Trifluoroacetic acid → 1-[(4-Fluorophenyl)methyl]-5-[2-(methoxymethylamino)ethyl]-2-piperazinone

Participants

Reaction Steps

A solution of methyl N-{1-{[(tert-butoxycarbonyl)-(4-fluorobenzyl)amino]methyl}-3-[methoxy(methyl)amino]propyl}glycinate (1.63 g, 3.82 mmol) in CH2Cl2 (41 mL) was treated with TFA (12.6 mL) at 0° C. The mixture was stirred at ambient temperature under inert atmosphere for 2 h and then concentrated in vacuo. The resulting oil was suspended in water (46 mL) and treated, portion-wise, with solid K2CO3 (3.1 g). The reaction was heated to 100° C. for 30 min. After cooling to ambient temperature, the mixture was saturated with NaCl and extracted into CH2Cl2 three times. The combined organic layers were dried over Na2SO4 and concentrated in vacuo to yield the title compound as an orange oil. 1H NMR (400 MHz, CDCl3) δ 7.29-7.23 (m, 2H), 7.05-6.99 (m, 2H), 4.63 (d, J=14.8 Hz, 1H), 4.47 (d, J=14.8 Hz, 1H), 3.62 (dt, J=17.2, 38.8 Hz, 2H), 3.47 (s, 3H), 3.12-3.10 (m, 1H), 3.08-2.94 (m, 2H), 2.71-2.62 (m, 2H), 2.55 (s, 3H), 1.82 (br s, 1H), 1.63 (dd, J=6.4, 12.4 Hz, 2H). ES MS (M+1)=296.4.

Provenance & Evidence