Triethylamine → 3'-chloro-4-(1-ethyl-3-methyl-1H-pyrazol-4-ylmethyl)-3,4,5,6-tetrahydro-2H-[1,2']bipyrazinyl

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Reaction Steps

Combine 3′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl dihydrochloride (2.21 g, 8.18 mmol), 1-ethyl-3-methyl-1H-pyrazole-4-carbaldehyde (1.3 g, 9.40 mmol) and triethylamine (1.31 mL, 9.40 mmol) in dichloroethane (50 mL). Add glacial acetic acid (0.85 mL) followed by sodium triacetoxyborohydride (2.99 g, 14.1 mmol). Stir at room temperature for 20 hr. Dilute with saturated aq. sodium bicarbonate then extract three times using DCM. Dry (sodium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 4.5:95.5 methanol (with 2 M ammonia):DCM), to give 3′-chloro-4-(1-ethyl-3-methyl-1H-pyrazol-4-ylmethyl)-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl as a yellow oil (1.702 g, 65%). MS (ES): m/z=321 [M+H]+.

Provenance & Evidence