A route to pyrazolylazopyrazolo[4,3-c]pyrazoles via l,5-dimethyl-3R-pyrazolyl-4-diazonium salts

l,5-Dimethyl-3R-pyrazolyl-4-diazonium salts (R = H, C ≡ C–Ph) have been converted into the corresponding 6-(l,5-dimethyl-3R-pyrazol-4-yl)azo-l-methyl-3R-4H-pyrazolo[4,3-c]pyrazoles 6a,b and it has been shown that the reaction proceeds via l-methyl-5-(l,5-dimethyl-3R-pyrazolyl-4-azo)methyl-3R-pyrazolyl-4-diazonium chlorides 4a,b.