Lithium borohydride → HCID 24985460, compound

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Reaction Steps

To an ice-cold solution of ethyl 4-chloro-5-cyano-1-(2,2,2-trifluoroethyl)-1H-indole-2-carboxylate (0.45 g, 1.36 mmol) in THF (12 mL), under N2, was added LiBH4 (2 M THF solution, 2.04 mL, 4.08 mmol). The mixture was stirred at rt for 8 h. Additional LiBH4 (2M THF solution, 3 mL, 6 mmol) was added and stirred at rt for 60 h. The mixture was cooled in an ice bath and quenched by sequential dropwise addition of water and 1N HCl (exothermic). The mixture was partitioned between EtOAc and water. The organic phase was washed with sat'd brine, dried (Na2SO4) and concentrated in vacuo. The residue was purified by flash chromatography (10-80% EtOAc-hexanes gradient) to afford a mixture of the title compounds. A second flash chromatography (0-2% MeOH—CH2Cl2 gradient) afforded 4-chloro-2-(hydroxymethyl)-1-(2,2,2-trifluoroethyl)-1H-indole-5-carbonitrile (Example 10) as a white solid (0.25 g, 63% yield) (MS (ES) m/z 289 (M+1)) and 2-(hydroxymethyl)-1-(2,2,2-trifluoroethyl)-1H-indole-5-carbonitrile (Example 11) (0.021 g, 6% yield) (MS (ES) m/z 255 (M+1)).

Provenance & Evidence