Diisopropylethylamine → (2S)-2-methyl-1-[(2-methyl-4-pyridinyl)carbonyl]piperazine

Beteiligte Stoffe

Reaktionsschritte

A mixture of 1,1-dimethylethyl (3S)-3-methyl-1-piperazinecarboxylate (146 mg, 0.73 mmol), 2-methyl-4-pyridinecarboxylic acid (100 mg, 0.73 mmol), HBTU (277 mg, 0.73 mmol) HOBT (112 mg, 0.72 mmol) and DIPEA (0.38 mL, 2.19 mmol) in DMF (20 mL) was stirred at room temperature for 12 hours. The reaction mixture was diluted with DCM and extracted with saturated sodium bicarbonate. The organic layer was collected and the solvent was evaporated off using the rotary evaporator. The solvent was difficult to remove so it was azeotroped twice with toluene. The residual solid was dissolved in DCM and purified using SP4. The fractions containing product were combined and evaporated to dryness on the rotary evaporator. The product was dissolved in 1,4-dioxane (7.5 mL) and 4M HCl in dioxane (2.5 mL) was added and the reaction stirred for 3 h. A few drops of water were then added and the mixture stirred for a further 45 min. The solvent was then evaporated off on the rotary evaporator. To remove the water, the residue was azeotroped twice with toluene. The residual solid was dissolved in methanol and transfered to an SCX column. Once loaded, the material was washed with 2 column volumes of methanol. The product was eluted from the column with 2M ammonia in methanol and the solvent removed under vacuum to give the title compound (70 mg).

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