Potassium Carbonate → 3'-m-Tolyl-2,3,5,6-tetrahydro-[1,2']bipyrazinyl-4-carboxylic acid t-butyl ester

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Reaction Steps

Dissolve 3′-chloro-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4-carboxylic acid t-butyl ester (6.0 g, 20.2 mmol) and 3-methylbenzeneboronic acid (3.3 g, 24.0 mmol) in dimethoxyethane (20 mL) and water (10 mL). Add tetrakis(triphenylphosphine) palladium(0) (2.3 g, 2.0 mmol) and potassium carbonate (7.5 g, 54 mmol). Heat for 17 hr. at 102° C. and allow to cool about 1.5 hr. to room temperature. Partition reaction mixture between ethyl acetate and water. Separate layers. Wash organic layer with brine, dry (sodium sulfate), filter, concentrate and purify (silica gel chromatography eluting with 10:90 to 20:80 ethyl acetate:hexanes), to give 3′-m-tolyl-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4-carboxylic acid t-butyl ester (3.3 g, 47%). MS (ES): m/z=355 [M+H]+.

Provenance & Evidence