反应详情

In an autoclave, 6.4 g (36.7 mmol) of 2-(tetrazol-5-yl)-benzaldehyde (Step 61.1) in 50 ml of toluene are heated at 110° C. for 1.5 hours with ≈3 g of isobutene and 0.432 ml of methanesulfonic acid. When cold the reaction mixture is diluted with 300 ml of ethyl acetate, washed four times with water and once with brine, dried (Na2SO4) and concentrated by evaporation. Column chromatography (SiO2; hexane/ethyl acetate=4:1) and crystallization from hexane with a small amount of diethyl ether at −20° C. yield 2-(2-tert-butyl-tetrazol-5-yl)-benzaldehyde; TLC: Rf=0.36 (hexane/ethyl acetate=10:1).

1. washwashed four times with water
2. dry with materialonce with brine, dried (Na2SO4)
3. concentrationconcentrated by evaporation
4. customColumn chromatography (SiO2; hexane/ethyl acetate=4:1) and crystallization from hexane with a small amount of diethyl ether at −20° C.