2-Benzoyl­pyridine semicarbazone

The title compound, C13H12N4O, crystallizes with two independent mol­ecules in the asymmetric unit. The compound crystallizes as the ZE isomer, where Z and E refer to the configuration around the C=N and N—C bonds, respectively, with an N—H⋯Npy (py is pyridine) intra­molecular hydrogen bond. The dihedral angles between the least-squares planes through the semicarbazone group and the pyridyl ring are 22.70 (9) and 27.26 (9)° for the two mol­ecules. There are intermolecular N—H⋯O hydrogen bonds

Nano-scale hydrogen-bond network improves the durability of greener cements

More than ever before, the world's increasing need for new infrastructure demands the construction of efficient, sustainable and durable buildings, requiring minimal climate-changing gas-generation in their production. Maintenance-free “greener” building materials made from blended cements have advantages over ordinary Portland cements, as they are cheaper, generate less carbon dioxide and are more durable. The key for the improved performance of blends (which substitute fine amorphous silicates for cement) is related to their resistance to water penetration. The mechanism of this water resistance is of great environmental and economical impact but is not yet understood due to the complexity of the cement's hydration reactions. Using neutron spectroscopy, we studied a blend where cement was replaced by ash from sugar cane residuals originating from agricultural waste. Our findings demonstrate that the development of a distinctive hydrogen bond network at the nano-scale is the key to the performance of these greener materials

8-Hydroxyquinoline Schiff-base Compounds as Antioxidants and Modulators of Copper-Mediated Aβ Peptide Aggregation

One of the hallmarks of Alzheimer\u27s disease (AD) in the brain are amyloid-β (Aβ) plaques, and metal ions such as copper(II) and zinc(II) have been shown to play a role in the aggregation and toxicity of the Aβ peptide, the major constituent of these extracellular aggregates. Metal binding agents can promote the disaggregation of Aβ plaques, and have shown promise as AD therapeutics. Herein, we describe the syntheses and characterization of an acetohydrazone (8-H2QH), a thiosemicarbazone (8-H2QT), and a semicarbazone (8-H2QS) derived from 8-hydroxyquinoline. The three compounds are shown to be neutral at pH 7.4, and are potent antioxidants as measured by a Trolox Equivalent Antioxidant Capacity (TEAC) assay. The ligands form complexes with CuII, 8-H2QT in a 1:1 metal:ligand ratio, and 8-H2QH and 8-H2QS in a 1:2 metal:ligand ratio. A preliminary aggregation inhibition assay using the Aβ1–40 peptide showed that 8-H2QS and 8-H2QH inhibit peptide aggregation in the presence of CuII. Native gel electrophoresis/Western blot and TEM images were obtained to give a more detailed picture of the extent and pathways of Aβ aggregation using the more neurotoxic Aβ1 −42 in the presence and absence of CuII, 8-H2QH, 8-H2QS and the drug candidate PBT2. An increase in the formation of oligomeric species is evident in the presence of CuII. However, in the presence of ligands and CuII, the results match those for the peptide alone, suggesting that the ligands function by sequestering CuII and limiting oligomer formation in this assay

Analgesic and anti-inflammatory activities of salicylaldehyde 2-chlorobenzoyl hydrazone (H2LASSBio-466), salicylaldehyde 4-chlorobenzoyl hydrazone (H 2LASSBio-1064) and their zinc(II) complexes

Salicylaldehyde 2-chlorobenzoyl hydrazone (H 2LASSBio-466), salicylaldehyde 4-chlorobenzoyl hydrazone (H 2LASSBio-1064) and their complexes [Zn(LASSBio- 466)H 2O] 2 (1) and [Zn(HLASSBio-1064)Cl] 2 (2) were evaluated in animal models of peripheral and central nociception, and acute inflammation. All studied compounds significantly inhibited acetic acid-induced writhing response. Upon coordination the antinociceptive activity was favored in the complex 1. H 2LASSBio-466 inhibited only the first phase of the formalin test, while 1 was active in the second phase, like indomethacin, indicating its ability to inhibit nociception associated with the inflammatory response. Hence coordination to zinc(II) altered the pharmacological profile of H 2LASSBio-466. H2LASSBio-1064 inhibited both phases but this effect was not improved by coordination. The studied compounds did not increase the latency of response in the hot plate model, indicating their lack of central anti-nociceptive activity. All compounds showed levels of inhibition of zymosan-induced peritonitis comparable or superior to indomethacin, indicating an expressive anti-inflammatory profile.Facultad de Ciencias Exacta