Diisopropylethylamine → tert-Butyl 5-(9-(pyridin-4-yl)-3,9-diazaspiro[5.5]undecane-3-carbonyl)isoindoline-2-carboxylate

Participants

Reaction Steps

2-(tert-Butoxycarbonyl)isoindoline-5-carboxylic acid (0.5 g, 0.0019 mol) ([CAS: 149353-71-9] available commercially from Milestone, for example), O-(1H-benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate (0.6 g, 0.0019 mol) and 1-hydroxybenzotriazole hydrate (0.26 g, 0.0019 mol) were dissolved in tetrahydrofuran, under protecting gas, and stirred for 30 min at RT. A solution of 3-(pyridin-4-yl)-3,9-diazaspiro[5.5]undecane dihydrochloride (F-09) (0.5 g, 0.0019 mol) and diisopropylethylamine (DIPEA) (0.86 g, 0.066 mol) in tetrahydrofuran was added, and the reaction mixture was stirred for 15 h at RT. Tetrahydrofuran was then removed in vacuo, the residue was taken up in ethyl acetate and sat. sodium hydrogen carbonate solution, and the phases were separated. The aqueous phase was extracted with ethyl acetate and the combined organic phases were in turn washed with sat. sodium chloride solution, dried over sodium sulfate and concentrated in vacuo. The crude product was purified by column chromatography (ethyl acetate/methanol 10:1+1% ammonia solution (25% aq.)). Yield: 0.85 g (94%)

Provenance & Evidence