Hydrochloric Acid → Azepane-2,4-dione

Participants

Reaction Steps

A solution of 10% aqueous HCl (17 mL) was added to an acetone solution (70 mL) of the 4-ethoxy-6,7-dihydro-1H-azepin-2(5H)-one (2.5 g, 16 mmol) from Example 1 at 25° C. The reaction mixture was stirred for 12 hours. The acetone was removed in vacuo, and the resulting mixture was extracted with CH2Cl2 (10×15 mL). The combined organic extracts were dried (Na2SO4), filtered, and concentrated in vacuo to afforded the crude product as a yellow solid. Purification by flash column chromatography (silica, 10% MeOH/EtOAc) afforded azepane-2,4-dione (2.03 g, 100%) as a white solid: 1H NMR (400 MHz, CDCl3) d 7.55 (s, NH), 3.47 (s, 2H), 3.40 (m,), 2.59 (t, J=6.8 Hz, 2H), 1.96 (m, 2H); 13C NMR (100 MHz, CDCl3) d 202.5, 169.5, 51.9, 43.2, 40.8, 27.6; IR (KBr) nmax 3213, 3105, 2942, 1702, 1671, 1482, 1412, 1348 cm−1; HRMS (ESI) m/z calcd for C6H9NO2Na: 150.0525. found: 150.0507.

Provenance & Evidence