反应详情

A solution of 1.51 g of 6-(4-fluorophenyl)-3-pyridinecarboxaldehyde and 1.10 g of 2-propyl-1,3-propanediol in 50 ml of toluene was treated with 10 drops of 10 percent (v/v) sulphuric acid. The mixture was heated to boiling for 1.5 hours, whereby moist toluene was distilled off and replaced by fresh toluene. Then, the reaction mixture was neutralized with triethylamine and, after cooling, washed three times with water, dried over sodium sulphate and concentrated. Chromatographic purification of the residue on 60 g of silica gel with toluene/acetone (vol. 99:1) and two-fold recrystallization of the trans/cis mixture from hexane/ethyl acetate (vol. 1:1) gave 0.51 g of pure 5-(trans-5-propyl-1,3-dioxan-2-yl)-2-(4-fluorophenyl)pyridine; m.p. (C-SA) 106.5° C., SA -N 117.5° C., cl.p. (N-I) 163° C.

1. temperatureThe mixture was heated
2. distillationwhereby moist toluene was distilled off
3. temperatureafter cooling
4. washwashed three times with water
5. dry with materialdried over sodium sulphate
6. concentrationconcentrated
7. customChromatographic purification of the residue on 60 g of silica gel
8. customwith toluene/acetone (vol. 99:1) and two-fold recrystallization of the trans/cis mixture from hexane/ethyl acetate (vol. 1:1)