Purines, pyrimidines, and condensed systems based on them. 17. Reactions of 6,8-dimethyl-3-chloropyrimido-[4,5-c]pyridazin-5,7(6H,8H)dione with C-nucleophiles
Abstract6,8-Dimethyl-3-chloropyrimido-[4,5-c]pyridazin-5,7(6H,8H)dione reacts with malonodinitrile, cyanoacetic ester, and nitromethane in the presence of bases to give products of nucleophilic substitution of the chlorine atom. The products containing the cyanoacetic ester and nitromethane residues exist exclusively in the chelated methylidene form in CHCl3 and DMSO solutions. Reactions of pyridazinouracil with methylmagnesium chloride and butyllithium gave products of nucleophilic addition at C(4).