Urea → HCID 58089233, compound

Participants

Reaction Steps

18 g compound 19 (86 mmole), 20.8 g ureum (346 mmole) and 5 drops polyphosphoric acid were heated at 150° C. during 18 h. After cooling, 500 ml EtOAc was added and the resulting solution was washed twice with brine. After evaporation of the organic phase, the resulting residue was purified by flash chromatography (Acros Silicagel 0.060-0.200 mm) using cyclohexane/isopropanol 95:5, affording compound 20 as a white powder (9.17 g, 51% yield).

Provenance & Evidence