A green synthesis of glycoluril derivatives in aqueous solution with recycle of the waste

A series of glycoluril derivatives have been synthesized in water at room temperature from urea and 1,2- dicarbonyl compounds in the presence of phosphoric anhydride. The reaction time is about 10 minutes using one mole of 1,2-dicarbonyl compound, three moles of urea, and half mole of P4O10, but the reaction occurs also, even if with longer reaction times, with very small amounts of P4O10 which is recovered at the end of reactions. In fact, several catalytic turnovers can be performed using the same reaction solution obtained after separation by simple filtration of the glycolurils.