反应详情

1.54 g (4.95 mmol) of the above synthesized 2-methyl-6-(4-trifluoromethoxy-phenyl)-nicotinic acid methyl ester in 25 ml of abs. THF was cooled down to −20° C. and reacted with 14.84 ml of DIBAL-H-solution (1.0 M in toluene, 3 eq.) for 0.5 h. Careful quenching with ice/HCl dil., twofold extraction with AcOEt, washing with water, drying over sodium sulfate, and evaporation of the solvents left a crude product which was purified by flash chromatography (SiO2, hexane/AcOEt=1/1) to deliver finally 0.877 g of the title compound as off-white solid of mp. 68–69° C.

1. customCareful quenching with ice/HCl dil., twofold extraction with AcOEt
2. washwashing with water
3. dry with materialdrying over sodium sulfate, and evaporation of the solvents
4. waitleft a crude product which
5. customwas purified by flash chromatography (SiO2, hexane/AcOEt=1/1)