1889-02-7Relevant articles and documents
First Report on Crystal Engineering of Hg(II) Halides with Fully Substituted 3,4-Pyridinedicarboxamides: Generation of Two-Dimensional Coordination Polymers and Linear Zig-Zag Chains of Mercury Metal Ions
Rana, Love Karan,Sharma, Sanyog,Hundal, Geeta
, p. 92 - 107 (2016)
Two new ligands N,N,N′,N′-tetraisopropyl/tetraisobutyl-3,4-pyridinedicarboxamide L1-L2 and six of their Hg(II)X2 complexes (where X = Cl-, Br-, and I-) have been synthesized and characterized. Single crystal X-ray structures of three complexes of L1 (1-3) with HgCl2/Br2/I2 and two complexes of L2 (4-5) with HgCl2/Br2 show that these are two-dimensional (2D) coordination polymers, with three different (one new) topologies and five coordinated Hg(II) ions, in square pyramidal coordination. Complex 6, of L2 with HgI2, is a dimer with a four coordinated tetrahedral Hg(II) ion. The ligands behave as two- or three-connecting linkers for forming coordination polymers (CPs) but only one-connector in the dimer. Various types of hydrogen bonding and other noncovalent interactions have been calculated, analyzed, and discussed for all the complexes and the ligand L1. Although the large size and soft character of iodide coupled with the steric effects of large isobutyl groups are mainly responsible for a change in the primary structure of 6, a significant role of the semilocalized LP···π and C-H···O noncovalent interactions into this has also been found. The latter transform this dimer into a stable 2D hydrogen-bonded network instead of a coordination polymer. The unique halide bridged 2D structure of 1 forms one-dimensional zig-zag chains of metal ions owing to the mercurophilic interactions. Weaker interactions of the same kind further extend along the basic skeleton of 2D CP and are facilitated by LP···π, strong C-H···Cl and C-H···N(py) interactions.
Synthesis and Biological Evaluation of Oral Prodrugs Based on the Structure of Gemcitabine
Zhao, Cuirong,Xue, Xiaoxia,Li, Gang,Sun, Cuicui,Sun, Changjun,Qu, Xianjun,Li, Wenbao
experimental part, p. 479 - 488 (2012/10/07)
A series of oral prodrugs based on the structure of gemcitabine (2′,2′-difluorodeoxycytidine) were synthesised by introducing an amide group at the N4-position of the cytidine ring. A total of 16 compounds were obtained, and their chemical and biological characteristics were evaluated. The half-maximal inhibitory concentrations (IC50s) for most of these compounds were higher than that of gemcitabine in vitro. Compounds 5d and 5m, the representative compounds, were examined in terms of their physiological stabilities and pharmacokinetics. Compound 5d showed good stability in PBS and simulated intestinal fluid, and an analysis of its pharmacokinetics in mice suggested that the introduction of an amide group to gemcitabine could greatly improve its bioavailability. Further evaluation of compound 5din vivo showed that this compound possesses higher activity than gemcitabine against the growth of HepG2 human hepatocellular carcinoma cells and HCT-116 colon adenocarcinoma cells with less toxicity to animals. These results suggest that compound 5d could be further developed as a potential oral anticancer agent for clinical applications in which gemcitabine is currently used. A series of oral prodrugs based on the structure of gemcitabine were synthesized. Physiological and metabolic stabilities, pharmacokinetics and antitumor activities were evaluated for representative compounds.
