反应详情

Dissolve 3′-chloro-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4-carboxylic acid tert-butyl ester (1.29 g, 4.35 mmol) in tetrahydrofuran (12 mL) and water (6 mL). Add potassium carbonate (1.32 g, 9.56 mmol) then 4-hydroxymethylbenzeneboronic acid (0.924 g, 6.08 mmol) and degas with nitrogen for 15 min. Add tri-n-butylphosphine tetrafluoroborate (50 mg, 0.174 mmol) and tris(dibenzylideneacetone)dipalladium(0) (80 mg, 0.0869 mmol) and reflux for 20 hr. Cool to room temperature then dilute with saturated aq. sodium bicarbonate and extract 3 times with ethyl acetate. Dry (sodium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 3:97 methanol (with 2 M ammonia): DCM), to give a yellow oil. Dissolve the oil in methanol and add ammonium chloride then sonicate the mixture for 10 min. Evaporate the solution to give 3′-(4-hydroxymethyl-phenyl)-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4-carboxylic acid tert-butyl ester as a yellow semisolid (0.565 g, 35%). MS (ES): m/z=371 [M+H]+.

1. extractionextract 3 times with ethyl acetate
2. dry with materialDry (sodium sulfate)
3. filtrationfilter
4. concentrationconcentrate
5. custompurify
6. wash(silica gel chromatography, eluting with 3:97 methanol (with 2 M ammonia): DCM)
7. customto give a yellow oil
8. customthen sonicate the mixture for 10 min
9. customEvaporate the solution