4-Hydroxy-2-methylisoquinolinium iodide

Treatment of the pyrazolium[4,3-r/][l,2,3]oxadiazolium diiodide 124 with -hydroxy- or /)-dimethylaminobenzalde-hyde yielded the pyrazolo[4,3-r/][l,2,3]oxadiazole styryl and azastyryl cyanines 83a and 83b in modest yields. Parallel reaction with -nitrosophenol furnished 83c. Reaction of 124 with 1-ethylquinolinium iodide afforded 84a directly. However, 3-anilinocarbomylmethyl-2,4-diethyl-(N-phenylcarbomylmethyl)pyrazolium(4,3-r/)[l,2,3]oxadiazolium diiodide 125 arising from reaction of 124 with diphenylformamidine in refluxing acetic anhydride, is the precursor to 84b which follows from subsequent reaction with 2-methylisoquinolinium iodide (Scheme 16) <1994MI905-1>. 

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