N-((5-Oxo-4,5-dihydro-1,2,4-triazin-6-yl)methyl)cyclobutanecarboxamide → 7-cyclobutyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one

Participants

Reaction Conditions

Reaction Steps

A crude solution of cyclobutanecarboxylic acid (5-oxo-4,5-dihydro-[1,2,4]triazin-6-ylmethyl)-amide (1.33 g, 6.39 mmol) in phosphorus oxychloride (POCl3) (10 mL) was heated to 55° C. The reaction was heated for 2 h then concentrated in vacuo and the crude oil was cooled to 0° C. in an ice-bath and quenched with 2 M NH3 in isopropanol (IPA) until slightly basic. This crude reaction mixture was concentrated in vacuo and was partitioned between DCM and H2O and separated. The aqueous layer was extracted with DCM (3×) and the combined organic fractions were dried over sodium sulfate (Na2SO4), filtered and concentrated in vacuo. The crude material was purified by chromatography on silica gel [eluting with 5% MeOH in DCM], resulting in the title compound as an off-white solid; 1H NMR (DMSO-d, 400 MHz) δ 1.86-1.96 (m, 1H), 2.00-2.13 (m, 1H); 2.26-2.46 (m, 4H); 3.87-4.00 (m, 1H); 7.71 (s, 1H); 7.87 (d, J=3.6 Hz, 1H); 11.7 (brs, 1H); MS (ES+): m/z 191.27 (100) [MH+], HPLC: tR=2.06 min (MicromassZQ, polar—5 min).

Provenance & Evidence