DI-μ-CHLORO-BIS[l,2-BIS(DIPHENYLPHOSPHINO)-ETHANEPALLADIUM(II)]: SYNTHESIS AND CRYSTAL STRUCTURE

Abstract

On reacting 1,2-bis(diphenylphosphino)ethanedichloropalladium(II) with equimolar amount of silver perchlorate, a binuclear complex, di-μ-chloro-bis[1,2-bis(diphenylphosphino)ethane-palladium(II)] (1) is formed. The crystal structure of 1 has been solved. It crystallizes with two chloroform molecules. Chloro bridges are symmetrical and normal (Pd-Cl～2.414(3) Å). The immediate environment around palladium is slightly distorted square planar and the P-Pd-P angle is ～85°. IR bands at 290 and 270cm^?1 are observed for the chloro-bridged core of the complex.     

OXIDATION OF ALKYLCYANOHYDRAZINES TO AZO-BIS NITRILES USING OXONE®–POTASSIUM BROMIDE IN AQUEOUS MEDIUM

ABSTRACT

Azo-bis nitriles were prepared in good yields and high purity by oxidation of corresponding 1,2-bis-dialkylcyano hydrazines using oxone-potassium bromide in aqueous medium.     

Synthesis of New Spirodifuranose Derivatives by Reduction of Stable Spiro-Endoperoxides

Synthesis of three new stable spirodifuranose derivatives (3, 5, and 7), which cannot be obtained easily using ordinary synthetic methods, has been achieved by reduction of 3-O-acetyl and 3-O-methyl derivatives of (4R)-1,2-O-alkylidene-5-eno-4,7-epidioxy-5,6,8-trideoxy-α-D-threo-1,4-furano-4,7-diulo-octoses (1, 4, and 6).     

Synthesis and spectral characterization of a new symmetric bidentate Schiff-base and its zinc complexes

A new symmetric bidentate Schiff base N,N′-bis [(E)-3-(2-nitrophenyl)allylidene)]benzene-1,2-diamine (L) and its complexes with general formula ZnLX₂ (X = chloride, bromide, iodide, thiocyanate and azide) are described. The authenticity of the ligand and complexes have been established by microanalysis, electronic, MS, FT-IR, ¹H and ¹³C NMR spectra, and by molar conductivity measurements. All compounds are non-electrolytes in DMF. The analytical data confirmed that the metal to ligand ratio in the complexes is 1 : 1. The complexes have pseudotetrahedral geometry with C_2V point group.     

Asymmetric catalysis,part 91: Enantioselective monophenylation ofcis-1,2-cyclopentanediol with triphenylbismuth diacetate and chiral copper(II) complexes as catalysts

Summary The monophenylation ofcis-1,2-cyclopentanediol with triphenylbismuth diacetate in the presence of chiral Cu(II) complexes as catalysts gavecis-2-hydroxy-1-phenoxy-cyclopentane with enantiomeric excesses up to 38%. The optically active ligands used were triamine derivatives of 2,6-bis(aminomethyl)pyridine and diamine derivatives of 2-(aminomethyl)pyridine. Selectivity in the monophenylation occurred only in the presence of the latter as auxiliary ligands.

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Asymmetrische Katalysen, 91. Mitt.: Enantioselektive Monophenylierung voncis-1,2-Cyclopentandiol mit Triphenylwismutdiacetat und chiralen Kupfer(II)-Komplexen als Katalysatoren

Zusammenfassung Die Monophenylierung voncis-1,2-Cyclopentandiol mit Triphenylwismutdiacetat in Gegenwart chiraler Cu(II)-Komplexe als Katalysatoren ergabcis-2-Hydroxy-1-phenoxy-cyclopentan mit Enantiomerenüberschüssen von bis zu 38%. Die eingesetzten optisch aktiven Liganden waren Triamin-Derivate von 2,6-bis(Aminomethyl)pyridin und Diamin-Derivate von 2-(Aminomethyl)pyridin. Selektivität bei der Monophenylierung war nur in Gegenwart letzterer als Auxiliar-Liganden zu beobachten.

     

Coordination of di- and triimine ligands at ruthenium(II) and ruthenium(III) centers: structural,electrochemical and radical scavenging studies

Herein, we explore the coordination of di- and triimine chelators at ruthenium(II) and ruthenium(III) centers. The reactions of 2,6-bis-((4-tetrahydropyranimino)methyl)pyridine (thppy), N¹,N²-bis((3-chromone)methylene)benzene-1,2-diamine (chb), and tris-((1H-pyrrol-2-ylmethylene)ethane)amine (H₃pym) with trans-[Ru^IICl₂(PPh₃)₃] afforded the diamagnetic ruthenium(II) complex cis-[RuCl₂(thppy)(PPh₃)] (1) and the paramagnetic complexes [mer-Ru₂(μ-chb)Cl₆(PPh₃)₂] (2), and [Ru(pym)] (3), respectively. The complexes were characterized by IR, NMR, and UV–vis spectroscopy and molar conductivity measurements. The structures were confirmed by single crystal X-ray diffraction studies. The redox properties of the metal complexes were probed via cyclic- and squarewave voltammetry. Finally, the radical scavenging capabilities of the metal complexes towards the NO and 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) radicals were investigated     

Synthesis and in vitro cytotoxicity of novel dinuclear platinum(II) complexes containing a chiral tetradentate ligand

A series of novel dinuclear platinum(II) complexes with a chiral tetradentate ligand, (1R,1′R,2R,2′R)-N¹,N¹′-(1,2-phenylenebis(methylene))dicyclohexane-1,2-diamine (HL), and mono-carboxylic acid derivatives as ligands have been designed, synthesized, and characterized. In vitro cytotoxicity evaluation of synthesized complexes against human HepG-2, A549, HCT-116, and MCF-7 cancer cell lines has been conducted by MTT assays. All compounds showed antitumor activity to HepG-2 and HCT-116 cell lines. Compound L2 exhibited better cytotoxicity than that of carboplatin against HepG-2 and A549 cell lines and also showed comparable activity against HCT-116 cell line.     

Synthesis and in vitro cytotoxicity of platinum(II) complexes with chiral N-monosubstituted 1,2-cyclohexyldiamine derivatives as the carrier groups

Eight platinum(II) complexes with the new chiral ligands, (1R,2R)-N ¹-(pyridine-2-ylmethyl) cyclohexane-1,2-diamine (R) or (1S,2S)-N ¹-(pyridine-2-ylmethyl) cyclohexane-1,2-diamine (S) as the carrier groups were designed, synthesized, and spectrally characterized. All platinum(II) complexes showed much better aqueous solubility than cisplatin and oxaliplatin. In vitro cytotoxicity of the compounds against human HepG-2, MCF-7, A549, and HCT-116 cell lines was evaluated. Results indicate that all compounds with R as the carrier group showed cytotoxicity against HCT-116, A549, and MCF-7 cell lines; however, all compounds with S as carrier group exhibited disappointing cytotoxicity against tested cell lines. Compound R2, bearing ClCH₂COO^- as leaving group, exhibited better cytotoxicity than that of carboplatin against A549 and MCF-7 cell lines and also showed close activity to oxaliplatin against HCT-116 cell line.     

Preparation of l-Threoninol and Its Bisoxazoline Derivative

Abstract

(R,R)-Threoninol was prepared in one step from l-threonine in 86% isolated yield. The product was regioselectively transformed into 2,2-bis[(4R,5R)-4-(hydroxymethyl)-5-methyl-1,3-oxazolin-2-yl]propane in 42% isolated yield.     

Synthesis,characterization, and structures of copper(I) complexes with N,N′-bis[1-(4-chlorophenyl)ethylidene]ethane-1,2-diamine and N,N′-bis[1-(4-nitrophenyl)ethylidene]ethane-1,2-diamine

Two ligands, N,N′-bis[1-(4-chlorophenyl)ethylidene]ethane-1,2-diamine (L¹ ) and N,N′-bis- [1-(4-nitrophenyl)ethylidene]ethane-1,2-diamine (L² ) and their corresponding copper(I) complexes, [Cu(L ¹)₂]ClO₄ (1) and [Cu(L ²)₂]ClO₄ (2), have been synthesized and characterized by CHN analyses, ¹H-NMR, IR, and UV–Vis spectroscopy. The crystal structures of L¹ and [Cu(L ¹)₂]ClO₄ (1) were determined from single crystal X-ray diffraction. L¹ lies across a crystallographic inversion center and the C=N is approximately coplanar with the benzene ring and adopts E configuration. The coordination polyhedron about copper(I) in 1 is best described as a distorted tetrahedron. Quasireversible redox behavior is observed for the complexes.     

Synthesis,crystal structure and catalytic performance of bis (imino)pyridyl nickel complexes

Two new Ni(II) complexes of 2,6-bis[1-(2,6-diethylphenylimino)ethyl]pyridine (L¹), 2,6-bis[1-(4-methylphenylimino)ethyl]pyridine (L² ) have been synthesized and structurally characterized. Complex Ni(L¹)Cl₂?·?CH₃CN (1), exhibits a distorted trigonal bipyramidal geometry, whereas complex Ni(L¹)(CH₃CN)Cl₂ (2), is six-coordinate with a geometry that can best be described as distorted octahedral. The catalytic activities of complexes 1, 2, Ni{2,6-bis[1-(2,6-diisopropyl-phenylimino)ethyl]pyridine} Cl₂?·?CH₃CN (3), and Ni{2,6-bis[1-(2,6-dimethylphenylimino) ethyl]pyridine}Cl₂?·?CH₃CN (4), for ethylene polymerization were studied under activation with MAO.     

On the chemistry of pyrrole pigments,XCII: Syntheses of 1,2-bis-pyrrolylethanes

Summary 1,2-bis-Pyrrolylethanes are potential synthesis precursors ofb-homorubins. They were synthesized in two ways: by self coupling of a 5-halomethylpyrrole using VCl₃/LiAlH₄ or by the reduction of 1,2-bis-pyrrolylethenes using Mg-MeOH/Pd-C as catalyst. The yields were 30–40% for the first method and reached 80% for the second one.

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Zur Chemie von Pyrrolpigmenten, 92. Mitt.: Synthesen von 1,2-bis-Pyrrolylethanen

Zusammenfassung 1,2-bis-Pyrrolylethane als potentielle Synthesevorstufen vonb-Homorubinen konnten auf zwei Wegen synthetisiert werden. Beim ersten wurden 5-Halogenmethylpyrrole mit VCl₃/LiAlH₄ dimerisiert; der zweite Weg beruht auf der Reduktion von 1,2-bis-Pyrrolylethenen mit Mg-MeOH/Pd-C als Katalysator. Die Ausbeuten betrugen im ersten Fall um 30–40% und erreichten im zweiten Fall 80%.

     

Esters phosphoriques cycliques ou non cycliques de quelques O-isopropylidène-1,2-α-D-pentofurannoses. Communication préliminaire

Cyclic and acyclic phosphate esters of some 1,2-O-isopropylidene-α-D -pentofuranoses When treated with monophenyl phosphorodichloridate, 1,2-O-isopropylidene-α-D -xylofuranose gave the two possible, isolable isomers of the corresponding 3,5-cylic phenylphosphate. Upon phosphorylation of the same sugar derivative using bis (2,2,2-trichloroethyl) phosphorochloridate only one isomer was formed. The same situation obtained when preparing 1,2-O-isopropylidene-α-D -ribofuranose-3,5-cyclic phenylphosphate. The synthesis of a new kind of sugar phosphate with a branched-chain unsaturated sugar moiety namely the trans-3-deoxy-3-C-cyanomethylene-1,2-O-isopropylidene-D -erytho-pentofuranose 5-bis(2,2,2-trichloroethyl) phosphate is also described.     

Synthesis of 1,2- bis (2′-ethynylpyrimidyl) benzene and characterization of the coordination complexes with palladium(II) chloride and silver(I) trifluoromethanesulfonate

Design, synthesis and coordination chemistry of a new trans-coordinating dipyrimidyl ligand are reported. Sonogashira coupling of 2-iodopyrimidine with 1,2-diethynylbenzene yielded the ligand 1,2-bis(2′-ethynylpyrimidyl)benzene (3), in good yield. Coordination complexes were formed with silver(I) and palladium(II) salts. The X-ray crystallographic characterization of the 1?:?1 complex formed between palladium(II) dichloride and 3, and the 4?:?2 complex formed between silver(I) trifluoromethanesulfonate and 3 are reported.     

On the chemistry of pyrrole pigments,XCVI: An efficient synthesis of corrphycenes

Summary By means of copper catalyzed intramolecular coupling of the easily accessible 1,2-bis-(1-iodo-dipyrrin-9-yl)-ethanes and subsequent demetallation of the intermediate copper complexes corrphycenes could be prepared in nearly 40% overall yields.

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Zur Chemie von Pyrrolpigmenten, 96. Mitt.: Eine effiziente Synthese von Corrphycenen

Zusammenfassung Durch Kupfer katalysierte intramolekulare Kupplung der leicht zugänglichen 1,2-bis-(1-Iod-dipyrrin-9-yl)-ethane und anschließende Demetallierung der gebildeten Kupferkomplexe ergibt Corrphycene in Gesamtausbeuten von fast 40%.

     

Synthesis and antiproliferative activity of (1R,2R)-N1-(2-butyl)-1,2-cyclohexanediamine platinum(II) complexes with malonate derivatives

Three new platinum(II) complexes of (1R,2R)-N¹-(2-butyl)-1,2-cyclohexanediamine with malonate derivatives as leaving groups have been synthesized and spectrally characterized. They were tested in vitro against four human cancer cell lines. [(1R,2R)-N¹-(2-butyl)-1,2-cyclohexanediamine-N,N′](2-ethylmalonato-O,O′)platinum(II) turned out to be more active (IC₅₀ = 4.65 μM) than oxaliplatin (IC₅₀ = 6.55 μM) against the MCF-7 cell line and is superior to its parent complex, [(1R,2R)-N¹-(2-butyl)-1,2-cyclohexanediamine-N,N′](malonato-O,O′)platinum(II). In addition, agarose gel electrophoresis study revealed that the interaction of the complex with pET22b plasmid DNA had a different behavior from that of cisplatin or oxaliplatin.     

Oxidative ring-opening of rel-(2R,3R,5S)-5-aryl-2-benzoylamino-6,7-bis(methoxycarbonyl)-2,3-dihydro-1-oxo-3-phenyl-1H,5H-pyrazolo[1,2-a]-pyrazoles. Synthesis of rel-(2R,3R)-3-phenyl-3-[5-aryl-3,4-bis(methoxycarbonyl)pyrazolyl-1]alanine esters

rel-(2R,3R)-N-Benzoylamino-6,7-bis(methoxycarbonyl)-2,3-dihydro-1-oxo-1H,5H-pyrazolot[1,2-a]-pyrazoles 5 , accesible by cycloaddition of dimethyl acetylenedicarboxylate ( 3 ) to (1Z)-rel-(4R,5R)-1-aryl-methylidene-4-benzoylamino-5-phenyl-3-pyrazolidinone-1-azomethine imines 4 , undergo oxidative ring cleavage with methanolic bromine giving rel-(2R,3R)-N-benzoyl-3-phenyl-3-[5-aryl-3,4-bis(methoxy-carbonyl)pyrazolyl-1]alanine methyl esters 6 as products.     

Electrochemical transformations of antimony(V) complexes containing tridentate O,N,O-donor ligands

Electrochemical transformations of antimony(V) complexes containing a tridentate redoxactive ligand, N,N-bis-(2-hydroxy-di-3,5-tert-butylphenyl)amine: R ₃Sb(Cat-NH-Cat) (R = (1) Ph; (2) Et), (3) Et₂Sb(Cat-N-Cat)) are studied. Electrochemical oxidation of complexes 1, 2 occurs irreversibly leading to formation of unstable radical cations. The next stage is the chemical process resulting in formation of neutral paramagnetic compounds. The Et₂Sb(V)(Cat-N-Cat) complex is characterized by two reversible anodic redox processes corresponding to a change of in the ligand redox level. Stable paramagnetic derivatives are formed as a result of electrochemical oxidation of compounds 1, 3; this allows considering these compounds as potential radical scavengers. Interaction of complex 1 with electrogenerated superoxide radical anion led to formation of paramagnetic reaction products.     

SYNTHESIS OF 2′-DEOXY-2′-FLUORO- 1-β-d-ARABINOFURANOSYL URACIL DERIVATIVES: A METHOD SUITABLE FOR PREPARATION OF [18F]-LABELED NUCLEOSIDES

ABSTRACT

N-glycosylation of 2,4-bis-O-(trimethylsilyl)-pyrimidine bases with 2-deoxy-2-fluoro-3,5-di-O-benzoyl-1-(Br, OBz)-α-d-arabinose derivatives are reported. 1-Bromo-arabinose provides high yield and a favorable anomeric ratio (β/α) of pyrimidine nucleoside in either MeCN or CH₂Cl?CH₂Cl. This method should be suitable for the synthesis of 2′-deoxy-2′-[¹⁸F]fluoro-1-β-d-arabinofuranosyluracil derivatives.