- Syntheses, structures and catalytic activities of two cyclopalladated complexes derived from N'-(2-naphthylidene)benzohydrazide
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Condensation reaction of 2-naphthaldehyde with one equivalent of benzohydrazide in presence of acetic acid in refluxing methanol yielded the Schiff base N'-(2-naphthylidene)benzohydrazide (H2L) in 86% yield. Reaction of equimolar amounts of Li2PdCl4 (generated in situ from PdCl2 and LiCl taken in 1:2 mol ratio), H2L and NaOAc·3H2O in methanol at room temperature provided the complex [Pd(HL)Cl] (1) in 82% yield. Treatment of 1 mol equivalent of 1 with 2 mol equivalents of PPh3 in acetone at room temperature produced the complex [Pd(L)(PPh3)] (2) in 72% yield. The Schiff base and the two complexes were characterized by elemental analysis, mass spectrometric and various spectroscopic (IR, UV–Vis and 1H NMR) measurements. The molecular structures of both complexes (1 and 2) were determined by single crystal X-ray crystallography. In each square-planar complex, the tridentate ligand (HL? in 1 and L2? in 2) acts as pincer-like CNO-donor. The fourth coordination site is occupied by chloride in 1, while that in 2 is satisfied by the P-atom of PPh3. The 2-naphthyl fragment of both HL? and L2? is palladated at the 3-position. Complex 2 was found to be an effective catalyst for one-pot Suzuki-Miyaura double cross-coupling reactions of 3,5-dihalosalicylaldehydes with a variety of arylboronic acids to provide the corresponding triaryl products in moderate to excellent yields.
- Babu, G. Narendra,Rao, A.R. Balavardhana,Keesara, Srinivas,Pal, Samudranil
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p. 243 - 248
(2017/08/23)
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- N-(1'-naphthyl)-3,4,5-trimethoxybenzohydrazide as microtubule destabilizer: Synthesis, cytotoxicity, inhibition of cell migration and in vivo activity against acute lymphoblastic leukemia
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Tubulin-interacting agents, like vinca alkaloid and taxanes, play a fundamental role in cancer chemotherapy, making cellular microtubules (MT), one of the few validated anticancer targets. Cancer resistance to classical MT inhibitors has motivated the development of novel molecules with increased efficacy and lower toxicity. Aiming at designing structurally-simple inhibitors of MT assembly, we synthesized a series of thirty-one 3,4,5-trimethoxy-hydrazones and twenty-five derivatives or analogs. Docking simulations suggested that a representative N-acylhydrazone could adopt an appropriate stereochemistry inside the colchicine-binding domain of tubulin. Several of these compounds showed anti-leukemia effects in the nanomolar concentration range. Interference with MT polymerization was validated by the compounds' ability to inhibit MT assembly at the biochemical and cellular level. Selective toxicity investigations done with the most potent compound, a 3,4,5-trimethoxy-hydrazone with a 1-naphthyl group, showed remarkably selective toxicity against leukemia cells in comparison with stimulated normal lymphocytes, and no acute toxicity in vivo. Finally, this molecule was as active as vincristine in a murine model of human acute lymphoblastic leukemia at a weekly dose of 1 mg/kg.
- Salum, Lívia B.,Mascarello, Alessandra,Canevarolo, Rafael R.,Altei, Wanessa F.,Laranjeira, Angelo B.A.,Neuenfeldt, Patrícia D.,Stumpf, Taisa R.,Chiaradia-Delatorre, Louise D.,Vollmer, Laura L.,Daghestani, Hikmat N.,De Souza Melo, Carolina P.,Silveira, André B.,Leal, Paulo C.,Frederico, Marisa J.S.,Do Nascimento, Leandro F.,Santos, Adair R.S.,Andricopulo, Adriano D.,Day, Billy W.,Yunes, Rosendo A.,Vogt, Andreas,Yunes, José A.,Nunes, Ricardo J.
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p. 504 - 518
(2015/05/13)
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- Electrosynthesis and screening of novel 1,3,4-oxadiazoles as potent and selective antifungal agents
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The electrochemical oxidation of aldehyde-N-aroylhydrazone has been studied in the presence of NaClO4 as supporting electrolyte in MeOH solution using cyclic voltammetry and controlled potential electrolysis. The results indicate that intramolecular cyclization of aldehyde-N-aroylhydrazone has been successfully performed at a platinum electrode in an undivided cell with good yields of the corresponding 1,3,4-oxadiazoles at ambient conditions. The reaction products were characterized by spectroscopic methods and a mechanism was deduced from voltammetry studies. The antifungal activity of the synthesized compounds was evaluated on Fusarium oxysporum, Alternaria solani, Candida albicans and Aspergillus niger. The results revealed that all the synthesized compounds have significant antifungal activity against the tested fungi. Among the synthesized derivatives 7b, 7d, 7g, 7h, 7i, 7j and 7r were found to be the most effective antifungal compounds. The Royal Society of Chemistry 2013.
- Singh, Sushma,Sharma, Laxmi Kant,Saraswat, Apoorv,Siddiqui, Ibadur R.,Kehri, Harbans K.,Singh, Rana K. Pal
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p. 4237 - 4245
(2013/05/08)
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- Solvent-free synthesis of hydrazones and their subsequent N-alkylation in a Ball-mill
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A large variety of Boc-, Bz-, Ts-, and Fmoc- protected hydrazones were prepared via condensation of an equimolar amount of carbonyl-compound and the corresponding hydrazine using a ball-mill. Hydrazones were always obtained in a quantitative yield and no solvents were used at any step. In a second step, we realized the first solvent-free N-allylation and N-benzylation of these hydrazones.
- Nun, Pierrick,Martin, Charlotte,Martinez, Jean,Lamaty, Frédéric
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supporting information; experimental part
p. 8187 - 8194
(2011/10/31)
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