Formation of 3,N4-ethenocytidine, 1,N6-ethenoadenosine, and 1,N2-ethenoguanosine in reactions of mucochloric acid with nucleosides.

Mucochloric acid, a genotoxic hydroxyfuranone found in chlorinated drinking water, was reacted with cytidine, adenosine, guanosine, and uridine. HPLC analyses with UV detection at 290 nm showed that one major product peak was formed in the reactions of cytidine, adenosine, and guanosine. The products formed in reactions carried out at 90 degrees C for 24 or 45 h were isolated by HPLC and characterized by 1H and 13C NMR spectroscopy, direct inlet chemical ionization mass spectrometry, and UV absorbance spectroscopy. The structures of the products were assigned to 3,N4-ethenocytidine, 1,N6-ethenoadenosine, and 1,N2-ethenoguanosine. In reactions performed at 37 degrees C and pH 7.0 the same compounds were detected after a reaction time of 7 days. No observable reaction took place between mucochloric acid and uridine.