反应详情

A suspension of 6.5 g of the product of Step A in 500 ml of ethanol was refluxed with stirring for 2 hours and the resulting clear yellow solution was concentrated and cooled in a refrigerator. The mixture was filtered and then 3.70 g of white crystalline product was crystallized from ethanol to obtain ethyl 4,5-dihydro-4-oxoimidazo-[1,2-a]-quinoxaline-2-carboxylate in the form of shiny crystals melting at 292°-293° C.

1. temperaturewas refluxed
2. concentrationthe resulting clear yellow solution was concentrated
3. temperaturecooled in a refrigerator
4. filtrationThe mixture was filtered
5. custom3.70 g of white crystalline product was crystallized from ethanol