Synthesis of novel pyrazolo[3,4-b]quinolinebisphosphonic acids and an unexpected intramolecular cyclization and phosphonylation reaction.

摘要: Novel pyrazolo[3,4-b]quinoline α-ketophosphonic and hydroxymethylenebisphosphonic acid compounds were synthesized using different methodologies, starting from 2-chloro-3-formylquinoline 1. New phosphonic obtained as N-1 derivatives with a side chain 1 or 3 (n = 3) methylene groups. All their corresponding ester carboxylic precursors fully characterized, structures elucidated by spectroscopic data, NMR techniques infrared high-resolution mass spectroscopy. During the process to obtain substituted derivative two groups 2) in chain, an unexpected addition–cyclization cascade reaction was observed, involving phosphonylation of aromatic ring formation new six-member lactam afford tetracyclic system. This result since other all pyrazolo[3,4-b]pyridine already prepared, under similar experimental conditions, did not undergo this reaction. domino occurs phosphite reagents but only affords ring. The data allowed identification X-ray diffraction compound 11 enabled confirmation proposed structures.