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2-methyl-5-trifluoromethyl-2H-pyrazole-3-boronic acid: <strong>[154471-65-5]1-methyl-3-trifluoromethyl-1H-pyrazole</strong> (1.00 g, 6.66 mmol) was dissolved in THF (25 mL) in an oven-dried round bottom flask and cooled to-78 C in an acetone/dry ice bath. 2.5 M n-butyl lithium/hexane (3.196 ml, 7.99 mmol) was added drop wise to the stirred solution followed by drop wise addition of triisopropyl borate (5.01 g, 26.64 mmol). The mixture was warmed to room temperature and stirred for three hours. The reaction mixture was adjusted to pH 6 with IN HCl solution followed by the removal of THF under vacuum. The aqueous phase was extracted with EtOAc (3x100 ml). The combined organic phase was washed with brine and dried over anhydrous MgS0(sub>4, filtered and evaporated to give 2-methyl-5-trifluoromethyl-2H-pyrazole-3-boronic acid (1.12 g, 5.80 mmol, 87 % yield) as a white solid: LCMS m/z (%) = 195 (M+H, 100). 1H NMR (400 MHz, DMSO-d6) delta: 8.37-8.40 (m, 2H), 7.57 (dd, J= 4.0 Hz, 1H), 4.06 (s, 3H).
Preparation 7[1 -Methyl-3-(trifluoromethyl)-1 H-pyrazol-5-yllboronic acidTo a stirred solution of 1 -methyl-3-(thfluoronnethyl)-1 H-pyrazole (1 .89 g, 12.6 mmol) in anhydrous tetrahydrofuran (20 ml_) under nitrogen cooled to -78C was added n- butyllithium (8.3 mL, 1 .6 M solution in hexanes, 13.2 mmol) slowly over 5 minutes. The resulting yellow solution was stirred at -78C for 1 hour and trimethyl borate (1 .56 mL, 13.9 mmol) was then added slowly. The reaction flask was covered in foil and allowed to warm to room temperature for 16 hours. The white solution was quenched with aqueous 1 M hydrogen chloride solution (10 mL) and stirred at room temperature for 1 .5 hours. The mixture was extracted with ethyl acetate (2 x 30 mL), dried with anhydrous magnesium sulphate and evaporated in vacuo to give an off-white foam (2.1 1 g). The foam was triturated with dichloromethane, filtered and dried in vacuo to afford the title compound as a white solid (1 .57 g, 64%).1H NMR (400 MHz, MeOH-d4): delta 4.04 (s, 3H), 6.89 (s, 1 H).LCMS Rt = 1 .1 1 minutes MS m/z 194 [MH]+ 192 [M-H]-,
With hydrogenchloride; diisopropylamine; In tetrahydrofuran;
4B Preparation of <strong>[154471-65-5]1-methyl-3-trifluoromethylpyrazol</strong>-5-yl-boronic acid A solution of <strong>[154471-65-5]1-methyl-3-trifluoromethylpyrazol</strong> (2 g) in 10 ml THF is cooled under an inert gas atmosphere to -78 C. A 2 M solution of LDA (9.75 ml) is added dropwise. The mixture is stirred to 10 C. for 1 h and cooled to -75 C. Trimethylborate (5.8 ml) is added and after stirring for 1 h at -75 C. the mixture is stirred overnight at ambient temperature. The resulting reaction solution is added to 10% hydrochloric acid (15 ml). The water phase is extracted 3 times with ethyl acetate and the combined organic phases are washed with water and a saturated sodium chloride solution. The organic phase is dried and evaporated and the residue is crystallized from water. After drying, one obtains the title compound as nearly colorless crystals (1.12 g) of mp. 138 C.
With hydrogenchloride; diisopropylamine; In tetrahydrofuran;
4B Preparation of <strong>[154471-65-5]1-methyl-3-trifluoromethylpyrazol</strong>-5-yl-boronic acid A solution of <strong>[154471-65-5]l-methyl-3-trifluoromethylpyrazol</strong> (2 g) in 10 ml THF is cooled under an inert gas atmosphere to -78 C. A 2 M solution of LDA (9.75 ml) is added dropwise. The mixture is stirred to 10 C for 1 h and cooled to -75 C. Trimethylborate (5.8 ml) is added and after stirring for 1 h at -75 C the mixture is stirred overnight at ambient temperature. The resulting reaction solution is added to 10 % hydrochloric acid (15 ml). The water phase is extracted 3 times with ethyl acetate and the combined organic phases are washed with water and a saturated sodium chloride solution. The organic phase is dried and evaporated and the residue is crystallized from water. After drying, one obtains the title compound as nearly colorless crystals (1.12 g) of mp. 138C.
With sodium carbonate;tetrakis(triphenylphosphine) palladium(0); In 1,2-dimethoxyethane; ethanol; at 110℃; for 0.5h;Inert atmosphere; Microwave irradiation;
Examples 71-73Preparation of (2-fluorophenyl)-N-{5-[1-methyl-3-(trifluoromethyl)pyrazol-5-yl](2-thienyl)}carboxamide (135) 1-Methyl-3-trifluoromethylpyrazole-5-boronic acid (97 mg, 0.5 mmol) and <strong>[13195-50-1]2-bromo-5-nitrothiophene</strong> (104 mg, 0.5 mmol) was dissolved in 2 mL dimethoxyethane and 2 mL EtOH. The 1 mL of 2 M Na2CO3 was added and the mixture was bubbled with Ar for 1 min before add tetrakis(triphenylphosphine)-palladium(0) (Pd(Ph3P)4, 60 mg, 0.05 mmol). The reaction was heated at 110° C. for 30 min under microwave initiator. The reaction mixture was worked-up with EtOAc extraction and product was purified by flash column and afforded 133 as yellow solid. Following hydrogenation under standard conditions, to a solution of 134 (37 mg, 0.15 mmol) in CH2Cl2 (10 mL) was added 2-fluorobenzoyl chloride, N,N-diisopropylethylamine (DIEA, 0.5 g, 0.7 mL, 4 mmol), and a catalytic amount of DMAP. The mixture was stirred for 2 h at room temperature. The reaction was quenched with saturated NaHCO3 (20 mL) and extracted with EtOAc (20 mL.x.2). The combined organic layers were dried (Na2SO4) and concentrated in vacuo. The residue was dissolved in THF (2 mL) and MeOH (2 mL). 1M NaOH (2 mL) was added and stirred for 0.5 h at room temperature. The reaction mixture was concentrated and worked-up with EtOAc-Brine. The crude product was purified by flash column and compound 135 (2.7 mg, 5percent) was obtained as yellow solid. LC-MS: calcd. for C16H11F4N3OS: 370 (M+1).
With sodium carbonate;tetrakis(triphenylphosphine) palladium(0); In 1,2-dimethoxyethane; ethanol; water; at 110℃; for 0.5h;Inert atmosphere; Microwave irradiation;
Example 29Preparation of (2-chlorophenyl)-N-{2-[1-methyl-3-(trifluoromethyl)pyrazol-5-yl](1,3-thiazol-5-yl)}carboxamide (67) Preparation of 2-[1-methyl-3-(trifluoromethyl)pyrazol-5-yl]-5-nitro-1,3-thiazole (65): A mixture of <strong>[3034-48-8]<strong>[3034-48-8]2-bromo-5-nitrothiazol</strong>e</strong> (209 mg, 1 mmol), (1-methyl-3-(trifluoromethyl)-1H-pyrazol-5-yl)boronic acid (194 mg, 1 mmol), tetrakis(triphenylphosphine)-palladium(0) (Pd(Ph3P)4, 57 mg) and sodium carbonate (212 mg) in 3 ml DME, 0.5 ml EtOH and 0.5 ml water was heated under Ar in microwave reactor at 110° C. for 30 min. The reaction mixture was worked up with EA/brine. Org. phase was concentrated and then subjected to silica gel flash chromatography (0-30percent B; A: hexane; B: 50percent EA in hexane) to furnish 37.5 mg of 2-[1-methyl-3-(trifluoromethyl)pyrazol-5-yl]-5-nitro-1,3-thiazole (65) as light yellow solid (yield: 13.5percent; purity>90percent).
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