Sodium triacetoxyborohydride → 2-chloro-1'-[[1-(3-chloro-2-pyridyl)-3-methyl-pyrazol-4-yl]methyl]-4,4-difluoro-spiro[5H-thieno[2,3-c]pyran-7,4'-piperidine]

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Reaction Steps

To a solution of 2′-chloro-4′,4′-difluoro-4′,5′-dihydrospiro[piperidine-4,7′-thieno[2,3-c]pyran] (0.2 g, 0.71 mmol) in 1,2-dichloroethane (5 mL) are added 1-(3-chloro-2-pyridyl)-3-methyl-pyrazole-4-carbaldehyde (0.19 g, 0.86 mmol) and a few drops of acetic acid. The reaction mixture is stirred at room temperature for 1 hour. Sodium triacetoxyborohydride (0.315 g, 1.43 mmol) is added and stirred at room temperature for 14 hours. After completion, the reaction mixture is diluted with dichloromethane and washed with saturated sodium bicarbonate solution and brine. The organic phase is dried over sodium sulfate and concentrated in vacuo. The crude mixture is purified by HPLC to yield 0.195 g (56%) of 2-chloro-1′-[[1-(3-chloro-2-pyridyl)-3-methyl-pyrazol-4-yl]methyl]-4,4-difluoro-spiro[5H-thieno[2,3-c]pyran-7,4′-piperidine]. MS (m/z): 485 (M+1).

Provenance & Evidence