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- New indazole and condensed pyrazole bisphosphonatesPublication . Teixeira, Fatima; Lucas, Carla; Antunes, Inês F.; Curto, Maria João Marcelo; Duarte, M. Teresa; Andre, Vania
- New 1-Hydroxy-1,1-bisphosphonates derived from 1H-Pyrazolo[3,4-b]pyridine: Synthesis and CharacterizationPublication . Teixeira, Fatima; Lucas, Carla; Curto, Maria João Marcelo; Neves, M.; Duarte, M. Teresa; Andre, Vania; Teixeira, António P. S.A number of 1H-pyrazolo[3,4-b]pyridine derivatives, starting from 2-chloro-3-formyl pyridine, was synthesized to obtain new 1-hydroxybisphosphonates, a class of compounds with potential biological interest. Spectroscopic data were used to characterize all compounds and to identify N-1 and N-2 regioisomers, and mono- and bisphosphonates derivatives. X-ray diffractometry studies of compound 7a confirmed the proposed structure.
- Novel Bisphosphonates Derived from 1H-Indazole, 1H-Pyrazolo[3,4-b]Pyridine, and 1H-Pyrazolo[3,4-b]QuinolinePublication . Teixeira, Fatima; Lucas, Carla; Curto, Maria João Marcelo; Teixeira, António P. S.; Duarte, M. Teresa; Andre, VaniaNovel 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.
- Synthesis and characterization of novel hydroxy- and aminobisphosphonatesPublication . Teixeira, Fatima; Lucas, Carla; Pereira, Inês F. A.; Curto, Maria João Marcelo; Neves, M.; Duarte, M. TeresaBisphosphonates (BPs) are a family of drugs that are successfully used in the treatment of various calcium-related disorders such as Pagetμs disease, osteoporosis and bone metastases. In addition, functional BPs have been also used in the treatment of metal intoxication and as novel ligands for well-defined radioactive metal complexes that can be used in imagiology, scintigraphy and radiotherapy applications [1,2]. The indazole derivatives are pharmacologically important compounds and the indazole ring system forms the basis of a number of drug molecules. Condensed pyrazoles are also known as pharmacophoric elements in numerous active compounds. However, in comparison with other heteroaromatic compounds, the chemistry of indazole and condensed pyrazoles remains less studied [3]. The present work is to extend the previous studies in indazolebisphosphonates [4] in order to obtain new BPs derived from indazole and condensed pyrazole with potential biological/therapeutical activities. Herein, we report the synthesis and characterization of a series of new 1-hydroxybisphosphonates (1) and aminobisphosphonates (2) (substituted at different C- or N-positions of the indazole ring - N-1, C-5, C-6, C-7)
- New substituted indazole and condensed pyrazole bisphosphonetesPublication . Teixeira, Fatima; Lucas, Carla; Curto, Maria João Marcelo; Neves, M.; Duarte, M. Teresa; Andre, Vania