Ring-chain tautomerism of chlorinated hydroxyfuranones and reaction with nucleosides

Several genotoxic hydroxyfuranones present in chlorine disinfected drinking water, were reacted with adenosine, guanosine, and cytidine in aqueous solution. HPLC analyses with UV detection at 254 and 325 nm showed that adducts were formed. The compounds MCF, 3-chloro-4-methyl-5-hydroxy-2(5H)-furanone and mCMF, 4-(chloromethyl)-5-hydroxy-2(5H)-furanone tautomerized to the corresponding oxobutenoic acids at pH 7.4 and formed 4-(N ⁶-adenosinyl)-3-formyl-3-butenoic acid (I) as the major product. The hydroxyfuranone MX, 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone reacted with guanosine, and formed 10-formyl-1,N ²-benzoquinone propenoguanosine. The adducts were isolated by C18 column chromatography, and characterized by UV absorbance, ¹H spectroscopy, and mass spectrometry.