反应详情

A mixture of 1-[4-(2-phenyl-4-oxazolylmethoxy)benzyl]-3-(2-thienyl)-1H-pyrazole-4-carbaldehyde (1.60 g), diethyl malonate (0.69 g), piperidine (0.12 ml), benzoic acid (0.09 g), and toluene (50 ml) was subjected to azeotropic dehydration for 1 hour. The reaction mixture was poured into dilute hydrochloric acid, and extracted with ethyl acetate. The ethyl acetate layer was washed with saturated aqueous sodium chloride solution, dried (MgSO4), and concentrated. The residue was subjected to silica gel chromatography to obtain a colorless oily substance from the fraction eluted with ethyl acetate-hexane (1:2, volume ratio). Sodium borohydride (105 mg) was added to a mixture of the obtained colorless oily substance, ethanol (20 ml), and tetrahydrofuran (20 ml) at 0° C., and the mixture was stirred at room temperature for 1 hour. The reaction mixture was poured into dilute hydrochloric acid, and extracted with ethyl acetate. The ethyl acetate layer was washed with saturated aqueous sodium chloride solution, dried (MgSO4), and concentrated. The residue was subjected to silica gel chromatography to obtain diethyl [1-[4-(2-phenyl-4-oxazolylmethoxy)benzyl]-3-(2-thienyl)-1H-pyrazol-4-yl]methylmalonate (1.76 g, yield: 83%) as a colorless oily substance from the fraction eluted with ethyl acetate-hexane (1:2, volume ratio).

1. extractionextracted with ethyl acetate
2. washThe ethyl acetate layer was washed with saturated aqueous sodium chloride solution
3. dry with materialdried (MgSO4)
4. concentrationconcentrated
5. customto obtain a colorless oily substance from the fraction
6. washeluted with ethyl acetate-hexane (1:2, volume ratio)
7. additionSodium borohydride (105 mg) was added to a mixture of the obtained colorless oily substance, ethanol (20 ml), and tetrahydrofuran (20 ml) at 0° C.
8. additionThe reaction mixture was poured into dilute hydrochloric acid
9. extractionextracted with ethyl acetate
10. washThe ethyl acetate layer was washed with saturated aqueous sodium chloride solution
11. dry with materialdried (MgSO4)
12. concentrationconcentrated