反应详情

7-[3-Hydroxypropylamino]-5-methyl-1H-pyrazolo[4,3-b]-pyridine,* (0.15 g, 0.73 mmol) was suspended in dry pyridine (2 ml) and 1,4-dioxan (2 ml) and cooled in an ice-bath. A solution of valeryl chloride (0.18 ml, 2.1 equiv.) in dioxan (1.5 ml) was added dropwise with stirring and then left at room temperature overnight. Methanol (10 ml) was added and the resulting solution stirred for 1 h and then solvents removed under reduced pressure. The residue was chromatographed on basic alumina eluting initially with ethyl acetate rising to 30% methanol/ethyl acetate. After removal of solvent a colourless oil was obtained, which on trituration with ether gave the title compound as a white solid, m.p. 92°-95° C.

1. stirringthe resulting solution stirred for 1 h
2. customsolvents removed under reduced pressure
3. customThe residue was chromatographed on basic alumina eluting initially with ethyl acetate rising to 30% methanol/ethyl acetate
4. customAfter removal of solvent a colourless oil
5. customwas obtained