Novel Bisphosphonates Derived from 1H-Indazole, 1H-Pyrazolo[3,4-b]Pyridine, and 1H-Pyrazolo[3,4-b]Quinoline

• Autor(a) principal: Teixeira, Fatima
• Data de Publicação: 2016
• Outros Autores: Lucas, Carla, Curto, Maria João Marcelo, Teixeira, António P. S., Duarte, M. Teresa, Andre, Vania
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.9/2867
• topic: Bisphosphonates; Indazole; Pyrazolo[3,4-b]pyridine; Pyrazolo[3,4-b]quinoline; Microwave-assisted reaction

Novel tetraethyl ethylene-1,1-bisphosphonate esters derived from 1H-indazole, 1H-pyrazolo[3,4-b]pyridine, and 1H-pyrazolo[3,4-b]quinoline were synthesized by a Michael addition reaction of tetraethyl ethylidene-1,1-bisphosphonate with the corresponding heterocycle, using conventional heating and microwave-assisted methods. The microwave-assisted method provides shorter reaction times and better yields. The hydrolysis of bisphosphonates afforded the corresponding bisphosphonic acids or salt, using concentrated hydrochloric acid or TMSBr/collidine, respectively. All new compounds were fully characterized, and their structures were assigned using 1H, 31P, and 13C NMR and IR spectroscopies and mass spectrometry. The molecular structure of compound 6 was confirmed by X-ray diffraction studies.