Thionyl Chloride → {(S)-1-Methyl-2-[7-(4-pyridin-2-yl-piperazin-1-ylmethyl)-furo[2,3-g]indazol-1-yl]-ethyl}-carbamic acid benzyl ester

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Reaction Steps

A solution of the product from Example 3, Step B (0.18 g, 0.475 mmol) in dichloromethane (20 mL) was cooled (ice bath) and thionyl chloride (0.052 mL, 0.71 mmol) added. The mixture was stirred for 30 min and then evaporated to a residue which was dissolved in dichloromethane (20 mL); this solution was evaporated and the residue dried under a vacuum. The residue was dissolved in dichloromethane (20 mL) and 1-(2-pyridyl)piperazine (0.5 mL, 3.4 mmol) was added, and the mixture was stirred at room temperature for one hour at which point additional 1-(2-pyridyl)piperazine (0.9 mL) was added. Solvent was removed by evaporation (45° C.) and THF (10 mL) was added, followed by heating the mixture at reflux temperature for one hour. This reaction mixture was evaporated and the residue dissolved in methanol (25 mL) and triethylamine (1.5 mL) followed by evaporation of this mixture to a residue which was purified by chromatography (silica gel, hexane/ethyl acetate) to give a foamy solid (0.21 g, 84%): LC/MS m/z 525 [M+H]+.

Provenance & Evidence