1,4-Cyclohexadiene → HCID 131717662, compound

Participants

Reaction Steps

To a flask containing 10% palladium on carbon (2.11 g) under nitrogen was added [3-[[2-(diethoxyphosphinyl)ethyl](2-ethoxy-3,4-dioxo-1cyclobuten-1-yl)amino]propyl]carbamic acid phenylmethyl ester (2.11 g, 4.2 mmol) in absolute ethanol (180 mL), followed by 1,4-cyclohexadiene (4.3 mL, 45 mmol). After stirring for 5 hours, the reaction mixture was filtered through Celite® and concentrated in vacuo to yield a crude solid, which was recrystallized from methanol and ethyl acetate (total volume=20 mL), filtered, and washed with hexane to afford [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid diethyl ester hemihydrate as a cream colored solid (0.82 g, 62%, mp 148°-149° C.); IR (KBr, cm-1): 1810; 1H NMR (CDCl3, 400 MHz): δ 7.50 (br s, NH), 4.18-4.10 (m, 4H), 4.09-4.00 (m, 2H), 3.51-3.46 (m, 4H), 2.19 (d of t, J=18 and 7.5 Hz, 2H), 2.10-2.04 (m, 2H), 1.34 (t, J=7 Hz, 6H).

Provenance & Evidence