Diisopropylethylamine → 7-Benzyl-hexahydro-oxazolo[3,4-a]pyrazin-3-one

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of (4-benzyl-piperazin-2-yl)methanol (250 mg, 1.21 mmol) in anhydrous DCE (8.0 mL) was added triphosgene (133 mg, 0.45 mmol, 0.37 eq) followed by diisopropylethylamine (0.25 mL, 1.45 mmol, 1.2 eq). The mixture was stirred at 50° C. under N2 for 16 h. The mixture was cooled to rt, quenched with aqueous, saturated NH4Cl solution (2.0 mL), and poured into EtOAc. The organic phase was washed with water and brine, dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by MPLC (Biotage®, gradient elution 80 to 100% EtOAc/hexane) to give the product (91.2 mg, 32%) as a clear oil, 1H-NMR (300 MHz, CD3OD) 7.35 to 7.24 (m, 5H), 4.38 (t, 1H), 3.96 to 3.87 (m, 2H), 3.71 to 3.66 (m, 1H), 3.57 (q, 2H), 3.14 to 3.07 (m, 1H), 2.97 to 2.93 (m, 2H), 2.04 (dt, 1H), 1.93 (t, 1H); ES-MS m/z 233.2 [M+H]+, RT (min) 0.29.

Provenance & Evidence