Synthesis and evaluation of novel heterocyclic MMP inhibitors

2-(1,2,3-Triazol-4-yl)-imidazoline, -oxazoline, -thiazoline and -tetrahydropyrimidine as ligands in copper(II) and nickel(II) complexes

2-(1-Benzyl-1H-1,2,3-triazol-4-yl)-imidazolines (L1 and L2/L2′), -1,3-oxazoline (L3), -1,3-thiazoline (L4) and -tetrahydropyrimidine (L5) were prepared in one step from a 1,2,3-triazole-4-carboxamidinium tetraphenylborate and studied as novel ligands for copper(II) and nickel(II) ions. The solid-state structures of the following complexes were established: [Cu(L1)2](OTf)2, [CuL2L2′(OTf)2] · 2H2O, [[Cu(L4)2(H2O)2](OTf)2 · [Cu(L4)2(OTf)2], [Cu(L5)2(OTf)2], Cu(L3)2Cl2] · THF, [Ni(L1)2Cl2].

Synthesis and antibacterial activities of acylide derivatives bearing an aryl-tetrazolyl chain

Seventeen acylides bearing an aryl-tetrazolyl alkyl-substituted side chain were synthesized, starting from clarithromycin, via several reactions including hydrolysis, acetylating, esterification, carbamylation, and Michael addition. The structures of all new compounds were confirmed by ¹H nuclear magnetic resonance spectroscopy, ¹³C nuclear magnetic resonance spectroscopy, and mass spectrometry. All these synthesized acylides were evaluated for in vitro antimicrobial activities against gram-positive pathogens (Staphylococcus aureus, Staphylococcus epidermidis) and gram-negative pathogens (Pseudomonas aeruginosa, Escherichia coli), using the broth microdilution method. Results showed that compounds 10e, 10f, 10g, 10 h, 10o have good antibacterial activities.

D-penicillamine and other low molecular weight thiols: review of anticancer effects and related mechanisms

Low molecular weight thiols (LMWTs) like N-acetyl cysteine, D-penicillamine, captopril, Disulfiram and Amifostine, etc. have been used as chemo-preventive agents. Recent studies have reported cell growth inhibition and cytotoxicity in several different types of cancer cells following treatment with several LMWTs. Cytotoxic and cytostatic effects of LMWTs may involve interaction of the thiol group with cellular lipids, proteins, intermediates or enzymes. Some of the mechanisms that have been proposed include a p53 mediated apoptosis, thiyl radical induced DNA damage, membrane damage through lipid peroxidation, anti-angiogenic effects induced by inhibition of matrix metalloproteinase enzymes and angiostatin generation. LMWTs are strong chelators of transition metals like copper, nickel, zinc, iron and cobalt and may cause metal co-factor depletion resulting in cytotoxicity. Oxidation of thiol group can also generate cytotoxic reactive oxygen species (ROS).

Asymmetric polymerizations of chiral 4-benzyl-2-ethynyloxazoline with rhodium catalyst and chiroptical properties of the polymers

Optically active 4-alkyl-2-ethynyloxazoline derivatives (BnEOx) were polymerized with rhodium catalysts. The polymerization in toluene produced polymer with the highest absolute values of specific rotation ([α](D) = -77.3°). The yields, molecular weights, and specific rotations of poly(BnEOx)s were influenced by polymerization conditions. The copolymerization with phenylacetylene (PA) was effective to increase the molecular weight of the copolymer. It is interesting to note that the copolymers exhibited positive specific rotations ([α](D) = +4.7° to +62.5°) despite the fact that [α](D) s of BnEOx and the homopolymer are negative sign. The chiroptical properties were investigated by the chiral/achiral copolymerization of BnEOx with PA. The copolymerizations of BnEOx with PA gave copolymers containing higher order structure such as one-handed helical conformation. Furthermore, induced Cotton effects were observed in the π-π* transition region of conjugated main chain depending a complex of these polymers with zinc triflate salt in tetrahydrofuran solution, indicating the formation of chiral supramolecular aggregates.

A macrophage cell model for selective metalloproteinase inhibitor design

The desire to inhibit zinc-dependent matrix metalloproteinases (MMPs) has, over the course of the last 30 years, led to the development of a plethora of MMP inhibitors that bind directly to the active-site metal. With one exception, all of these drugs have failed in clinical trials, due to many factors, including an apparent lack of specificity for MMPs. To address the question of whether these inhibitors are selective for MMPs in a biological setting, a cell-based screening method is presented to compare the relative activities of zinc, heme iron, and non-heme iron enzymes in the presence of these compounds using the RAW264.7 macrophage cell line. We screened nine different zinc-binding groups (ZBGs), four established MMP inhibitors (MMPis), and two novel MMP inhibitors developed in our laboratory to determine their selectivities against five different metalloenzymes. Using this model, we identified two nitrogen donor compounds--2,2'-dipyridylamine (DPA) and triazacyclononane (TACN)--as the most selective ZBGs for zinc metalloenzyme inhibitor development. We also demonstrated that the model could predict known nonspecific interactions of some of the most commonly used MMPis, and could also give cross-reactivity information for newly developed MMPis. This work demonstrates the utility of cell-based assays in both the design and the screening of novel metalloenzyme inhibitors.