O-Succinimidyl-1,3-dimethyl-1,3-trimethyleneuronium salts as efficient reagents in active ester synthesis

The new uronium salts O-succinimidyl-1,3-dimethyl-1,3-trimethyleneuronium hexafluorophosphate (HSDU) and tetrafluoroborate (TSDU) have been prepared from 1,3-dimethylpropyleneurea (DMPU) and employed in the synthesis of N-hydroxysuccinimide-derived active esters. High yields were obtained at room temperature in short reaction times and no racemization was observed.