Polarographic behaviour of 1,3-bis[(2-pyridyl)methyleneamino]thiourea (PMAT) in absence and presence of Triton X-100

The polarographic behaviour of 1,3-bis[(2-pyridyl)methyleneamino]thiourea (PMAT) in solutions of varyingpH has been studied both in the absence and presence of Triton X-100 (T.X-100). The mechanism for the reduction process is discussed. The adsorption effect of electrochemically inactive T.X-100 on the polarographic waves ofPMAT has been investigated. The values of the kinetic parameters for the electrode reaction at differentpH values have been computed. The applicability of the polarographic method for determination ofPMAT is also discussed.

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Das polarographische Verhalten von 1,3-Bis[(2-pyridyl)methylenamino]-thioharnstoff (PMAT) in Anwesenheit und Abwesenheit von Triton X-100. Die polarographische Bestimmung vonPMAT

Zusammenfassung Es wurde das polarographische Verhalten vonPMAT in Lösungen mit verschiedenempH sowohl in Gegenwart als auch ohne Triton X-100 (T.X-100) untersucht. Es wird ein Mechanismus für den Reduktionsprozeß diskutiert. Der Adsorptionseffekt des elektrochemisch inaktiven T.X-100 wurde hinsichtlich der polarographischen Wellen vonPMAT untersucht. Die kinetischen Parameter der Elektrodenreaktion wurden für verschiedenepH-Werte ermittelt. Ebenso wird die Anwendbarkeit der polarographischen Methode für die Bestimmung vonPMAT diskutiert.

     

Preparation of palladium complexes of 1,3-di(2-pyridyl)propane derivatives and their use in norbornene polymerization

A variety of neutral palladium(II) complexes [Pd(L–L)Cl₂] containing 1,3-di(2-pyridyl)propane (1), 1,3-bis(2-pyridyl)-2-pentylpropane (2), 1,3-bis(2-pyridyl)-2-phenylpropane (3a), 1,3-bis(2-pyridyl)-2-tolylpropane (4), and 1,3-bis(2-pyridyl)-2-ferrocenylpropane (5) as chelate ligands (L–L) have been synthesized. The crystal structures of 1,3-diphenyl-2,4-di-pyridin-2-yl-butan-1-ol (3b), 5, [(2)PdCl₂], [(4)PdCl₂], and [(5)PdCl₂] have been determined and show a square planar geometry at palladium(II). The neutral complexes were tested in the polymerization of norbornene and copolymerization of norbornene with norbornene derivatives. The complex bearing the pentyl group exhibited high reactivity to give up to 5.9×10⁵ in molecular weight for the homopolymerization. When [(4)PdCl₂] or [(5)PdCl₂] was used as a catalyst, homopolymers insoluble at 150 °C in trichlorobenzene were obtained. However, copolymerization of norbornene with norbornene derivatives 8a–d catalyzed by [(4)PdCl₂] gave soluble copolymers with molecular weights up to 5.1×10⁵.     

Spectroscopic, thermal and structural studies of cocrystal of 2,2′-diamino-4,4′-bis(1,3-thiazole) with 4,4′-bipyridine, 1,2-bis(4-pyridyl)ethylene and 1,3-bis(4-pyridyl)propane

Three new cocrystals based upon 2,2′-diamino-4,4′-bis(1,3-thiazole) (DABTZ) with 4,4′-bipyridine (4,4′-bipy), 1,2-bis(4-pyridyl)ethylene (bpe) and 1,3-bis(4-pyridyl)propane (bpp): [(DABTZ) (4,4′-bipy)], [(DABTZ) (bpe)] and [(DABTZ) (bpp)] have been synthesized and characterized by elemental analysis, IR-, ¹H NMR-, ¹³C NMR spectroscopy and studied by thermal and X-ray crystallography. Self-assembly of these compounds in the solid state is likely caused by both hydrogen bonding, and π-π stacking.     

Synthesis,characterization, anti-fungi and anti-bacterial activity of new [(2-pyridyl)-3-isatin]-bishydrazone

New [(pyridine-2-carboxaldhyde)-3-isatin]-bishydrazone (cpish), [(2-acetylpyridine)-3-isatin]-bishydrazone (apish), and [(2-benzoyl pyridine)-3-isatin]-bishydrazone (bpish) have been synthesized and characterized by the elemental analysis, IR, NMR and electronic spectra. The bioefficiency of the [(2-pyridyl)-3-isatin]-bishydrazones have been examined for their in-vitro antibacterial and antifungal activity against many types of bacteria and fungal cultures which are common contaminants of the environment in Egypt and some of which are involved in human and animal diseases or in plant diseases or frequently reported from contaminated soil, water, and food substances. The results of these studies indicate that the [(2-pyridyl)-3-isatin]-bishydrazones possess notable antimicrobial properties.     

The spectrophotometric determination of copper with disodium 3-hydroxy-4-[(6-methyl-2-pyridyl)azo]-2,7-naphthalenedisulfonate N-oxide

Summary The synthesis and characterization of disodium 3-hydroxy-4-[(6-methyl-2-pyridyl)azo]-2, 7-naphthalenedisulfonateN-oxide and its application to the spectrophotometric determination of trace amounts of copper are described. The effects due to pH, time, reagent concentration and diverse ions are reported. The reagent exhibits good specificity for copper. Beer's law is obeyed and the molar absorbance coefficient at 536 nm is 1.8×10⁴.

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Die spektrophotometrische Bestimmung von Kupfer mit Dinatrium-3-hydroxy-4-[(6-methyl-2-pyridyl)azo]-2, 7-napbthalindisulfonat-N-oxid

Zusammenfassung Die Synthese und die Eigenschaften von Dinatrium-3-hydroxy-4-[(6-methyl-2-pyridyl)azo]-2, 7-naphthalindisulfonat-N-oxid sowie dessen Anwendung zur spektrophotometrischen Bestimmung von Kupferspuren wurden beschrieben. Die Einflüsse von pH, Zeit, Reagenskonzentration und von verschiedenen Ionen wurden angegeben. Das Reagens zeigt gute Spezifität gegenüber Kupfer. Das Beersche Gesetz wird befolgt. Der molare Extinktionskoeffizient bei 536 nm beträgt 1,8·10⁴.

     

Synthesis of 2'-O-[2-[(N,N-dimethylamino)oxy]ethyl] modified nucleosides and oligonucleotides.

A versatile synthetic route has been developed for the synthesis of 2'-O-[2-[(N,N-dimethylamino)oxy]ethyl] (abbreviated as 2'-O-DMAOE) modified purine and pyrimidine nucleosides and their corresponding nucleoside phosphoramidites and solid supports. To synthesize 2'-O-DMAOE purine nucleosides, the key intermediate B (Scheme 1) was obtained from the 2'-O-allyl purine nucleosides (13a and 15) via oxidative cleavage of the carbon-carbon bond to the corresponding aldehydes followed by reduction. To synthesize pyrimidine nucleosides, opening the 2,2'-anhydro-5-methyluridine 5 with the borate ester of ethylene glycol gave the key intermediate B. The 2'-O-(2-hydroxyethyl) nucleosides were converted, in excellent yield, by a regioselective Mitsunobu reaction, to the corresponding 2'-O-[2-[(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)oxy]ethyl] nucleosides (18, 19, and 20). These compounds were subsequently deprotected and converted into the 2'-O-[2-[(methyleneamino)oxy]ethyl] derivatives (22, 23, and 24). Reduction and a second reductive amination with formaldehyde yielded the corresponding 2'-O-[2-[(N,N-dimethylamino)oxy]ethyl] nucleosides (25, 26, and 27). These nucleosides were converted to their 3'-O-phosphoramidites and controlled-pore glass solid supports in excellent overall yield. Using these monomers, modified oligonucleotides containing pyrimidine and purine bases were synthesized with phosphodiester, phosphorothioate, and both linkages (phosphorothioate and phosphodiester) present in the same oligonucleotide as a chimera in high yields. The oligonucleotides were characterized by HPLC, capillary gel electrophoresis, and ESMS. The effect of this modification on the affinity of the oligonucleotides for complementary RNA and on nuclease stability was evaluated. The 2'-O-DMAOE modification enhanced the binding affinity of the oligonucleotides for the complementary RNA (and not for DNA). The modified oligonucleotides that possessed the phosphodiester backbone demonstrated excellent resistance to nuclease with t(1/2) > 24 h.     

Nitrogen-NMR Studies on the Protonation of 2-(Aminomethyl)pyridine and Tris[(2-pyridyl)methyl]amine

¹⁴N- and ¹⁵N-NMR spectra have been recorded for 2-(aminomethyl)pyridine ( 1 ), tris[(2-pyridyl)methyl]amine ( 2 ), and some of their protonated forms. For 1 , the most basic site is the aliphatic N-atom, whereas for 2 the pyridine N-atoms are more basic, in contrast to what might be expected for a tertiary aliphatic amine.     

Synthesis of 2-Aryl and 2-Hetaryl Derivatives of 2'-Aminospiro[(1,3-dioxane)-5,5'-thiazolin]-4'-one and Spiro[(1,3-dioxane)-5,5'-thiazolidine]2',4'-dione

2-(Het)aryl derivatives of 2'-aminospiro[(1,3-dioxane)-5,5'-thiazolin]-4'-one or spiro[(1,3-dioxane)-5,5'-thiazolidine]-2',4'-dione are formed by the acid catalyzed interaction of 2-amino-5,5-bis(hydroxymethyl)-4-thiazolinone or its oxo analog 5,5-bis(hydroxymethyl)thiazolidine-2,4-dione with (hetero)aromatic aldehydes.     

Reaction of N-(4-Pyridylrnethyl)benzamide N-oxides and N-[(α-acetoxy)-4-pyridylmethyl]benzamides with 1,3-diphenyl-1,3-propanedione

Reaction of N-(4-pyridylmethyl)benzamide N-oxides 2 with 1,3-diphenyl-1,3-propanedione in the presence of acetic anhydride afforded 1,1-dibenzoyl-2-(4-pyridyl)-2-(benzoylamino)ethanes 4 in low yield. Treatment of N-[(α-acetoxy)4-pyridylmethyl]benzamides 3 with 1,3-diphenyl-1,3-propanedione in the presence of triethylamine and chloroform as a solvent provided 4 in high yield. Reaction of 4 with nucleophiles as hydrazine, methyl and phenylhydrazine gave the corresponding pyrazoles 5 .     

Spectrophotometric Evaluation of Acidity Constants of Diprotic Acids: Errors Involved as a Consequence of an Erroneous Choice of the Limit Absorbances

Abstract

The erroneous choice of the limit absorbances of a diprotic acid leads to the inaccurate acidity constants to be evaluated. The errors thus implied are calculated for two hypothetical systems. In addition, two practical systems, isonicotinic acid and 1,3-bis [(2-pyridyl)methyleneamino]guanidine have also been the subject of study having had their acidity constants evaluated accurately.     

Multicomponent Synthesis of 1,3-Bis[(alkylsulfanyl)methyl]-1,3,5-triazinan-2-ones

Russian Journal of Organic Chemistry - Previously unknown 5-alkyl-1,3-bis[(alkylsulfanyl)methyl]-1,3,5-triazinan-2-ones have been syn­thesized by three-component condensation of available...     

Octa-membered Water Ring Chain Based on Sulfonic Group in Ni(II) Complex with 2-[(E)-(2-Oxidophenyl)methyleneamino] Ethanesulfonato and 2,2′-Bipyridinyl

The title compound, [Ni(tssb)(2,2-bipy)2]·5(H2O) 1 (tssbH2 =2-[(E)-(2-oxido- phenyl)methyleneamino]ethanesulfonato, 2,2-bipy = 2,2′-bipyridinyl), belongs to orthorhombic, space group Pbcn with a = 20.3983(18), b = 17.6929(15), c = 17.0897(15) nm, V = 6167.8(9) nm3, Mr = 688.38, Z = 8, Dc = 1.481 g·cm-3, F(000) = 2880, μ = 0.758 mm-1 and S =1.099. Each NiII atom is six-coordinated by one N and one O atoms from one tssb2-anion and four N atoms from two 2,2-bipy ligands to give a distorted octahedral geometry. Noticeably, there exists a rare octa-membered water ring which presents a 1D chain by sulfonic group.     

Variable temperature H and Si NMR of diastereomeric 1,3-dihydroxy-1,3-bis[(2-dimethylaminomethyl)phenyl]-1,3-divinyldisiloxanes

Variable temperature NMR experiments of diastereomeric 1,3-dihydroxy-1,3-bis[(2-dimethylaminomethyl)phenyl]-1,3-divinyldisiloxanes, meso-1 and rac-1 having intramolecular hydrogen bondings were carried out. As temperature increased, the ¹H NMRs of hydroxy groups of 1 resulted in a low frequency and their ²⁹Si NMRs were very slightly shifted to a low frequency. Interestingly, the ¹H NMR of two benzylic protons was split more widely as temperature increased.     

Synthesis and analytical properties of di(2-pyridyl)-N,N-di[(8-quinolyl)amino]methane

The synthesis and preliminary analytical assessment of di(2-pyridyl)-N,N-di[(8-quinolyl)-amino]methane is reported. It shows some potential as a reagent for iron(II).     

Synthesis of 1,3-bis[(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dienylidene)(dimethoxyphosphoryl)methyl]-4,6-dimethoxybenzene

A reaction of 1,3-dimethoxybenzene with dimethyl (3,5-di-tert-butyl-4-oxocyclohexa-2,5-dienylidenemethyl)phosphonate gave rise to 1,3-bis[(3,5-di-tert-butyl-4-hydroxyphenyl)-(dimethoxyphosphoryl)methyl]-4,6-dimethoxybenzene, which was oxidized to 1,3-bis[(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dienylidene)(dimethoxyphosphoryl)methyl]-4,6-dimethoxy-benzene.     

Pseudorotaxane-type n-hydrocarbon container. Metallacyclodimer of ionic palladium(II) complexes containing 1,3-bis(4-pyridyl)tetramethyldisiloxane

An unusual "pseudorotaxaned n-alkane within a metalla-cyclodimer" system, C(n)H(2n+2)@[(Me(4)en)Pd(L)](2)(CF(3)SO(3))(4) (n = 5, 6, 7; Me(4)en = N,N,N',N'-tetramethylethylenediamine; L = 1,3-bis(4-pyridyl)tetramethyldisiloxane), was constructed. This system is the first pseudorotaxane-type petroleum container achieved via the appropriate size effect.     

Molecular structures of methyl 4-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]-1-methyl-1H-pyrazol-5-carboxylate and methyl 4-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]-1-methyl-1H-pyrazol-3-carboxylate

The structure of methyl 4-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]-1-methyl-1H-pyrazol-5-carboxylate is determined by X-ray crystallography and further used to elucidate the structure of methyl 4-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]-1-methyl-1H-pyrazol-3-carboxylate, using the data of homo- and heteronuclear 2D NMR correlation spectroscopy.     

Spectroscopic study of the reaction of cis-1,3-di(2-pyridyl)[60]fullereno[1,2-c]pyrrolidine and 2-(2-pyridylmethyl)-1,3-di(2-pyridyl)[60]fullereno[1,2-c]pyrrolidine with zinc meso-tetraphenylporphyrinate

Axial coordination of the pyrrolidine nitrogen atom in cis-1,3-di(2-pyridyl)[60]fullereno[1,2-c]pyrrolidine to zinc meso-tetraphenylporphyrinate in cyclohexane gives rise to a donor-acceptor complex. The formation constant of the 1: 1 porphyrin—fullerenopyrrolidine complex was determined by spectrophotometric and fluorescence titration. The values of the constant estimated by spectrophotometric and fluorescence methods are 1.2·10⁴ and 9.7·10³ L mol⁻¹, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2265–2269, October, 2005.     

Octa-membered Water Ring Chain Based on Sulfonic Group in Ni(Ⅱ) Complex with 2-[(E)-(2-Oxidophenyl)methyleneamino]Ethanesulfonato and 2,2''-Bipyridinyl

The title compound, [Ni(tssb)(2,2-bipy)2]·5(H2O) 1 (tssbH2 =2-[(E)-(2-oxido-phenyl)methyleneamino]ethanesulfonato, 2,2-bipy = 2,2'-bipyridinyl), belongs to orthorhombic,space group Pbcn with a = 20.3983(18), b = 17.6929(15), c = 17.0897(15) nm, V = 6167.8(9) nm3,Mr= 688.38, Z = 8, Dc = 1.481 g·cm-3, F(000) = 2880, μ = 0.758 mm-1 and S =1.099. Each NiⅡ atom is six-coordinated by one N and one O atoms from one tssb2- anion and four N atoms from two 2,2-bipy ligands to give a distorted octahedral geometry. Noticeably, there exists a rare octa-membered water ring which presents a 1D chain by sulfonic group.     

Syntheses,crystal structures and properties of copper(II) complexes of 1,3-bis[(4-methyl-5-imidazol-1-yl)ethylideneamino]propan-2-ol and 1,3-bis[(4-methyl-5-imidazol-1-yl)ethylideneamino] propane

The syntheses of two polydentate ligands comprising imidazole donors, 1,3-bis[(4-methyl-5-imidazol-1-yl) ethylideneamino]propan-2-ol (BIPO), 1,3-bis[(4-methyl-5-imidazol-1-yl)ethylideneamino]propane (BIP), and their copper(II) complexes [Cu(BIPO)(ClO₄)(H₂O)] (NO₃) · H₂O (1) and [Cu(BIP)(ClO₄)](ClO₄) · 2H₂O (2) are reported. Single-crystal structural analyses show that (1) adopts an elongated octahedral geometry with the axial positions occupied by a perchlorate oxygen atom and an aqua ligand, while (2) adopts a distorted square-pyramidal geometry with the axial positions occupied by a perchlorate oxygen atom. Electronic spectra in aqueous solution indicate that both (1) and (2) adopt square-pyramidal geometry. Cyclic voltammetry in aqueous solution gives reduction waves at –0.07 and –0.08 V versus s.c.e. for (1) and (2), respectively. The low reduction potential and general reversibility of the redox reaction of (1) and (2) indicate that BIPO and BIP are flexible enough to stabilize both Cu^II and Cu^I forms of the complexes.