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 substitute the relatively toxic hexamethylphosphoramide (HMPA) with DMPU. 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 substitute the relatively toxic hexamethylphosphoramide (HMPA) with DMPU.