Diisopropylethylamine → (R)-2-phenoxymethyl-5-(1,2,2-trimethyl-propyl)-6,7-dihydro-5H-pyrazolo[1,5-a]pyrazin-4-one

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Reaction Steps

A mixture of (R)-5-phenoxymethyl-2-[2-(1,2,2-trimethyl-propylamino)-ethyl]-2H-pyrazole-3-carboxylic acid (130 mg, 0.38 mmol) and HATU (143 mg, 0.38 mmol) in DMF (3 mL) was stirred for 5 minutes at room temperature, then DIPEA (0.16 mL, 0.945 mmol) were added. The reaction mixture was stirred at room temperature for 16 hours and then washed with a saturated solution of NH4Cl and extracted with DCM. The organic layer was separated, dried (Na2SO4), filtered and the solvents evaporated in vacuo. The residue was purified by flash column chromatography (silica; AcOEt in DCM 0/100 to 20/80). The desired fractions were collected and the solvents evaporated in vacuo. The desired product was triturated with diethyl ether to yield (R)-2-phenoxymethyl-5-(1,2,2-trimethyl-propyl)-6,7-dihydro-5H-pyrazolo[1,5-a]pyrazin-4-one (21 mg, 17% yield) as a white solid. 1H NMR (500 MHz, CDCl3) δ ppm 0.98 (s, 9H), 1.21 (d, J=7.2 Hz, 3H), 3.66-3.79 (m, 2H), 4.27-4.40 (m, 2H), 4.73 (q, J=7.2 Hz, 1H), 5.09 (s, 2H), 6.93 (s, 1H), 6.96 (t, J=7.4 Hz, 1H), 7.00 (d, J=7.8 Hz, 2H), 7.27-7.32 (m, 2H).

Provenance & Evidence