Hydrochloric Acid → Methyl (S)-2-amino-3-cycloheptylpropanoate

Participants

Reaction Conditions

Reaction Steps

At −78° C. 7.80 ml (19.5 mmol) n-butyllithium (2.5 M in hexane) were added dropwise to 2.90 ml (16.2 mmol) (R)-2-isopropyl-3.6-dimethoxy-2,5-dihydropyrazine in 55 ml THF and the mixture was stirred for 2 h at −50° C. Then at −70° C. 4.25 g (17.8 mmol) (iodomethyl)cycloheptane in 15 ml THF were added dropwise, then the mixture was stirred for 30 min at −78° C., for 3 h at 0° C. and overnight at RT. After the addition of water and methanol it was stirred for 20 min at RT. Ethyl acetate was added and the mixture was extracted with saturated, aqueous saline solution. The organic phase was dried and evaporated to dryness by rotary evaporation. The residue was purified by flash chromatography. The fractions containing the product were combined and concentrated by rotary evaporation. The residue obtained was combined with acetonitrile, water and 1M hydrochloric acid and stirred overnight at RT. The acetonitrile was evaporated off and the aqueous phase was neutralised with potassium hydrogen carbonate. It was extracted with ethyl acetate. The combined organic phases were dried and evaporated to dryness by rotary evaporation.

Provenance & Evidence