Pyridazine → 3-(1-Ethoxycarbonyl-1,4-dihydropyridazin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine

Ethyl chloroformate (3.38 g) was added dropwise with stirring to a solution of 2-phenylpyrazolo[1,5-a]pyridine (2.54 g) and pyridazine (5.00 g) in methylene chloride (5.0 ml) at 10° C. After being stirred at 10° C. for 1 hour and then at room temperature for 2 hours, the reaction mixture was poured onto ice-water (100 ml), and extracted with ethyl acetate. The combined extracts were washed with saturated sodium chloride aqueous solution (100 ml), dried over magnesium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel (150 g) with a mixture of chloroform and n-hexane (1:1) as an eluant. The fractions containing main-product [compound (A)] were combined and evaporated in vacuo to give 3-(1-ethoxycarbonyl-1,4-dihydropyridazin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine (2.42 g).

1. waitat room temperature for 2 hours
2. additionthe reaction mixture was poured onto ice-water (100 ml)
3. extractionextracted with ethyl acetate
4. washThe combined extracts were washed with saturated sodium chloride aqueous solution (100 ml)
5. dry with materialdried over magnesium sulfate
6. customevaporated in vacuo
7. customThe residue was chromatographed on silica gel (150 g) with a mixture of chloroform and n-hexane (1:1) as an eluant
8. additionThe fractions containing main-product [compound (A)]
9. customevaporated in vacuo

ORD record

ord-c7262b43437944ed8a03a8289694a8d5

Source dataset

uspto-grants-1992_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05155114