Potassium tert-butoxide → 2-(5-Bromo-pyrazin-2-yl)-1-oxo-2,8-diaza-spiro[4.5]decane-8-carboxylic acid tert-butyl ester

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Reaction Steps

To a solution of 4-[2-(5-bromo-pyrazin-2-ylamino)-ethyl]-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-ethyl ester (0.825 g, 1.81 mmols) in THF (10 mL) was added a 1 M solution of potassium t-butoxide in THF (2.0 mL), and allowed to stir at room temperature. After 1 hour LCMS was taken and reaction was not complete. After 5 hours, an additional 1 mL of potassium t-butoxide was added. The reaction mixture was allowed to stir for 16 hours. The three reaction mixtures were diluted with ethyl acetate (20 mL), quenched with water (5 mL). The aqueous layer was extracted with EtOAc (2×10 mL). The combined organic layers were washed with brine, dried over Na2SO4, and concentrated under vacuum to afford crude product. Purification over silica gel eluting with methanol in dichloromethane (0-10%) afforded 0.186 g (25%) of the title compound.

Provenance & Evidence