Open AccessNovel Bisphosphonates Derived from 1 H ‐Indazole, 1 H ‐Pyrazolo[3,4‐ b ]Pyridine, and 1 H ‐Pyrazolo[3,4‐ b ]Quinoline
Author(s) -
Teixeira Fátima C.,
Lucas Carla,
Curto M. João M.,
Teixeira António P. S.,
Duarte M. Teresa,
André Vânia
Publication year - 2016
Publication title -
heteroatom chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.283
H-Index - 42
eISSN - 1098-1071
pISSN - 1042-7163
DOI - 10.1002/hc.21282
Subject(s) - chemistry , quinoline , indazole , pyridine , medicinal chemistry , hydrochloric acid , hydrolysis , nuclear chemistry , organic chemistry
Novel tetraethyl ethylene‐1,1‐bisphosphonate esters derived from 1 H ‐indazole, 1 H ‐pyrazolo[3,4‐ b ]pyridine, and 1 H ‐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 1 H, 31 P, and 13 C NMR and IR spectroscopies and mass spectrometry. The molecular structure of compound 6 was confirmed by X‐ray diffraction studies.