1-Isopropylpiperazine → 1-(4-methoxybenzyl)-7-(3-(4-isopropylpiperazin-1-yl)azetidin-1-yl)-1,5-naphthyridin-2(1H)-one

Participants

Reaction Steps

A mixture of 1-(4-methoxybenzyl)-7-(3-oxoazetidin-1-yl)-1,5-naphthyridin-2(1H)-one (C-7) (5.796 g, 17.3 mmol, 1.0 eq) and 1-isopropylpiperazine (4.432 g, 34.6 mmol, 2.0 eq) in DCM (150 mL) and acetic acid (0.5 mL) was heated at reflux temperature for 3 h, then NaBH(OAc)3 (7.33 g, 34.6 mmol, 2.0 eq) was added in portions and the resulting mixture was kept reflux overnight. The reactant mixture was cooled and diluted with H2O (300 mL) and extracted with DCM (4×100 mL). The combined organic layers were washed with brine, dried over Na2SO4 and filtered. The filtrate was concentrated in vacuo and the residue was purified by flash column chromatography on silica gel (2-5% MeOH-DCM) to afford the desired product 1-(4-methoxybenzyl)-7-(3-(4-isopropylpiperazin-1-yl)azetidin-1-yl)-1,5-naphthyridin-2(1H)-one (C-8) (5.6 g, 72.3% yield) as a pale solid. 1H NMR (300 MHz, CDCl3-d6) δ: 7.83 (d, J=7.5 Hz, 1H), 7.78 (s, 1H), 7.15 (d, J=6.9 Hz, 2H), 6.85 (d, J=6.6 Hz, 2H), 6.72 (d, J=7.2 Hz, 1H), 6.37 (s, 1H), 5.40 (s, 2H), 4.02 (m, 2H), 3.78 (m, 5H), 3.67 (m, 1H), 3.51 (m, 1H), 3.42 (m, 1H), 2.97 (m, 1H), 2.80 (m, 4H), 2.55 (m, 2H), 1.17 (d, J=4.8 Hz, 6H); ESI-MS m/z: 448.3 [M+H]+.

Provenance & Evidence