N,N′-Dimethylpropyleneurea (DMPU) is a cyclic urea sometimes used as a polar, aprotic organic solvent. In 1985, Dieter Seebach showed that it is possible to replace the suspected carcinogen hexamethylphosphoramide (HMPA) with DMPU.[2]
Anderson, J. C.; Smith, S. C. (1990). "Oxodiperoxymolybdenum(pyridine)-1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (MoO5 · Py · DMPU): A safer alternative to MoOPH for the α-hydroxylation of carbonyl compounds". Synlett. 1990 (2): 107–108. doi:10.1055/s-1990-21003.