Diisopropylethylamine → 3-{2-[8,9-Dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl]ethyl}-3-oxido-7-oxo-8-propyl-2,4,6-trioxa-3-phosphaundec-1-yl 2-propylpentanoate

Participants

Reaction Conditions

Reaction Steps

A solution of the starting [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)ethyl]phosphonic acid (26 mmol, 6.765 g) in dry DMF (250 mL) was treated with N,N-diisopropylethylamine (104 mmol, 13.442 g) followed by 2-propyl-pentanoic acid chloromethyl ester (88 mmol, 17 g, synthesis described below) at ambient temperature and under exclusion of moisture. The reaction mixture was heated to 65° C. and held, with stirring, at 65° C. for over 16 hours. The solvent was removed by vacuum distillation and the residue was partitioned (2×) between water and ether. The organic phase was separated, dried over magnesium sulfate, filtered, and evaporated to dryness affording about 16 g of crude product as a dense yellow oil. This oil was flash chromatographed on 350 g silica gel. Elution with 8% methanol/ethyl acetate afforded 8.4 g (56%) of the desired product as a colorless solidified wax. MS (ES+): m/e 573 (M+H).

Provenance & Evidence