Synthesis and Characterization of Some Triphenyltin(IV) Complexes from Sterically Crowded [((E)-1-{2-Hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]acetate Ligands and Crystal Structure Analysis of a Tetrameric Triphenyltin(IV) Compound

Four new triphenyltin(IV) complexes containing [((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]acetate ligands (L) have been synthesized with formulations of Ph₃SnLH. They have been studied by multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR, ¹¹⁹Sn M?ssbauer and IR spectroscopy. A full characterization of one complex, Ph₃SnL¹H (1), was accomplished by single crystal X-ray crystallography, which revealed the compound to be a macrocyclic tetramer. In the tetramer, the five coordinate tin atoms have distorted trigonal bipyramidal geometries with the three phenyl groups occupying equatorial positions, while an oxygen atom of the carboxylate group of one L ligand and the oxide O-atom (formerly the hydroxy group) of a second L ligand in an apical positions. The carboxylate ligands bridge adjacent tin atoms and coordinate in the zwitterionic form with the phenolic proton moved to the nearby nitrogen atom. ¹¹⁹Sn NMR results indicate that the tetrameric structures of the complexes in the solid state, in which the tin atoms are five-coordinated, dissociate in solution to yield four coordinate monomeric species.     

The synthesis,characterization and structures of some 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoic acid

The structures of several azo-benzoic acids, 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoic acid along with their precursors 2-hydroxy-5-[(E)-(aryldiazenyl)]benzaldehydes were confirmed using ¹H, ¹³C NMR, UV–VIS and IR spectroscopic techniques. UV–VIS absorption spectra were measured in pure organic solvents while complementary spectroscopic experiments using mixed solvent systems as well as in the presence of base were undertaken to characterize the different species present in solution. Both acid–base dissociation and azo–hydrazone tautomerism occurred in solution, with the extent of the individual equilibria being dependent on the solvent composition and/or pH of the medium. Molecular structures and geometries were optimized using the B3LYP density functional theory method employing the 6-31G(d) basis set.     

Synthesis, structure and magnetic properties of the first copper(II) complex with an (E)-4-aryl-4-oxo-2-butenoato ligand

A new binuclear Cu(II) complex with an (E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoato ligand (L) was successfully synthesized and characterized by elemental analysis and IR-spectroscopy. The structures of (E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoic acid (HL), and the corresponding (tetrakis)-μ-[(E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoato]-bis(ethanol)-copper(II) complex, [Cu₂L₄(C₂H₅OH)₂], were determined by single crystal X-ray analyses and are preliminarily discussed. This is the first complex of a transition metal with ligand L, as well as the first determined crystal structure of a metal complex with this type of ligand. Analysis of the magnetic susceptibility measurements of the isolated [Cu₂L₄(C₂H₅OH)₂] · H₂O complex shows the existence of a strong anti-ferromagnetic intradimer coupling, with an exchange integral value 2J of −260 cm⁻¹.     

Synthesis and characterization of the zinc(II) complex of a bleomycin analogue: a unique polymeric 2-[((2-(4-imidazoyl)ethyl)amino)carbony]-6-[((2-amino-2-methylpropyl)amino)methyl]pyridine zinc(II) nitrate complex

The reaction of 2-[((2-(4-imidazoyl)ethyl)amino)carbonyl]-6-[((2-amino-2-methylpropyl)amino)methyl]pyridine (L) with Zn^II(NO₃)₂·6H₂O has afforded a novel one-dimensional polymeric Zn^II complex, (Zn^II(L)(NO₃)₂)_n (2). Complex 2 crystallizes in the space group P2₁/n with a=8.955(3), b=13.216(3), c=18.941(3) Å, β=103.39(2)°, V=2180.6(10) ų, and Z=4. The geometry of each Zn^II is approximately a trigonal bipyramid: three nitrogens and one oxygen of the amide group are coordinated to the zinc while the fifth site is occupied by the imidazole nitrogen of a neighboring unit.     

Design, synthesis, and in vitro antifungal activity of 1-[(4-substituted-benzyl)methylamino]-2-(2,4-difluorophenyl)-3-(1H-1,2,4-triazol-1-yl)propan-2-ols

As part of our studies focused on the design of 1‐[((hetero)aryl‐ and piperidinylmethyl)amino]‐2‐phenyl‐3‐(1H‐1,2,4‐triazol‐1‐yl)propan‐2‐ols as antifungal agents, we report the development of new extended benzylamine derivatives substituted at the para position by sulfonamide or retrosulfonamide groups linked to alkyl or aryl chains. These molecules have broad‐spectrum antifungal activities not only against Candida spp., including fluconazole‐resistant strains, but also against a filamentous species (A. fumigatus). Concerning fluconazole resistance, selected compounds exhibit the capacity to overcome CDR and ERG11 gene upregulation and to maintain antifungal activity despite a recognized critical CYP51 substitution in C. albicans isolates. Synthesis, investigation of the mechanism of action by sterol analysis in a C. albicans strain, and structure–activity relationships (SARs) are reported.     

Coupling of cyclohexene oxide (CHO) and carbon disulfide (CS2) catalyzed by the asymmetric bis-Schiff-base Zn(II) complex

Based on the self-assembly of the asymmetric bis-Schiff-base ligand H₂L (H₂L = 4-((E)-(2-((E)-3,5-dibromo-2-hydroxybenzylideneamino)phenylimino)(phenyl)methyl-1-(4-chlorophenyl)-3-methyl-1H-pyrazol-5-ol) and Zn(OAc)₂·2H₂O, a new [Zn(L)] (1) was obtained and shown to efficiently catalyze the coupling of CHO (cyclohexene oxide) and CS₂ (carbon disulfide) in activation with [PPN]Cl (PPN⁺ = bis(triphenylphosphoranyidene)-ammonium), n-Bu₄NBr or n-Bu₄NI, where both poly[thio]carbonates and cyclic [thio]carbonates were produced, and the strong O/S exchange afforded the limited formation of trithiocarbonate in the cyclic [thio]carbonate byproducts.     

Synthesis of 2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine-1-oxide and its hydrazones

An efficient method for preparation of earlier unknown S-oxide of 2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine by oxidation of 2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine hydrochloride with hydrogen peroxide in H₂O or EtOH/H₂O followed by the reaction mixture neutralization with Na₂CO₃ has been described. Interaction of the S-oxide with acetaldehyde, butanal, benzaldehyde, 4-methoxybenzaldehyde and 4-pyridinecarboxaldehyde in EtOH, C₆H₆, in the mixture of acetonitrile and ethanol or ethanol and benzene affords the unknown hydrazones, N-organylmethylidene-2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine-1-oxides.     

Synthesis and Structures of Two Triorganotin(IV) Polymers R3Sn{O2CC6H4[N=C(H)}{C(CH3)CH(CH3)-3-OH]-p} n (R = Me and Ph) Containing a 4-[(2Z)-(3-Hydroxy-1-methyl-2-butenylidene)amino] benzoic Acid Framework

Two new polymeric triorganotin(IV) complexes R₃Sn{O₂CC₆H₄[N=C(H)}{C(CH₃)CH(CH₃)-3-OH]-p} _n ([Me₃Sn(LH)] _n : 1) and ([Ph₃Sn(LH)] _n : 2) containing a 4-[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)amino]benzoate (LH) framework were prepared. Both compounds have been characterized by ¹H, ¹³C, ¹¹⁹Sn NMR, IR and ¹¹⁹Sn Mössbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of complexes 1 and 2 reveal that they exist as polymeric zig-zag chains in which the LH-bridged Sn-atoms adopt a trans-R₃SnO₂ trigonal bipyramidal configuration with R groups in the equatorial positions and the axial sites occupied by an oxygen atom from the carboxylate ligand and the alcoholic oxygen atom of the next carboxylate ligand in the chain. The carboxylate ligands coordinate in the zwitterionic form with the alcoholic proton moved to the nearby nitrogen atom.     

Reaction of arylidenehydrazono-4-aryl-2,3-dihydrothiazole-5-carbonitriles with diethyl acetylenedicarboxylate. Synthesis of (Z)-ethyl 2-[((Z)-2-(E)-arylidenehydrazono)-4-oxo-thiazolidine-5-ylidene]acetates. NMR investigation

(Z)-Ethyl 2-[((Z)-2-(E)-arylidenehydrazono)-4-oxo-thiazolidine-5-ylidene]acetates were synthesized by three different methods: (a) reaction of arylidenehydrazono-4-aryl-2,3-dihydrothiazole-5-carbonitriles with diethyl acetylenedicarboxylate (DEAD) in acetic acid with prolonged reflux, (b) reaction between thiosemicarbazones, 2-arylidenemalononitriles and DEAD under conventional conditions or microwave irradiation, (c) one-pot three-component reaction of thiosemicarbazone derivatives, ylidene and DEAD. The thiazolinone adducts were obtained in good to excellent yields. NMR of the obtained products was investigated.     

Reaction of Aryl Iodides with (PCP)Pd(II)—Alkyl and Aryl Complexes: Mechanistic Aspects of Carbon—Carbon Bond Formation

The reaction of the PCP-type complex Pd(Me){2,6-(ⁱPr₂PCH₂)₂C₆H₃}( 3 ) with phenyl iodide results in the formation of Pd(I){2,6-(ⁱPr₂PCH₂)₂C₆H₃} ( 5 ), methyl iodide, toluene, and biphenyl. Formation of Pd(Ph){2,6-(ⁱPr₂PCH₂)₂C₆H₃}( 4 ) is observed during the reaction by ³¹P NMR. Reaction of 4 with aryl iodides results in the formation of 5 and Ph–Ph, Ph–Ar, and Ar–Ar, products indicative of a radical reaction. Under pseudo-first-order conditions, the rates of the reactions follow the order p-OMe > p-Me > H > p-NO₂ > m-Cl. The reaction is likely to involve electron transfer from 4 to the aryl iodide followed by fast decomposition of a postulated radical cation [Pd(Ph){2,6-(ⁱPr₂PCH₂)₂C₆H₃}]^+. ( 4 ^+.) to give a phenyl radical and [Pd{2,6-(ⁱPr₂PCH₂)₂C₆H₃}]⁺ ( 6 ⁺). Facile decomposition of the aryl iodide radical anion generates an aryl radical and I⁻. Recombination of aryl radicals gives rise to mixed biaryls, and 6 ⁺ combines with I⁻ to give 5 .     

Light-Switchable Antagonists for the Histamine H1 Receptor at the Isolated Guinea Pig Ileum

The histamine H₁ G protein-coupled receptor (GPCR) plays an important role in allergy and inflammation. Existing drugs that address the H₁ receptor differ in their chemical structure, pharmacology, and side effects. Light-controllable spatial and temporal activity regulation of photochromic H₁ ligands may contribute to a better mechanistic understanding and the development of improved correlations between ligand structure and pharmacologic effects. We report photochromic H₁ receptor ligands, which were investigated in an organ-pharmacological assay. Initially, five photochromic azobenzene derivatives of reported dual H₁–H₄ receptor antagonists were designed, synthesized, photochemically characterized, and organ-pharmacologically tested on the isolated guinea pig ileum. Among them, one compound [trans- 19 : (Z)-1-(4-chlorophenyl)-1-(4-methylpiperazin-1-yl)-N-(4-((E)-phenyldiazenyl)phenyl)methanimine] retained the antagonistic activity of its non-photochromic lead, and trans–cis isomerization by irradiation induced a fourfold difference in the pharmacological response. Further structural optimization resulted in two bathochromically shifted derivatives of 19 [NO₂-substituted 35 {(Z)-1-(4-chlorophenyl)-1-(4-methylpiperazin-1-yl)-N-(4-((E)-(4-nitrophenyl)diazenyl)phenyl)methanimine} and SO₃⁻-substituted 41 {4-((E)-(4-(((Z)-(4-chlorophenyl)(4-methylpiperazin-1-yl)methylene)amino)phenyl)diazenyl)benzenesulfonate}], which do not require the use of UV light for photoisomerization and which also have improved solubility and show reduced tissue impairment. The trans isomers of both compounds showed a remarkable increase in antagonistic activity relative to their lead trans- 19 ; furthermore, a 46-fold difference in activity on the isolated guinea pig ileum was observed between trans- and cis- 35 .     

Hydrothermal Synthesis and Characterization of Trimethyltin(IV) Derivatives with 2-Carboxyethylphosphonic and Benzylphosphonic acid: X-ray Crystal Structures of 2D Network Polymers

Two organotin(IV) derivatives, {[(CH₃)₃Sn]₆·[O₃P(CH₂)₂CO₂]₂·3H₂O} _n 1 and {[(CH₃)₂Sn]₄·[O₃PCH₂Ph]₄} _n 2, were synthesized by the reaction of trimethyltin(IV) chloride, 2-carboxyethylphosphonic acid and benzylphosphonic acid, respectively. Characterization of complexes 1 and 2 were achieved using elemental analysis, IR, TGA, NMR (¹H, ¹³C, ³¹P and ¹¹⁹Sn) spectroscopy and X-ray crystallography diffraction analysis. X-ray characterization show that complexes 1 and 2 are 2D network structures.     

Facile and general method for preparation of (E)-4-hydroxy-2-alkenals

A facile one-pot synthesis of (E)-4-hydroxy-2-alkenals such as (E)-4-hydroxy-2-nonenal, (E)-4-hydroxy-2-heptenal, and (E)-4-hydroxy-2-hexenal was achieved from the corresponding (2E,4E)-2,4-alkadienals by reduction-oxygenation with molecular oxygen and triethylsilane in the presence of cobalt(II) porphyrin as a catalyst followed by treatment with trimethylphosphite.     

Zur Heck-Reaktion von 1-Chloralk-1-inen – Synthese und Charakterisierung von 1,3-disubstituierten 7-(Prop-2-inyliden)bicyclo[2.2.1]heptanen und anderen Bicyclen

The Heck reaction of cyclohexene with 1-chloroalk-1-ynes ClC≡CR 1 (R = Ph a , c-Hex b , n-Bu c , n-Oct d ) using [Pd(OAc)₂]/NaO₂CH/[NEt₃Bz]Cl as catalyst system (DMF, 25 °C) affords 1,3-disubstituted 7-(prop-2-ynylidene)bicyclo[2.2.1]heptanes 2 as tandem products by reaction of cyclohexene and ClC≡CR in a ratio of 1:2. To a smaller extent, substituted 7-[(cyclohexenyl)methylidene]bicyclo-[2.2.1]heptanes 3 (tandem products by reaction of cyclohexene and ClC≡CR in a ratio of 2:1) and the regular Heck products (alkynylcyclohexenes 4 ) are formed. The homocoupling of 1 to give RC≡C–C≡CR does not take place, except for R = n-Oct where it proceeds as side reaction. The analogous reaction of ClC≡CR with cycloheptene affords the 2:1 products (substitued 8-[(cycloheptenyl)methylidene]biyclo[3.2.1]octanes 6 ) as main products and the 1:2 products (1,3-disubstituted 7-(prop-2-ynylidene)bicyclo[3.2.1]-octanes 5 ) as well as the regular Heck products (alkynylcycloheptenes 7 ) as side products. The ratio 5 : 6 is strongly influenced by the ratio cycloheptene : 1 . The products 2 , 5a and 6 were isolated and characterized by means of ¹H and ¹³C NMR spectroscopy. The molecular structures of 7-(1,3-diphenylprop-2-ynylidene)bicyclo[2.2.1]heptane ( 2a ) and 8-[(cyclo-heptenyl)phenylmethylidene)]bicyclo[3.2.1]octane ( 6a ) (as mixture of the cyclohept-3- and -4-enyl double bond isomers) were determined by single-crystal X-ray structure analysis.     

Bis[4-(methylthio)phenylmethyleneaminophenyl] disulfide, 2-[4-(methylthio)phenyl]-2,3-dihydro-1,3-benzothiazole,and its nickel(II) and cobalt(II) complexes: Synthesis,adsorption on gold surface and electrochemical characterization

2-[4-(Methylthio)phenyl]-2,3-dihydro-1,3-benzothiazole (1) and bis[4-(methylthio)phenylmethylene-aminophenyl] disulfide (2) were synthesized. Novel coordination compounds of Ni(II) and Co(II) with 2-[4-(methylthio)phenylmethyleneamino]thiophenol, M(1)₂ (M=Co (3); M=Ni (4)), were prepared by reacting 1 with M(OAc)₂·6H₂O or MCl₂·6H₂O in EtOH solution. The structure of 2 was proved by X-ray crystallography. Electrochemical behavior of 1–4 in CH₃CN solution and at the surface of a gold electrode was studied by cyclic voltammetry. The modification of the electrode by ligand 1 and its complexes with Ni²⁺ and Co²⁺ is described in detail. Two procedures were used to obtain a self-assembled monolayer of a metal complex on the gold surface: the adsorption of prepared coordination compound 3 or 4 on the electrode and the initial modification of the electrode with ligand 1 followed by the formation of a coordination complex between the ligand adsorbed on the electrode and a metal salt occurring in solution. On the basis of the electrochemical data, it was found that the structure of complexes formed on the surface differs from that of the complexes produced in solution.     

Unusual dirhenium complexes containing the bis[2-(diphenylphosphino)phenyl]ether ligand including a terephthalate-bridged tetrarhenium compound

The synthesis, structures and reactivity of unsymmetrical multiply-bonded dirhenium(IV,II) and dirhenium(III,II) complexes that contain the bis[2-(diphenylphosphino)phenyl]ether ligand (L¹) are described, including the isolation and structural characterization of the novel terephthalate-bridged tetrarhenium complex [Re₂Cl₄(η³-L¹)]₂(μ-O₂CC₆H₄CO₂) in which there is weak electronic coupling between the pairs of dirhenium centers.     

Fluoro Substituted Monomeric and Uni-Dimensional Polymeric Organotin(IV) Esters of (E)-4-oxo-4-((3-trifluoromethyl)phenyl)amino)but-2-enoic acid; Synthesis, Characterization and Their In vitro Inhibitory Studies

Inhibition effects of novel organotin(IV) esters of (E)-4-oxo-4-((3-trifluoromethyl)phenyl)amino)but-2-enoic acid have been studied against bacterial, fungal, tumoral and insecticidal strains. The complexes have shown potency against all these strains and is attributed to the multiple interactive sites of the ligand that not only change the environment around tin but also can make interactions with DNA. The synthesized complexes were characterized by physical, spectral, analytical and multinuclear nmr (¹H, ¹³C, ¹¹⁹Sn) data. The X-ray structure analysis of the complex is reported.     

Linoleic acid metabolism in the red algaLithothamnion corallioides: Biosynthesis of 11(R)-hydroxy-9(Z),12(Z)-octadecadienoic acid

Incubation of [1-¹⁴C]linoleic acid with an enzyme preparation obtained from the red algaLithothamnion corallioides Crouan resulted in the formation of 11-hydroxy-9(Z),12(Z)-octadecadienoic acid as well as smaller amounts of 9-hydroxy-10(E),12(Z)-octadecadienoic acid, 13-hydroxy-9(Z),11(E)-octadecadienoic acid and 11-keto-9(Z),12(Z)-octadecadienoic acid. Steric analysis showed that the 11-hydroxyoctadecadienoic acid had the (R) configuration. The 9- and 13-hydroxyoctadecadienoic acids were not optically pure, but were due to mixtures of 75% (R) and 25% (S) enantiomers (9-hydroxyoctadecadienoate), and 24% (R) and 76% (S) enantiomers (13-hydroxy-octadecadienoate). 11-Hydroxyoctadecadienoic acid was unstable at acidic pH. In acidified water, equal parts of 9(R,S)-hydroxy-10(E),12(Z)-octadecadienoate and 13(R,S)-hydroxy-9(Z),11(E)-octadecadienoate, plus smaller amounts of the corresponding (E),(E) isomers were produced. In aprotic solvents, acid treatment resulted in dehydration and in the formation of equal amounts of 8,10,12- and 9,11,13-octadecatrienoates. The enzymatic conversion of linoleic acid into the hydroxyoctadecadienoic acids and the ketooctadecadienoic acid was oxygen-dependent; however, inhibitor experiments indicated that neither lipoxygenase nor cytochrome P-450 were involved in the conversion. This conclusion was supported by experiments with¹⁸O₂ and H₂ ¹⁸O, which demonstrated that the hydroxyl oxygen of the hydroxy-octadecadienoic acids and the keto oxygen of the 11-ketooctadecadienoic acid were derived from water and not from molecular oxygen. The term “oxylipin” was introduced recently (ref. 1) as an encompassing term for oxygenated compounds which are formed from fatty acids by reaction(s) involving at least one step of mono- or dixoygenase-catalyzed oxygenation.     

Solvothermal Synthesis and Crystal Structure of a Novel 3D Triorganotin Polymer Containing Polyfunctional Ligand 5-mercapto-1(H)-tetrazoleacetic acid

A novel 3D tri-n-butyltin complex [(n-Bu₃Sn)₂(C₂H₂N₄SCO₂)]_n (1) has been solvothermally synthesized and structurally characterized by elemental analysis, FT-IR, NMR (¹H, ¹³C, and ¹¹⁹Sn) spectra and X-ray crystallography. X-ray data of complex 1 reveals that it is a 3D tri-n-butyltin coordination polymer with a metal-organic framework (MOF) structure , significant N → Sn interactions plays an important role in the construction of this structure.     

Metabolic profile of linoleic acid in stored apples: Formation of 13(R)-hydroxy-9(Z),11(E)-octadecadienoic acid

During our ongoing project on the biosynthesis of R-(+)-octane-1,3-diol the metabolism of linoleic acid was investigated in stored apples after injection of [1-¹⁴C]-, [9,10,12,13-³H]-, ¹³C₁₈- and unlabeled substrates. After different incubation periods the products were analyzed by gas chromatography-mass spectroscopy (MS), high-performance liquid chromatography-MS/MS, and HPLC-radiodetection. Water-soluble compounds and CO₂ were the major products whereas 13(R)-hydroxy- and 13-keto-9(Z),11(E)-octadecadienoic acid, 9(S)-hydroxy-and 9-keto-10(E),12(Z)-octadecadienoic acid, and the stereoisomers of the 9,10,13- and 9,12,13-trihydroxyoctadecenoic acids were identified as the major metabolites found in the diethyl ether extracts. Hydroperoxides were not detected. The ratio of 9/13-hydroxy- and 9/13-keto-octadecadienoic acid was 1∶4 and 1∶10, respectively. Chiral phase HPLC of the methyl ester derivatives showed enantiomeric excesses of 75% (R) and 65% (S) for 13-hydroxy-9(Z),11(E)-octadecadienoic acid and 9-hydroxy-10(E),12(Z)-octadecadienoic acid, respectively. Enzymatically active homogenates from apples were able to convert unlabeled linoleic acid into the metabolites. Radiotracer experiments showed that the transformation products of linoleic acid were converted into (R)-octane-1,3-diol. 13(R)-Hydroxy-9(Z), 11(E)-octadecadienoic acid is probably formed in stored apples from 13-hydroperoxy-9(Z),11(E)-octadecadienoic acid. It is possible that the S-enantiomer of the hydroperoxide is primarily degraded by enzymatic side reactions, resulting in an enrichment of the R-enantiomer and thus leading to the formation of 13(R)-hydroxy-9(Z),11(E)-octadecadienoic acid.