Triethylamine → Azetidin-1-yl-(1-methyl-1H-pyrazol-4-yl)-methanone

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Reaction Steps

Methyl-1H-pyrazole-4-carboxylic acid (1.0 g, 7.93 mmol; CAS Nr. 5952-92-1) was combined with DMF (10.0 ml) to give a colorless solution. Et3N (2.41 g, 3.32 ml, 23.8 mmol) and 2-(1H-benzo[d][1,2,3]triazol-1-yl)-1,1,3,3-tetramethylisouronium tetrafluoroborate (TBTU, 2.8 g, 8.72 mmol) were added and the reaction mixture was stirred at RT for 1 h. Azetidine (475 mg, 8.33 mmol) was added and the stirring was continued overnight. DMF was partially removed under high vacuum, H2O and 10% NaHCO3 aq. solution were added to the residue, and the compound was extracted with EtOAc. After drying over Na2SO4, filtration and concentration under vacuum, the crude product was purified by flash chromatography (50 g SiO2—NH2 cartridge; eluent: CH2Cl2/MeOH 95:05). More product was isolated from the aqueous phase by full evaporation and a second chromatography. White solid (971 mg, 74%).

Provenance & Evidence