Hydrochloric Acid → Diniconazole

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

In a nitrogen atmosphere, 0.338 g (1.8 mmoles) of (+)-norephedrine hydrochloride was suspended in 5 ml of 1,2-dichloroethane, and after cooling to -30° C., a solution of 0.0681 g (1.8 mmoles) of sodium borohydride in 1 ml of dimethylformamide was added. On raising the temperature of the resulting suspension from -30° C. to room temperature over 2 hours, 87 ml of hydrogen gas was generated. Thereafter, a solution of 0.39 g (1.2 mmoles) of (E)-1-(2,4-dichlorophenyl)-2-(1,2,4-triazol-1-yl)-4,4-dimethyl-1-penten-3-one (E/Z=99.9/0.1) in 4 ml of 1,2-dichloroethane was added to this suspension at room temperature, and then stirring was carried out for 23 hours. Thereafter, 6 ml of 2M hydrochloric acid was added, followed by stirring for 2 hours. The organic layer was washed with water, dried and concentrated under reduced pressure. The residue was purified on a column packed with 2 g of silica gel with a chloroform solvent and then concentrated under reduced pressure to obtain 0.39 g of (-)-(E)-1-(2,4-dichlorophenyl)-2-(1,2,4-triazol-1-yl)-4,4-dimethyl-1-penten-3-ol as a crude crystal. By gas-chromatographic analysis, it was found that the conversion was 96.4%, and the composition of the reaction product was: E-form alcohol, 98.3% and Z-form alcohol, 1.7% (Z-form alcohol was produced through isomerization of the ketone compound to the Z-form, followed by reduction of the carbonyl group).

Herkunft & Nachweise