反应详情

1 g of β-hydroxyethyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-chlorophenyl)-pyridine-5-carboxylate is stirred overnight in a mixture of 15 ml of pyridine and 15 ml of acetic anhydride. The mixture is poured into water and extracted with ethyl acetate and the extract is washed with 1 N HCl, water, sodium bicarbonate solution and water again, dried and concentrated. The evaporation residue is crystallized with ethanol, filtered off with suction and washed with ethanol. 800 mg of a yellow-coloured compound of melting point 166° C. which is identical to the compound from Preparation Example 1, process variant A are obtained.

1. extractionextracted with ethyl acetate
2. washthe extract is washed with 1 N HCl, water, sodium bicarbonate solution and water again
3. customdried
4. concentrationconcentrated
5. customThe evaporation residue is crystallized with ethanol
6. filtrationfiltered off with suction
7. washwashed with ethanol
8. custom800 mg of a yellow-coloured compound of melting point 166° C. which is identical to the compound from Preparation Example 1, process variant
9. customA are obtained