1-Phenyl-1H-pyrazole-4-carbaldehyde → 3'-chloro-4-(1-phenyl-1H-pyrazol-4-ylmethyl)-3,4,5,6-tetrahydro-2H-[1,2']bipyrazinyl

Beteiligte Stoffe

Reaktionsschritte

Stir together 3′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl (1.6 g, 8.43 mmol) and 1-phenyl-1H-pyrazole-4-carbaldehyde (2.17 g, 12.6 mmol) in dry tetrahydrofuran (10 mL) at room temperature for 15 min., under nitrogen. Add sodium triacetoxyborohydride (2.68 g, 12.6 mmol) and stir reaction for 1 hr. Quench reaction mixture with saturated aq. sodium bicarbonate (50 mL), then extract with DCM (3×50 mL) and pass through an IST Phase Separator Frit®. Concentrate and purify (silica gel chromatography, eluting with 5:95 methanol:DCM) and concentrate all fractions containing product. Pass the mixture through a CBA column to retain the product, wash with methanol and then elute with 2 M ammonia in methanol. Evaporate the ammonia methanol solution and purify (silica gel chromatography, eluting with 0:100 then 5:95 methanol:DCM). Concentrate, wash with diethyl ether and dry in vacuum oven to give 3′-chloro-4-(1-phenyl-1H-pyrazol-4-ylmethyl)-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl as brown powder (2.25 g, 76%). MS (ES): m/z=355 [M+H]+.

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