反应详情

温度

80 °C

To (E)-1-(3-((tert-butyldimethylsilyloxy)methyl)pyridin-2-yl)-3-(dimethylamino)prop-2-en-1-one (crude, 1.03 g, 3.22 mmol, 1 eq.; INT-1) in EtOH (10 mL) was added isopropylhydrazine hydrochloride (430 mg, 3.86 mmol, 1.2 eq.). The mixture was heated at 80° C. for 2 h, cooled, added HCl (6 N, 0.5 mL), and stirred 0/N. The mixture was concentrated and diluted with EtOAc (80 mL) and NaHCO3(sat) (10 mL) solution. The layers were separated and the aqueous layer was extracted with EtOAc three times. The combined organic layers were dried over Na2SO4, concentrated, and purified on silica gel using EtOAc as eluent to give (2-(1-isopropyl-1H-pyrazol-5-yl)pyridin-3-yl)methanol (500 mg, 71%) and (2-(1-isopropyl-1H-pyrazol-3-yl)pyridin-5-yl)methanol (55 mg, 25%) as pale yellow oils. Data for 2-(1-isopropyl-1H-pyrazol-5-yl)pyridin-3-yl)methanol: NMR (400 MHz, CDCl3) δ 8.67 (dd, J=4.7, 1.5 Hz, 1H), 8.0 (d, J=7.8 Hz, 1H), 7.61 (d, J=1.8 Hz, 1H), 7.39 (dd, J=7.8, 4.8 Hz, 1H), 6.37 (d, J=1.8 Hz, 1H), 4.67 (s, 2H), 4.55 (sep, J=6.6 Hz 1H), 1.98-2.05 (br, 1H), 1.47 (d, J=6.6 Hz, 6H). LRMS (M+H+) m/z 218.1 Data for (2-(1-isopropyl-1H-pyrazol-3-yl)pyridin-5-yl)methanol: 1H NMR (400 MHz, CDCl3) δ 8.62 (dd, J=4.8, 1.6 Hz, 1H), 7.72 (d, J=7.6 Hz, 1H), 7.55 (d, J=2.4 Hz, 1H), 7.23 (dd, J=7.6, 4.8 Hz, 1H), 6.99 (dd, J=8.0, 6.5 Hz, 1H), 6.07 (t, J=7.6 Hz, 1H), 4.67 (d, J=7.6 Hz, 2H), 4.58 (sep, J=6.7 Hz, 1H), 1.60 (d, J=6.7 Hz, 1H). MS (ESI) m/z 218.1 [M+H]+.

1. temperaturecooled
2. concentrationThe mixture was concentrated
3. additiondiluted with EtOAc (80 mL) and NaHCO3(sat) (10 mL) solution
4. customThe layers were separated
5. extractionthe aqueous layer was extracted with EtOAc three times
6. dry with materialThe combined organic layers were dried over Na2SO4
7. concentrationconcentrated
8. custompurified on silica gel