反应详情

6-[3-(trifluoromethyl)phenyl]-4-pyridazinecarboxylic acid (30 g, 0.112 mole, Compound No. 2), diphenylphosphorylazide (33.9 g, 0.123 mole) and triethylamine (17 g, 0.168 mole) were refluxed under N2 in t-butanol (250 mL) for 4 h. The mixture was then partitioned between ethyl acetate and water. The organic layer was dried (MgSO4), filtered through silica gel and evaporated in vacuo to give a crude solid which can be utilized as is in the next step or chromatographed on a Prep-500 to give [6-[3-(trifluoromethyl)phenyl]-4-pyridazinyl]carbamic acid, 1,1-dimethylethyl ester (Compound No. 3) as a white solid which was recrystallized from cyclohexane/ethyl acetate.

1. customThe mixture was then partitioned between ethyl acetate and water
2. dry with materialThe organic layer was dried (MgSO4)
3. filtrationfiltered through silica gel
4. customevaporated in vacuo
5. customto give a crude solid which
6. customchromatographed on a Prep-500