|
With caesium carbonate;copper(I) oxide; (E)-2-hydroxylbenzaldehyde oxime; In acetonitrile; at 82℃; for 16h; |
EXAMPLE 19; The fluoro bromopyridine (1 eq, Ig), pyrazole (4 eq, 5.023 g), ligand (0.2 eq, 0.196 g), Cu2O (0.05 eq, 51 mg) and Cs2CO3 (2 eq, 4.65 g) were mixed in CH3CN (8 mL) and heated to 82 0C in a sealed vessel for 16 h under N2. The solution was diluted with DCM and filtered through Celite, partitioned with water, and then brine. The product was evaporated in vacuo, and purified by column chromatography (SiO2) with 10 to 20percent EtOAc/hexanes to obtain the major regioisomeric product as a white solid. Then LiBELi (2 eq, 128 mg) was added to this ester intermediate (1 eq, 690 mg) in THF (30 mL) and heated to reflux for 15 h. Then 0.1 N HCl (a few drops) was added and stirred for 1 h, followed by a DCM/H2O partition, and the aqueous layer was basified with NaOH to pH = 9 and extracted with DCM. The combined organic phase was dried to obtain the alcohol as a white solid. Iodine (1.52 eq, l.O58g) in AcOEt (25 ml) was added to an AcOEt (25 mL ) solution of this alcohol (1 eq, 530 mg), followed by Ph3P (1.52 eq, 1.094 g) and imidazole (1.52eq, 0.284 g) over 10 min at RT. The solution was stirred for 1 h and washed with Na2S2O3 and brine. The product was dried in vacuo, and the solid residue was extracted with Hexanes 3 x 70 ml and filtered. The filtration was dried to obtain the iodide product as a white solid. Then KOtBu ( 1.5 eq, 250 mg) was added to N-(diphenylmethylene)- glycine ethyl ester (1.5 eq, 595 mg) in THF at RT and stirred for 10 min. To this solution was added the iodide intermediate (1 eq, 450 mg) in THF (5 mL) at -78 0C, and the mixture was slowly warmed to RT over 2 h. An additional 1 eq of KOtBu was added to the solution at RT and stirred for 50 h at RT. The mixture was quenched with NH4Cl and extracted with DCM, washed with H2O and then brine, and dried in vacuo. The residue was purified by column chromatography (hex/AcOEt - 20percent) to obtain the product. This intermediate (1 eq. 200 mg) was dissolved in saturated 7 N NH3/MeOH (7 mL) solution and heated to 60 0C for 24 h in a sealed tube. The reaction mixture was dried in vacuo and, the residue was dissolved in 5 ml THF and 1 N HCl (2 mL) at RT and heated to 60 0C for 20 min. The THF was removed in vacuo. The aqueous layer was washed with Et2O, dried in vacuo to obtain the amino carboxamide as a white solid HCl-salt. The amide intermediate (1 eq, 68 mg), triflate (1.2 eq, 82 mg), Pd2(DBA)3 (0.1 eq. ), Xantphos (0.2 eq, ) and Cs2CO3 (2.4 eq, 186 mg) were combined in dioxane (2 mL) under N2 and heated to 75 0C for 13 h. The mixture was cooled and diluted with CH2C12 (2 mL), filtered through Celite, and the CH2CI2 removed in vacuo, and Et2psi was added to the filtrate and extracted with 3 N HCl (3 x 10 mL). The combined aqueous layer was basified with Na2CO3 to pH== 9 at 0 0C and extracted with AcOEt (3 xlO mL). The combined organic layer was dried in vacuo to obtain the crude product as a light yellow oil. Lastly, LiOH (0.5 M, 3 mL) was added to this ester in THF/MeOH at 0 0C <n="51"/>and stirred for 20 h. Then AcOH was added to acidify to pH= 7 at 0 0C and HPLC purification provided the product. 1HNMR, CD3OD delta 8.48 (d, IH), 8.30 (d, IH), 7.99(dd, IH), 7.74 (m, IH), 6.43(d, IH), 4.37 (t, IH), 3.50(d, 2H), 2.88 (m, 2H), 2.29 (br, 2H), 1.62 (m, 4H); LCMS m/z 374 (M+H). |
| 29 g |
With copper(l) iodide; caesium carbonate; trans-N,N'-dimethylcyclohexane-1,2-diamine; In N,N-dimethyl-formamide; at 90℃; for 7h; |
Reference Example 27: Ethyl-1-(5-fluoropyridin-2-yl)-1H-pyrazol-3-carboxylate To a solution of <strong>[5932-27-4]ethyl-1H-pyrazole-3-carboxylate</strong> (25.0 g, 178.4 mmol) and 2-bromo-5-fluoropyridine (47.1 g, 267.6 mmol) in DMF (300 mL), copper(I) iodide (8.5 g, 44.6 mmol), rac-trans-N,N'-dimethylcyclohexane-1,2-diamine (28.1 mL, 178.4 mmol) and Cs2CO3 (116.2 g, 356.8 mmol) were added, and the resulting mixture was stirred for 7 hours at 90°C. The reaction mixture was allowed to cool to room temperature, then water and EtOAc were added thereto, followed by filtration through Celite?. The organic layer was taken out from the filtrate, washed with a saturated aqueous solution of sodium chloride, dried over Na2SO4, then the drying agent was filtered off, and then the solvent was distilled off under reduced pressure. The obtained residue was purified by column chromatography (HP-Sil 50 g, hexane/EtOAc = 70/30 to 0/100). The obtained solid was stirred and washed in hexane/EtOAc = 4/1 and filtered out to obtain the title compound (29.0 g) (colorless solid). MS (ESI pos.) m/z: 236 [M+H]+ |
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