Synthesis and metallochromic properties of some new mono- and bishydrazones of benzil and 2,2'-pyridil

Preparation of some new mono- and bishydrazones which possess the ferroin chromophoric group is described, together with results of spectrophotometric studies of their chelation reactions with iron(II), copper(I), cobalt(II), nickel(II) and zinc(II). Several of the new compounds show promise as chromogenic reagents for these metals. The results are also of interest with regard to structure-reaction relationships.     

Synthesis and metallochromic properties of some hydrazones of 2-, 3- and 8-hydrazinoquinoline

Twenty-two new hydrazones were synthesized for evaluation as possible calorimetric reagents for trace determinations of iron, cobalt, nickel, copper and zinc. Spectrophotometric studies revealed that several show promise as sensitive reagents, with possible utility for simultaneous determinations of two or more of the metals. Conclusions regarding geometric structures of some of the hydrazones and chelates were deduced from mole-ratio studies.     

Synthesis and properties of some new polyazomethine-urethanes

Two new bisazomethine diols were prepared from terephthalaldehyde and aromatic or aliphatic aminoalcohols. The structure of the diols with bisazomethine moieties was confirmed by ¹H-NMR, IR, UV spectroscopy and elemental analysis. Bisazomethine aliphatic diol exhibited a smectic phase that has been identified by means of polarizing microscopy and differential scanning calorimetry. By using these diols as partners in polyaddition reaction between poly(tetramethylene oxide)diol of 2000 average molecular weight, tolylene-2,4-diisocyanate (as 2,4- and 2,6-TDI, 80:20 v/v isomers mixture) and bisazomethine diol (1:3:2 molar ratio), two polyazomethine-urethanes were synthesized. Polyazomethine-urethanes with a higher concentration of poly-Schiff's base units were also obtained by reacting the above bisazomethine diols with the same diisocyanate (1:1 molar ratio). All polymers were characterized by viscometry, elemental analysis, IR, UV, ¹H-NMR spectroscopy and TGA techniques.     

Synthesis of some new pyrimidine derivatives and evaluation of their anticancer and antibacterial activities

Starting from the reaction of ethyl cyanoacetate with thiourea and the appropriate aldehydes, a series of new pyrimidine derivatives were prepared. Ten selected pyrimidine derivatives were subjected to a screening system for the investigation of their antitumor potency against liver (HEPG2) cell line. The antitumor activity results indicated that most of the selected pyrimidine derivatives showed moderate growth inhibition activity against the tested cell line, but with varying intensities in comparison to the known anticancer drugs: 5-fluorouracil and doxorubicin. Some of the synthesized compounds were also tested for their antimicrobial activity against bacteria as well as fungal isolates.     

Synthesis,physicochemical properties and voltammetric characterization of some new Fe(III) complexes with semicarbazone-based ligands

Several bis(ligand) octahedral complexes of iron(III) with salicylaldehyde semi-, thiosemi-, and S-methylthiosemi- carbazones have been synthesized and characterized by elemental analysis, conductivity and magnetic measurements, electronic and IR spectra, as well as by linear sweep and cyclic voltammetry. General procedures for the syntheses of all types of complexes have been established, giving better defined reaction conditions. Physicochemical properties of the novel complexes have been related to those of the already known compounds of the same type.     

Synthesis of new derivatized pyrazole based ligands and their catecholase activity studies

A synthesis of three new tripodal ligands: 3-[bis-(3,5-dimethyl-pyrazol-1-ylmethyl)-amino]-propan-1-ol L1, 3-[bis-(5-methyl-3-carbomethoxy-pyrazol-1-ylmethyl)-amino]-propan-1-ol, L2 and 3-[bis-(5-methyl-3-carboethoxy-pyrazol-1-ylmethyl)-amino]-propan-1-ol L3 is reported. The in situ-generated copper(II) complexes of three new compounds (L1–L3) were examined for their catalytic activities and were found to catalyse the oxidation reaction of catechol to o-quinone with the atmospheric dioxygen. These activities depend on the nature of the ligand and the copper salts.     

Synthesis,structure and some properties of a new polyalcohol

A new polyalcohol (CH₂CH₂CH(OH))_n was synthesized from 1:1 ethylene/carbon monoxide alternating copolymer (polyketone) by reduction with sodium borohydride. Some structural and chemical properties are described.     

Complexes of some platinum group metals with hydrazone ligands and their catalytic oxidative properties

Summary New complexes of ruthenium(II), ruthenium(III), osmium(III) and palladium(II) have been prepared with a neutral bidendate hydrazone ligand derived from antipyrine-4-carboxaldehyde and benzoylhydrazine. Ruthenium(III) complexes have also been synthesized from monobasic bidendate ligands prepared from benzaldehyde and benzoyl orp-substituted (Me, Cl) benzoyl hydrazine. The complexes were characterized by spectroscopic techniques and investigated by cyclic voltammetry. The efficient catalytic oxidation of alcohols and 3,5-di- ^t butyl catechol in the presence of N-methylmorpholine-N-oxide orm-chloroperbenzoic acid as co-oxidants is reported.

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Komplexe einiger Platinmetalle mit Hydrazonliganden und ihre katalytischen oxidativen Eigenschaften

Zusammenfassung Neue Komplexe von Ru(II), Ru(III), Os(III) und Pd(II) mit einem aus Antipyrin-4-carbaldehyd und Benzoylhydrazin hergestellten neutralen bidentaten Hydrazonliganden wurden synthetisiert. Im Fall von Ru(III) wurden auch aus Benzaldehyd und verschiedenen Benzoylhydrazinen gewonnene monobasische bidentate Liganden eingesetzt. Die Komplexe wurden mittels spektroskopischer Methoden charakterisiert und mit Hilfe der cyclischen Voltammetrie untersucht. Es wird über die effiziente katalytische Oxidation von Alkoholen und 3,5-di- ^t Butyl-katechol in Gegenwart von N-Methyl-morpholin-N-oxid oderm-Chlorperbenzoesäure als Co-Oxidantien berichtet.

     

Synthesis and structural studies of new Mannich base ligands and their metal complexes

The new Mannich bases bis(1,4-diphenylthiosemicarbazide methyl) phosphinic acid H₃L¹ and bis(1,4-diphenylsemicarbazide methyl) phosphinic acid H₃L² were synthesised from the condensation of phosphinic acid, formaldehyde with 1,4-diphenyl thiosemicarbazide and 1,4-diphenylsemicarbazide, respectively. Monomeric complexes of these ligands, of general formulae K₂[Cr^III(L ⁿ )Cl₂], K₃[Mn^II(L ⁿ )Cl₂] and K[M(L ⁿ )] (M = Co(II), Ni(II), Cu(II), Zn(II) or Hg(II); n = 1, 2), are reported. The mode of bonding and overall geometry of the complexes were determined through physico-chemical and spectroscopic methods. These studies revealed octahedral geometries for the Cr(III), Mn(II) complexes, square planar for Co(II), Ni(II) and Cu(II) complexes and tetrahedral for the Zn(II) and Hg(II) complexes.     

Synthesis and antioxidant properties of some new thiazolyl coumarin derivatives

ABSTRACT

A three-component one-pot synthesis of new thiazolyl coumarin derivatives was carried out by condensing 3-acetyl-4-hydroxycoumarin, arylaldehydes, thiourea and ammonium acetate at reflux in DMC. The optimization details of the developed novel protocol are recorded. In addition, we have also synthesized these compounds via another second route in two steps. High atom-economy, excellent yields, simple procedure, and mild reaction conditions are the important features of this one-pot protocol. The chemical structures of the newly synthesized compounds were elucidated by using analytical (IR, ¹H NMR, ¹³C NMR). Further, all the compounds were screened for their antioxidant activities.     

Synthesis of some azo compounds and a study of their properties

11 azo compounds hitherto undescribed in the literature are synthesized. The azo components used were 8-hydroxyquinoline, resorcinol, pyrogallol, and 7-iodo-8-hydroxy-5-quinolinesulfonic acid, while the diazol components were sulfanilamide and a number of its derivatives. The acid dissociation constants for 8 azo compounds are determined by a solubility method and also spectrophotometrically. The constants are of the order 10^?7-10^?9.     

Synthesis of some azo compounds and a study of their properties

11 azo compounds hitherto undescribed in the literature are synthesized. The azo components used were 8-hydroxyquinoline, resorcinol, pyrogallol, and 7-iodo-8-hydroxy-5-quinolinesulfonic acid, while the diazol components were sulfanilamide and a number of its derivatives. The acid dissociation constants for 8 azo compounds are determined by a solubility method and also spectrophotometrically. The constants are of the order 10^–7-10^–9.     

Synthesis and fluorescent properties of some new unsymmetricbis-benzothiazolyl furans and thiophenes

Summary Some newmono- andbis-benzothiazolyl compounds with furan or thiophene nuclei were synthesized by multistep reactions from the corresponding furan and thiophene aldehydes. The data obtained from emission spectra show a large influence of the benzothiazole rings on the relative quantum efficiency of the compounds under investigation.

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Synthese und Fluoreszenzeigenschaften von neuen unsymmetrischenbis-Benzothiazolylfuranen und thiophenen

Zusammenfassung Einige neuebis-Benzothiazolylverbindungen mit einem Furan- bzw. Thiophenenring wurden in einer mehrstufigen Reaktion dargestellt. Die Fluoreszenzdaten der untersuchten Verbindungen zeigen einen großen Einfluß der Benzothiazolringe auf die relative Fluoreszenzquantenausbeute.

     

Synthesis and vibrational study of some polydentate ligands

Sodium salts of iminodiacetic acid (IDA), ethylenediaminetetraacetic acid (EDTA), 1,2-propylenediaminetetraacetic acid (PDTA) and 1,2-diaminocyclohexanetetraacetic acid (DCTA) were prepared by modification of the literature methods and their i.r. and Raman spectra were studied. The results obtained by application of both techniques allowed a better characterization of these polydentate ligands. Raman spectroscopy was specially useful in elucidating structural aspects in compounds containing acetate groups.     

Synthesis of picolinohydrazides and their evaluation as ligands in the zinc-catalyzed hydrosilylation of ketones

A set of picolinohydrazides was prepared by reaction between hydrazines and either 2-picolinic acid or ethyl pyridine-2-carboxylate, and characterized. These molecules were evaluated as ligands in the zinc-catalyzed hydrosilylation of ketones. Thus, several aromatic and aliphatic ketones were successfully reduced by diethoxymethylsilane as the hydride source in the presence of a catalytic system made of diethylzinc combined in situ to the picolinohydrazides described herein.     

Synthesis of new tridentate chiral aminoalcohols by a multicomponent reaction and their evaluation as ligands for catalytic asymmetric Strecker reaction

A one-step, multicomponent Mannich-type reaction between phenols, paraformaldehyde, and β-aminoalcohols in the presence of LiCl afforded N-2-hydroxybenzyloxazolidines with high ortho-selectivity. Hydrolytic or reductive ring opening of the oxazolidines provided a series of N-salicyl-β-aminoalcohols in 84-92% overall yield. The synthesized compounds were evaluated as ligands for a titanium-catalyzed catalytic asymmetric Strecker reaction. The reaction employing 10 mol % of catalyst provided the Strecker products in excellent yields and up to 98% ee.