Potassium Carbonate → 2-(2-Pyrrolidin-1-yl-ethyl)-2,4,6,7-tetrahydro-pyrazolo[4,3-c]pyridine-5-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

1,4,6,7-Tetrahydro-pyrazolo[4,3-c]pyridine-5-carboxylic acid tert-butyl ester (1.8 g, 8.06 mmol)(EP1057814, Example 2c) was added to 1-(2-chloro-ethyl)-pyrrolidine hydrochloride (1.65 g, 9.67 mmol) and potassium carbonate (3.34 g, 24.2 mmol) in N,N-dimethylformamide (35 ml) and the mixture was heated at 65° C. for 26 hours, then cooled to room temperature and stirred for 72 hours. The solvent was evaporated under reduced pressure and the residue was dissolved in 2N sodium hydroxide solution. The aqueous mixture was extracted with ethyl acetate (×2) and the combined organic layers were dried over magnesium sulphate and evaporated under reduced pressure. The residue was purified by chromatography on silica gel using ammonium hydroxide, methanol and ethyl acetate in dichloromethane as eluant (gradient from 0:0:50:50 to 0:0.1:50:50 to 0.5:5:0:95) to give the title compounds from preparation 228-A and preparation 228-B as a mixture of isomers (300 mg). LRMS: m/z ES+ 321 [MH+]

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