反应详情

Methyl magnesium chloride (3M in diethyl ether, 3.56 ml, 0.0107 moles) was added dropwise to a stirred solution of (R,E)-2-methyl-N-((1-methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)methylene)propane-2-sulfinamide (1.0 g, 0.035 moles) in dichloromethane (30 ml) at −70° C. under nitrogen. The mixture was allowed to warm to RT to give a cloudy solution and the solution was stirred overnight at RT under nitrogen. Ammonium chloride solution (saturated) was added slowly dropwise to quench the reaction. The mixture was diluted with water and extracted with ethyl acetate (3×20 ml). The organic layer was separated and back-washed with brine (2×30 ml). The organic layer was separated, dried (Na2SO4), filtered and evaporated to give an oil. Yield 1.1 g. 1H NMR (300 MHz CDCl3) ratio 4.5:1 of diastereoisomers. The diastereoisomers were separated by silica gel chromatography using IPA/Heptane 20:80. The top diastereoisomer (100% de) was isolated. Yield 660 mg, 62%. 1H NMR (400 MHz CD30D) δ 7.48 (s, 1H) 4.79, 4.78, 4.76, 4.75, 4.73 (quin, 1H) 3.23, 3.21 (d, 1H) 1.58, 1.57 (d, 3H) 1.21 (s, 9H). MS (ESI) m/z 298 (M+H)+. GC-MS Cl+298 (M+H)+. TLC CH2Cl2:MeOH:NH4OH 95:5:0.5 0.3 UV−ve I2+ve. [α]D=−13.94° (c 1.65, CH3OH).

1. customto give a cloudy solution
2. customto quench
3. customthe reaction
4. extractionextracted with ethyl acetate (3×20 ml)
5. customThe organic layer was separated
6. washback-washed with brine (2×30 ml)
7. customThe organic layer was separated
8. dry with materialdried (Na2SO4)
9. filtrationfiltered
10. customevaporated
11. customto give an oil
12. customThe diastereoisomers were separated by silica gel chromatography
13. customThe top diastereoisomer (100% de) was isolated