Fm. Abd El Latif et al., New routes for novel pyrazolo[3,4-b][1,6]-naphthyridine, pyrazolo[3,4-b]pyridine and pyrazolo[3,4 : 2,3]pyrido[6,1-a]benzimidazole derivatives, J CHEM R-S, (12), 1999, pp. 696-697A
Pyrazolo[3,4-6] [1,6]naphthyridine, pyrazolo[3,4-b] pyridine and pyrazolo[3
,4:2,3] pyrido[6,1-a] benzimidazole derivatives are synthesized starting fr
om the isomeric 3-substituted 5-chloro-1-phenylpyrazole-4-carbaldehyde.