Author(s): Teixeira, António P. S. ; Teixeira, Fátima C. ; Lucas, Carla ; Curto, M. João M. ; Duarte, M. Teresa ; André, Vânia
Date: 2016
Persistent ID: http://hdl.handle.net/10174/17161
Origin: Repositório Científico da Universidade de Évora
Subject(s): Bisphosphonate; 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-yrazolo[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.
