Condensation of trieformylmethane with guanosine

Guanosine has been reacted with triformylmethane (TFM) in refluxing pyridin e. Four different products, 4-7, were isolated by preparative RP-HPLC, and characterized by H-1 and C-13 NMR and UV spectroscopy and mass spectrometry . One of the products, the cyclic 1:1 adduct 4, is a stable cyclic carbinol amine formed probably by cyclization of the expected aminomethylene derivat ive 3. Compound 4 then undergoes reversible dehydration to the fully conjug ated adduct 5. The appearance of the additional adducts, 6 and 7, suggests that TFM is prone to transformations resulting in the formation of methylen emalonaldehyde (9) and 1,1,3,3-tetraformylpropane (11).