Isolation of a MX-guanosine adduct formed at physiological conditions.

3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a highly potent mutagen present in chlorine-disinfected drinking water, was allowed to react with adenosine, guanosine, and cytidine in aqueous solutions. HPLC analyses, with detection at 254 and 310 nm, showed that a clearly detectable base adduct was formed in the reaction with guanosine. This substance was isolated by C18 column chromatography and characterized by UV absorbance, 1H NMR spectroscopy, and mass spectrometry. The compound was identified as 10-formyl-1, N2-benzoquinone propenoguanosine (I), and the yield was estimated to be approximately 0.1% in reactions performed at pH 7.4 and 37 degrees C.