Diisopropylamine → 4-Pyrazin-2-yl-butyric acid ethyl ester

Temperature

-20 °C

Butyllithium (1.6 M in hexane solution, 10 ml, 16 mmol) was added dropwise to a solution of diisopropylamine (2.25 ml, 16 mmol) in anhydrous THF (50 ml) at −20° C. under a nitrogen atmosphere. The mixture was stirred at −20° C. for 30 minutes and after cooling at −70° C. a solution of 2-methyl-pyrazine (1.47 ml, 16 mmol) in THF (10 ml) was added dropwise. After 15 minutes, a solution of 3-bromo-propionic acid ethyl ester (2.54 ml, 19.2 mmol) in THF (10 ml) was added and the mixture maintained at −70° C. for 2 hours and then stirred at room temperature overnight. The reaction was then quenched with a saturated solution of NH4Cl and extracted with ethyl acetate, the organic phase was dried (Na2SO4) and evaporated. The residue was purified by flash chromatography (hexane/ethyl acetate from 9/1 to 1/1 respectively) to give the title compound (1 g, 33% yield).

1. additionwas added dropwise
2. waitAfter 15 minutes
3. temperaturethe mixture maintained at −70° C. for 2 hours
4. stirringstirred at room temperature overnight
5. customThe reaction was then quenched with a saturated solution of NH4Cl
6. extractionextracted with ethyl acetate
7. dry with materialthe organic phase was dried (Na2SO4)
8. customevaporated
9. customThe residue was purified by flash chromatography (hexane/ethyl acetate from 9/1 to 1/1 respectively)

ORD record

ord-220e78d7826449888991f35315f49509

Source dataset

uspto-grants-2012_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08334286B2