Benzeneacetic acid, 3,4-dimethoxy-, methyl ester → 6-(3,4-Dimethoxy-benzyl)-1-[1-(1-hydroxy-ethyl)-4-phenyl-butyl]-3-ethyl-1,5-dihydro-pyrazolo[3,4-d]pyrimidin-4-one

Beteiligte Stoffe

Reaktionsschritte

1.0 g (3.03 mmol) of 5-amino-1-[1-(1-hydroxy-ethyl)-4-phenyl-butyl]-3-ethyl-1H-pyrazole-4-carboxamide, 1.60 g of potassium tert-butoxide and 1.40 g (19 mmol) of methyl 3,4-dimethoxyphenylacetate are refluxed overnight in 20 ml of ethanol. The solvent is removed in vacuo, the residue is taken up in dichloromethane, the mixture is extracted with 1N HCl, the organic phase is dried over Na2SO4 and evaporated on a rotary evaporator. Purification by chromatography (cyclohexane/EA=2:1, 1% formic acid) and separation of the diastereomers by chromatography gives 232 mg (16%) of the diastereomer which elutes more rapidly, Rf=0.2 (cyclohexane/ethyl acetate=2:1) and 150 mg (10%) of the diastereomer which elutes more slowly, Rf=0.15 (cyclohexane/ethyl acetate=2:1).

Herkunft & Nachweise