recent reports have shown that the expression of COX-1 is an early event of several human pathologies including neuro-inflammation, inflammatory syndrome, neurodegenerative diseases, atherosclerosis, endothelial dysfunction preterm labor, pain, and carcinogenesis. In particular, COX-1 is overexpressed in various stages and progression of human epithelial ovarian cancers, where it controls the production of prostaglandins and promotes angiogenic growth factor production. A significantly reduction of tumor growth was found in an in vivo model with ovarian surface epithelial cells allografted in female nude mice, after treatment with SC-560, a highly selective COX-1 inhibitor. COX-1 is an ideal target, as a novel biomarker, for the diagnosis by imaging and the treatment of epithelial ovarian cancer in humans. Unfortunately, treatment of this neoplastic diseases is still limited because of the lack of a non-invasive and effective imaging agent for early diagnosis. So, development of a COX- 1 -targeted Positron Emission Tomography (PET) radiotracer is a matter of the extreme importance.

Accordingly, the present invention also relates to a diagnostic method for the detection and the examination of neuro-inflammation and cancer, especially ovarian cancer, which comprises the administration of a ⁿ C and/or ¹⁸ F radiolabeled compound of formula (I) or of one of their salts to the mammal to be examined. According to a preferred embodiment, the ^u C-radiolabeled compound is that of formula ^U C-(I) bearing the ¹¹ C carbon atom in the methoxy group.

Said compound may be prepared according to any conventional method, for instance by replacing the group containing the ¹² C carbon atom of the compound of formula

19 1 1

C-(I) with a C carbon atom as a radionuclide. An illustrative, detailed reaction is reported in the experimental section of this application.

According to the present invention, the mammal is preferably a human being.

According to another of its aspects, the invention relates to a pharmaceutical or a diagnostic composition comprising the compound of formula ⁿ C-(I), a radiolabeled compounds thereof or a pharmaceutically acceptable salts thereof.

According to another of its aspect, the invention relates to a process for the preparation of compound of formula ¹² C-(I) and the radiolabeled compound ^U C-(I), thereof or a pharmaceutically acceptable salt thereof, as disclosed in the experimental section of the application.

According to another of its aspects, the invention relates to the process of demethylation and re-methylation of a mofezolac precursor (III), as well as its conversion into compounds (IV), ^U C-(III), (V) and (VI) (Figure 2, Scheme 1). Both the mofezolac (VII) (Scheme 2) and its precursor (III) are COX-1 selective inhibitors (COX-1 IC50 values are 29 and 76 nM, respectively).

The re-methylation reaction is accomplished to mimic the incorporation into the mofezolac precursor ¹² C-(III), of the radio-isotope ⁿ C to obtain ^U C-(III), able to emit positrons. The methyl bonded to the isoxazole C ₅ of mofezolac precursor (III) was brominated to compound (V), and the bromide replaced with ¹⁹ F [compound (VI), step d, Scheme 1] to mimic the incorporation of the radio-isotope ¹⁸ F, a positron emitter.

(V) (VI)

Scheme 1. Reagents and conditions: a) BBr ₃ , CH ₂ C1 ₂ , -78 °C, 2h; b) NaH, DMF, r.t., 10 min., CH ₃ I; c) NBS, AIBN, CC1 ₄ ; d) 1M TBAF in THF.

Also the mofezolac was demethylated and re-methylated to mimic the incorporation of the radio-isotope ^U C, able to emit positrons. According to this aspect, the invention relates to compounds of formula (IX) and (XII) and their salts:

According to this aspect, the invention relates to a process for the preparation of compound of formula ^{11 12} C-(IX) and compound (XII), thereof or a pharmaceutically acceptable salt thereof, as disclosed in the experimental section of the application. According to another of its aspects, the invention relates to a pharmaceutical or a diagnostic composition comprising the compound of formula ^U C-(IX), a radiolabeled compounds thereof or a pharmaceutically acceptable salts thereof. Accordingly, the present invention also relates to a diagnostic method for the detection and the examination of neuro-inflammation and cancer, especially ovarian cancer, which comprises the administration of a ¹¹ C radiolabeled compound of formula (IX) or of one of its salts to the mammal to be examined.

As another preferred embodiment, the invention relates to a method for preventing and/or treating a pathology selected from cancer, neuro-inflammation, inflammatory syndrome, cardioprotection, fever and pain which comprises administering to a mammal in need thereof an effective amount of the compounds of formula ^11/12 C- (IX) and (XII) or pharmaceutically acceptable salts thereof.

Besides, the mofezolac carboxylic acid moiety was reduced to alcohol, that in turn was activate as tosylate(Ts)-compound (XI) and by treatment with Bu ₄ NF afforded the vinylisoxazole (XII).

In particular compounds were prepared as depicted in the following Scheme 2:

Scheme 2. Reagents and conditions: a) 48% HBr, AcOH; b) NaH, DMF, r.t, 10 min.; CH ₃ I; c) 1M BMS in THF, 0°C; d) (TsO) ₂ , CH ₂ C1 ₂ , 0°C; e) 1M TBAF in THF. According to another of its aspect, the invention relates to compounds of formula (XIII), (XIV) and their salts

(XIII) (XIV)

In particular, the 3-(5-chlorofuran-2-yl)-4-phenylisoxazol-5-amine (XIII) was found to be highly potent and selective COX-1 inhibitor (IC ₅₀ = 1.1 μΜ). It was prepared by 1,3-dipolar cycloaddition with 40% yield by a one pot procedure, from 5- chlorofuran-2-carbonitrile oxide and lithiated phenylacetonitrile as dipolarophile (Scheme 3).

Scheme 3. Reagents and conditions: a) LDA or t-BuLi, -78°C, 2h;, b) 5-chlorofuran- 2-carbonitrile oxide; c) sat. aq. NH ₄ C1.

The 3-(5-chlorofuran-2-yl)-4-(4-aminophenyl)-5-methylisoxazole (XIV) (COX-1 IC5o = 4.3 μΜ) was prepared, to verify the influence on COX-1 activity of the amine group on phenyl at isoxazole-C4 (XIII), starting from the inactive 3-(5-chlorofuran- 2-yl)-4-(4-nitrophenyl)-5-methylisoxazole (XV):

(XV) (XIV)

Scheme: Reagents and conditions: a) SnCl ₂ /HCl, reflux, 4h. Compounds selected from compounds of formula (I), (II), (V), (VI), (IX), (XII), (XIII) and (XIV) and their salts, especially their pharmaceutically acceptable salts, are novel compounds and represent a subject-matter of the invention, as well their use for preventing and/or treating a COX- 1 -related pathology and for preventing and/or treating a pathology selected from cancer, neuro-inflammation, inflammatory syndrome, cardioprotection, fever and pain.

According to another of its aspects, the invention relates to a pharmaceutical or a diagnostic composition comprising the compounds of formula (I), (II), (V), (VI), (IX), (XII), (ΧΠΙ) and (XIV) or their pharmaceutically acceptable salts or radiolabeled compounds thereof or pharmaceutically acceptable salts thereof.

Radiolabeled derivatives of the compounds of formula (I), (II), (V), (VI), (IX), (XII), (XIII) and (XIV) and their salts, especially their pharmaceutically acceptable salts are novel compounds and represent a subject-matter of the invention, as well their use in radiomethabolic therapy and cancer, especially ovarian cancer and neuroinflammation diagnosis. Particularly preferred compounds are selected from those of formula 11 C-(I), l lC-(III), 18F-(VI), l lC-(IX) and their salts.

The processes disclosed in this application for preparing the above compounds are also a subject-matter of the invention.

The experimental section of the application illustrates the invention in a non-limiting way.

Experimental Section

Example 1

5-(Furan-2-yl)-l-(4-methoxyphenyl)-3-(trifluoromethyl)-lH-py razole (I):

4-Methoxyphenylhydrazine (0.669 gr, 4.85 mmol) was added dropwise to 4,4,4- trifluoro-l-(furan-2-yl)butane-l,3-dione (1 g, 4.85 mmol) and A1 ₂ 0 ₃ (1.484 g, 14.55 mmol). The heterogeneous reaction mixture was stirred at room temperature for 28 h. CH ₂ C1 ₂ was then added, the suspension was filtered over silica gel, and the solvent was removed under reduced pressure. Column chromatography (silica gel, PE/EtOAc 7:3) of the reaction crude afforded 5-(furan-2-yl)-l-(4-methoxyphenyl)-3- (trifluoromethyl)-7H-pyrazole (I) (530 mg, 36% yield) as an orange solid; mp: 71.0- 73.0 °C); 1H NMR (400 MHz, CDC1 ₃ ): 5=7.43-7.42 (m, 1H, furyl proton), 7.37-7.34 (m, 2H, aromatic protons), 7.00-6.98 (m, 2H, aromatic protons), 6.89 (s, 1H, pyrazole proton), 6.34-6.32 (m, 1H, furyl proton), 5.91-5.89 (m, 1H, furyl proton), 3.88 ppm (s, 3H, OMe); ^l9 F NMR (376 MHz, CDC1 ₃ ): δ=-66.5 ppm; ¹³ C NMR (100 MHz, CDC1 ₃ , δ): 175.0, 160.5, 143.6 (m), 143.3, 136.6, 132.6, 127.7, 127.3, 121.3 (q, 2920, 2849, 1609, 1505, 1461, 1431, 1386, 1301, 1245, 1214, 1 178, 1 155, 1125, 1022, 973, 832, 801, 744 cm ; GC-MS (70 eV) m/z (rel. int): 308 (100), 293 (10), 265 1, 254 (5), 237 (4), 217 (4), 196 (3), 185 (4), 168 (3), 115 (2), 103 (2), 90 (3), 77 (7), 64 (7), 51 (3); Anal, calcd for C15H11F3N2Q2: C 58.45, H 3.60, N 9.09, found: C 58.43, H 3.65, N 9.10.

Example 2

The compounds may be prepared according to the following scheme:

4-[3-(Trifluoromethyl)-5-(furan-2-yl)-iH-pyrazol-l-yl]phe nol (II). 1 mL of

Boron tribromide solution 1.0 M in methylene chloride was added to a solution of 5- (Furan-2-yl)- 1 -(4-methoxyphenyl)-3 -(trifluoromethyl)-iH-pyrazole (I) ( 1 OOmg, 0.32mmol) in CH2CI2 dry (5 mL) at -50°C. The reaction mixture was stirred at room temperature for 18h; NaHC0 ₃ was then added, and after separation of the two phases, the organic layer was dried over Na ₂ S0 ₄ and the solvent was removed under reduced pressure. Column chromatography (silica gel, PE/EtOAc 8:2) of the reaction crude afforded 4-[3-(trifluoromethyl)-5-(furan-2-yl)-7H-pyrazol-l-yl]phenol (II) (90 mg, 96% yield). Ή NMR (300 MHz, CDCI3): 6=7.53-7.52 (m, 1H, furyl proton), 7.24-7.20 (m, 2H, aromatic protons), 6.95-6.90 (m, 3H, 2H aromatic protons and IH pyrazole proton), 6.38-6.37 (m, IH, furyl proton), 5.94-5.92 (m, IH, furyl proton); ¹³ C NMR (100 MHz, CDC1 ₃ ): 6=156.1 , 140.6, 140.3, 139.6 (q, ² J _C -F= 38 Hz), 134.2, 128.1, 124.7, 1 18.5 (q, _-Ρ =268 Hz), 112.8 (m), 108.3, 106.8 (m), 99.5 (m) ppm; ¹⁹ F NMR (376 MHz, CDC1 ₃ ): δ= -62.8 ppm; FT IR (KBr): v=3169, 2925, 2853, 1612, 1594, 1524, 1507, 1446, 1434, 1385, 1290, 1247, 1221, 1177, 1157, 1142, 1 104, 1030, 997, 976, 839, 805, 748 cm-1 ; GC-MS (70 eV) m/z (rel. int): 294 (100), 275 (8), 265 (14), 248 (6), 240 (8), 217 (2), 197 (6), 171 (6), 115 (3), 90 (1), 77 (2), 65 (10), 52 (3).

5-(Furan-2-yl)-l - [4-(* ¹ C)methoxyphenyI] -3-(trifluoromethyl)-2H-pyrazole [ ^U C- (I)]. NaH (180 mg; 7.5 mmol) was added to a solution of 4-[3-(trifluoromethyl)-5-

(furan-2-yl)-7H-pyrazol-l-yl]phenol (II) (30 mg; 0.10 mmol) in 5 mL of DMF dry.

The mixture was stirred for 10 minutes and then ⁿ CH ₃ I (0.1 mL, 1.6 mmol) was added. The reaction mixture was then kept under reflux for 1 h. After cooling, EtOAc was added, and the mixture was washed for three times with brine, and after separation of the two phases, the organic layer was dried over Na ₂ S0 ₄ , and the solvent was removed under reduced pressure. The reaction afforded an orange solid

(32 mg, 98% yield).

Preparation of 3,4-bis(4-hydroxyphenyl)-5-methylisoxazole (IV)

To a solution of (III), [3,4-bis(4-methoxyphenyl)-5-methylisoxazole] (100 mg, 0.34 mmol) in CH ₂ C1 ₂ (5 mL) kept at -78 °C by a bath of dry ice/acetone, 1M BBr ₃ in CH ₂ C1 ₂ was added dropwise (1 mL, 1 mmol). The reaction mixture was stirred for 2 h, allowing the temperature to reach r.t., Then, NaHC0 ₃ sat. aq. solution was added to the reaction mixture. The aqueous solution was extracted with CH ₂ C1 ₂ , the organic layer was dried over anhydrous Na ₂ S0 ₄ and the solvent removed under reduced pressure. The product 2 was isolated as a white solid (45% yield) by chromatography on silica gel (hexane/ethyl acetate = 6:4) of the reaction crude. Its structure was confirmed by 1H NMR (DMSO-i¾ δ: 2.40 (3H, s), 6.75 (2H, d, J= 8.8 Hz, ArH), 6.79 (2H, d, J= 8.8 Hz, ArH), 7.01 (2H, d, J= 8.8 Hz, ArH), 7.21 (2H, d, J= 8.8 Hz, ArH), 9.64 (IH, br s, OH: exchanges with D ₂ 0), 9.79 (IH, br s, OH: exchanges with D ₂ 0).

Preparation of 3,4-bis(4-methoxyphenyl)-5-methylisoxazole ⁿ C-(III) To a solution of NaH (9.8 mg, 0.41mmol) in DMF (0.3mL) the compound 2 (50 mg, 0,19mmol) in DMF (0,4mL) was added dropwise. The mixture was stirred for 10 minutes at r.t. and then CH ₃ I (0.1 mL, 1.5 mmol) was added, to give a pale orange homogeneous solution that was stirred for a further lh. The reaction crude was extracted with ethyl acetate three times and washed with brine three times, to remove DMF. The organic layer was dried over anhydrous Na ₂ S0 ₄ and the solvent removed under reduced pressure to give the white product (50% yield), which structure was confirmed by 1H-NMR (CDC1 ₃ ) δ: 2.40 (3H, s), 3.83 (3H, s), 3.80 (3H, s) 6.83 (2H, d, J=9.0), 6.90 (2H, d, J=9.0 Hz) 7.09 (2H, d, J=9.0 Hz), 7.37 (2H, d, J=9.0 Hz). Mp: 95-98°C.

Preparation of 5-bromomethyl-3,4-bis(4-methoxyphenyI)-isoxazole (V)

To a solution of (III) (500 mg, 1.7 mmol) in CC1 ₄ (8.75 mL) kept at r.t., NBS (362 mg, 2.05 mmol) and AIBN (140 mg, 0.85mmol) were added. The mixture was stirred overnight at r.t. to activate the substrate, giving a pale yellow homogeneous solution. After 16 h, the same amount of NBS and AIBN were added. The reaction mixture was refluxed for 2 hours, and then stopped by adding distilled water. The aqueous solution was extracted with CH ₂ C1 ₂ . The organic layer was dried over anhydrous Na ₂ S0 ₄ and the solvent removed under reduced pressure. The product (V) was isolated as a yellow solid (55% yield) by flash chromatography on silica gel (hexane/ethyl acetate 9: 1) of the reaction crude, which chemical structure was assigned by 1H NMR (400 MHZ, CDC1 ₃ , δ): 3.80 (s, 3H, CH ₃ ), 3.84 (s, 3H, CH ₃ ); 4.44 (s, 2H, CH ₂ ), 6.83 (d, 2H, J= 9.0 Hz, ArH), 6.93 (d, 2H, J= 9.0 Hz, ArH), 7.20 (d, 2H, J= 9.0 Hz, ArH); 7.38 (d, 2H, J= 9.0 Hz, ArH) and ESI-MS: m/z (%): C ₁₇ H ₁₇ BrN0 ₃ (M) ⁺ , 373.

Preparation of 5-fiuromethyl-3,4-bis(4-methoxyphenyl)-isoxazole (VI)

To 5-bromomethyl-3,4-bis(4-methoxyphenyl)-isoxazole (V) (50 mg, 0.134 mmol) at room temperature TBAF 1M in THF (402 μΐ) was added dropwise, and the mixture was stirred for 24 h at room temperature to give a pale red homogeneous solution. The reaction was stopped by addition of distilled water and the aqueous solution was extracted with ethyl acetate. The organic layer was dried over anhydrous Na ₂ S0 ₄ and the solvent removed under reduced pressure. The product (VI) was isolated as a yellow solid (45% yield) by column chromatography on silica gel (hexane/ethyl acetate 8:2) of the reaction crude, which the chemical structure was assigned by 1H NMR (400 MHZ, CDC1 ₃ , δ): 3.81 (s, 3H, CH ₃ ), 3.84 (s, 3H, CH ₃ ); 5.33 (d, 2H, J _H-F =48.4 Hz), 6.86 (d, 2H, J= 9.0 Hz ArH), 6.93 (d, 2H, J= 9.0 Hz, ArH), 7.17- (d, 2H, J= 9,0 Hz, ArH); 7.41 (d, 2H, J= 9.0 Hz, ArH) and ESI-MS: m/z (%): (M) ⁺ , 313. Preparation of 2- [3,4-bis(4-hydroxyphenyl)isoxazol-5-yl] acetic acid (VIII)

A mixture of mofezolac 6 (2.5 g, 7.4 mmol) and 47% HBr (10 mL) in AcOH (10 mL) was heated under reflux for 5h. Then, water was added and the product extracted with ethyl acetate. The organic layer was washed with water, dried over MgS0 ₄ and solvent removed under reduced pressure. Recrystallizion of the reaction crude gave 9 (0.8 g, 35%). Mp 183-185 °C (CH ₃ CN, dec, with foaming). IR: (KBr): 1720 (C=0) cm ^"1 . ^l H NMR (DMSO-i¾ δ: 3.75 (2H, s, CH ₂ ), 6.75 ( 2H, d, J=8.8 Hz, ArH), 6.79 (2H, d, J=8.8 Hz, ArH), 7.01 (2H, d, J=8.8 Hz, ArH), 7.21 (2H, d, J=8.8 Hz, ArH), 9.64 (IH, br s, OH: exchanges with D ₂ 0), 9.79 (IH, br s, OH: exchanges with D ₂ 0), 12.89 (IH, br s, COOH: exchanges with D ₂ 0). ¹³ C-NMR (75 MHz, CD ₃ OD) δ: 31.3, 115.2, 115.5, 117.6, 119.9, 120.4, 157.6, 159.0, 161.3, 162.9, 170.4. Anal.Calcd for C ₁₇ H ₁₃ N0 ₅ : C, 65.16; H, 4.40; N, 6.33. Found: C, 65.45; H, 4.38; N, 6.44.

Preparation of methyl 2-[3,4-bis(4-methoxyphenyl)isoxazol-5-yl]- dimethylacetate (IX)

To a solution of NaH (9.8 mg, 0.6 mmol) in DMF (0.3 mL) (VIII) (50 mg, 0,19 mmol) in DMF (0.4mL) was added dropwise. The reaction mixture was stirred for 10 minutes and then CH ₃ I (1.5 mmol) was added and stirred for further lh to give a pale orange homogeneous solution. The crude reaction was extracted with ethyl acetate three times, and washed with brine three times to remove mostly DMF. The organic layer was dried over anhydrous Na ₂ S0 ₄ and the solvent removed under reduced pressure. Chromatographic column of the reaction crude, afforded a white product (IX) (50% yield). 1H NMR (CDC1 ₃ ) δ: 1.55 (6H, s), (3.44 (3H, s), 3.76 (3H, s), 3.82 (3H, s), 6.77 (2H, d, J= 9.0 Hz, ArH), 6.87 (2H, d, J= 9.0 Hz, ArH), 7.04 (2H, d, J= 9.0 Hz, ArH), 7.30 (2H, d, J= 9.0 Hz, ArH).

Preparation of 3,4-bis(4-methoxyphenyl)-5-hydroxyethylisoxazole (X) To a solution of mofezolac (VII) (200 mg, 0.589 mmol), in anhydrous THF (2 mL) kept at 0 °C by a bath of ice, 1M BMS in THF (1.16 mL, 1.16 mmol) was added dropwise, and the mixture was stirred overnight at room temperature to give a pale yellow homogeneous solution. Distilled water (1 mL), 20% NaOH (I mL) and 35% H ₂ 0 ₂ (1 mL) were added and the obtained reaction mixture was stirred for 1 hour. Then, the solution was extracted with ethyl acetate. The organic layer was dried over anhydrous Na ₂ S0 ₄ and the solvent removed under reduced pressure. The product (X) was isolated as a white solid (68% yield) by flash chromatography on silica gel (hexane/ethyl acetate 6:4) of the reaction crude, the Ή NMR (400 MHZ, CDC1 ₃ , δ): 3.81 (s, 3H, CH ₃ ), 3.85 (s, 3H, CH ₃ ); 4.44 (t, 2H, J- 6.6 Hz CH ₂ ), 4.26 (t, 2H, J= 6.6 Hz CH ₂ 6.85 (d, 2H, J= 9.0 Hz, ArH), 6.95 (d, 2H, J= 9.0 Hz, ArH), 7.21 (d, 2H, J= 9.0 Hz, ArH); 7.39 (d, 2H, J= 9.0 Hz, ArH). ESI-MS: m/z (%): C ₁₈ H ₂₀ NO ₄ (M) ⁺ , 325. Preparation of 2- [3,4-bis(4-methoxypheny l)isoxazol-5-yl] ethyl-4- methylbenzenesulfonate (XI)

To a solution of (X) (3,4-bis(4-methoxyphenyl)-5-hydroxyethylisoxazole) (160 mg, 0.492 mmol), in CH ₂ C1 ₂ (11.4 mL) kept at 0 °C by a bath ice, /?-toluensulphonic anhydride (544 mg, 1.67 mmol) and triethylamine (466 μΐ) were added. The reaction mixture was stirred overnight at r.t. to give a pale yellow homogeneous solution. Then, water was added to the reaction mixture and the aqueous solution was extracted with CH ₂ C1 ₂ . The organic layer was dried over anhydrous Na ₂ S0 ₄ and the solvent removed under reduced pressure. The product (XI) was isolated as a yellow solid (60% yield) by flash chromatography on silica gel (hexane/ethyl acetate 7:3) of the reaction crude. 1H NMR (400 MHZ, CDC1 ₃ , δ): 2.36 (s, 3H, CH ₃ ), 3.05 (t, 2H, J= 6.6 Hz CH ₂ ); 3.78 (s, 3H, CH ₃ ), 3.82 (s, 3H, CH ₃ ), 4.30 (t, 2H, J= 6.6 Hz CH ₂ 6.82 (d, 2H, J= 9.0 Hz, ArH), 6.88 (d, 2H, J= 9.0 Hz, ArH), 7.03 (d, 2H, J= 9.0 Hz, ArH); 7.30 (d, 2H, J= 9.0 Hz, ArH), 7.33 (d, 2H, J= 9.0 Hz, ArH), 7.69 (d, 2H, J= 9.0 Hz, ArH). ESI-MS: m/z (%): C ₂₅ H ₂₅ SN0 ₆ (M) ⁺ , 479.

Preparation 3,4-bis(4-methoxyphenyI)-5-vinylisoxazole (XII)

To (XI) (30 mg, 0.063 mmol) TBAF 1M in THF (188 xh) was added dropwise. The reaction mixture was stirred for 24 h at room temperature to give a pale yellow homogeneous solution. The reaction was stopped by adding distilled water and product extracted with ethyl acetate. The organic layer was dried over anhydrous Na ₂ S0 ₄ and the solvent removed under reduced pressure. The product (XII) was isolated as a yellow solid (55% yield) by chromatography on silica gel (hexane/ethyl acetate 8:2) of the reaction crude. 1H NMR (400 MHz, CDCI3, δ): 5.54 (dd, 1H, J= 1.1 and 1 1.5 Hz, vinyl proton); 6.10 (dd, 1H, J= 1.1 and 17.6 Hz, vinyl proton); 6.52 (dd, 1H, J= 11.5 and 17.6 Hz, vinyl proton), 6.84 (d, 2H, J= 9.0 Hz, ArH), 6.92 (d, 2H, J= 9.0 Hz, ArH); 7.17 (d, 2H, J= 9.0 Hz, ArH), 7.39 (d, 2H, J= 9.0 Hz, ArH). ESI-MS: m/z (%): C ₂₅ H ₂₅ SN0 ₆ (M) ⁺ , 261.

Preparation of 3-(5-chlorofuran-2-yl)-4-phenylisoxazol-5-amine (XIII)

A 2.5 M solution of n-butyllithium in hexane (1.068 mL, 2.67 mmol) was added to diisopropylamine (0.413 mL, 2.97 mmol) in anhydrous THF (10 mL) at 0°C under nitrogen atmosphere, using a nitrogen-flushed, three necked flask equipped with a magnetic stirrer, a nitrogen inlet and two dropping funnels. After the mixture had been stirred for 15 min, the reaction mixture was kept at -78 °C, then phenylacetonitrile (0.300 mL, 2.23 mmol) was dropwise added. The yellow reaction mixture was stirred at 0 °C for 1 h, then the solution of 5-chlorofuran-2-carbonitrile oxide (2.23 mmol) in anhydrous THF (10 mL) was added. The orange-colored reaction mixture was allowed to reach room temperature and stirred overnight. After quenching by addition of aqueous NH ₄ C1 solution, the reaction products were extracted three times with ethyl acetate. The organic phase was dried over anhydrous Na ₂ S0 ₄ and then evaporated under vacuum. Column chromatography (silica gel, petroleum ether:ethyl acetate = from 20/1 to 8/2) of the residue affords the 5- (chlorofuran-2-yl)-4-phenylisoxazol-5-amine (105 mg) in 40% yield. Mp 138.5-141 °C (EtOAc/hexane). FT-IR (KBr): 3460, 3402.6, 3115, 2927, 1643, 1518, 1506, 1474, 1413, 1318, 1208, 1148, 1020, 988, 940, 896, 786, 699 cm ^"1 . 1H NMR (400 MHz, CDCI3, δ): 7.45-7.41 (m, 2H,-aromatic protons); 7.39-7.3 l(m, 3H, aromatic protons); 6.36 (d, J = 3.5 Hz, 1H, furyl proton); 6.14 (d, J = 3.5 Hz, 1H, furyl proton); 4.56 (bs, 2H, NH ₂ : exchange with D ₂ 0). ¹³ C NMR (100 MHz, CDC13, δ): 165.8, 153.1, 143.9, 138.4, 130.01, 129.8, 129.3, 128.1, 113.7, 108.1, 93.5. GC-MS (70 eV) m/z (rel.in ): 262 [M ( ³⁷ C1) ⁺ , 11], 260 [M ( ³⁵ C1) ⁺ , 31], 225 (6), 218 (20), 216 (54),197 (8),188 (13),180 (20), 154 (15),153 (16),152 (32),131 (31),129 (100), 127 (16),115 (10),113 (21), 105 (28), 104 (27), 103 (13), 101 (26), 94 (42), 89 (14), 85 1, 77 (54), 76 (1 1), 63 (15), 51 (14).

Preparation of 3-(5-Chlorofuran-2-yl)-5-methyl-4-(4-nitrophenyl)isoxazole (XV)

A solution of the 1 -(4-nitrophenyl)-2-propanone (0.6 mmol) in THF (3 mL) was added dropwise to a suspension of NaH (95% w/w, 1.2 mmol) in THF (6 mL) at 0 °C under nitrogen atmosphere, using a nitrogen-flushed, three necked flask equipped with a magnetic stirrer, a nitrogen inlet and two dropping funnels. After the yellow mixture had been stirred for one hour, a solution of 5-chlorofuran-2-carbonitrile oxide (0.6 mmol) in THF (3 mL) was added. The reaction mixture was allowed to reach room temperature, stirred overnight and then quenched by adding aqueous NH4CI solution. The reaction products were extracted three times with ethyl acetate. The combined organic phases were dried over anhydrous Na ₂ S0 ₄ and then evaporated under vacuum. Column chromatography (silica gel, petroleum ether : ethyl acetate= 19/1) of the residue affords the product in 24 % yield. Mp 153-155 °C (hexane). White powder. FT-IR (KBr): 3144, 3103, 3071, 2929, 2851, 1628, 1601, 1559, 1519, 1441, 1419, 1345, 1239, 1204, 1136, 1105, 1019, 988, 896, 867, 853, 797, 761, 730, 709, 688, 560, 513 cm-1. 1H NMR (400 MHz, CDC1 ₃ , δ): 8.32 (d, 2H, J= 8.3 Hz, aromatic protons); 7.49 (d, 2H, J= 8.3 Hz, aromatic protons); 6.49 (d, 1H, J= 3.5 Hz); 6.21 (d, 1H, J= 3.5 Hz); 2.45 (s, 3H). ¹³ C NMR (100 MHz, CDCI3, δ): 167.7, 151.8, 147.6, 142.7, 138.8, 136.5, 130.8, 123.9, 1 13.7, 113.3, 108.1, 11.4. GC- MS (70 eV) m/z (int.rel.): 306 (M(37C1)+, (15), 304 (M(35C1)+, (45), 264 (33), 262 (100), 245 (7), 217 (13), 215 (15), 199 (7), 188 (9), 187 (12), 152 (9), 89 (16), 73 (8), 63 (6), 43 (52).

Preparation of 4-(3-(5-chIorofuran-2-yI)-5-methylisoxazol-4-yl)benzenamine (XIV)

To a stirred mixture of stannous chloride (298 mg, 1.32 mmol) in hydrochloric acid 37% (1 mL) at 25 °C, was added a solution of 3-(5-chlorofuran-2-yl)-5-methyl-4-(4- nitrophenyl)isoxazole (XV) (100 mg, 0.33 mmol) dissolved in absolute EtOH (8 mL). The reaction mixture was kept under reflux for 4 h. 10% NaOH (10 mL) was added to the reaction mixture till pH 12, and the aqueous phase extracted three times with EtOAc. The combined organic extracts were dried over anhydrous Na2S04 and the solvent removed under reduced pressure. The residue afforded the product with 98% yield. Mp 132-134 °C (EtOAc/hexane). FT-IR (KBr): 3486, 3386, 3143, 3032, 2924, 1626, 1520, 1441, 1411, 1298, 1234, 1204, 1180, 1136, 1016, 988, 941, 899, 838, 799, 739, 565, 518 cm ^"1 . ^l H NMR (300 MHz, CDC13, 5): 7.26 (bs, 2H, NH ₂ : exchange with D ₂ 0); 7.04 (d, 2H, J = 8.4 Hz, aromatic protons); 6.74 (d, 2H, J = 8.4 Hz, aromatic protons); 6.28 (d, 1H, J = 3.5 Hz, furyl proton); 6.13 (d, 1H, J = 3.5 Hz, furyl proton); 2.35 (s, 3H). ¹³ C NMR (100 MHz, CDC1 ₃ , 6): 166.8, 152.7, 146.8, 144.1, 138.4, 131.2, 119.1, 115.4, 114.9, 113.8, 108.1, 11.4. GC-MS (70 eV) m/z (rel.int.): 276 [M ( ³⁷ C1) ⁺ , 34], 274 [M ( ³⁵ C1) ⁺ , 100], 234 (13), 233 (19), 232 (40), 231 (48), 203 (15), 169 (19),168 (29),159 (26),144 (29),142 (12),119 (29),118 (21),117 (10), 113 (10), 89 (11), 77 (7), 65 (6), 63 (6), 51 (4), 43 (14).