Synthesis and Characterization of (Z)-1-[2-(Triarylstannyl)vinyl]-1-Cyclohexanols and their Arylhalostannyl Derivatives

1-Ethynyl-1-cyclohexanol reacts with a triaryltin hydride Ar₃SnH (Ar = phenyl, p-tolyl) and generates the corresponding (Z)-1-[2-(triarylstannyl)vinyl]-1-cyclohexanol. The product obtained reacts with one or two equivalents of halogen (ICl or I₂) to form the associated (Z)-1-[2-(diarylhalostannyl)-vinyl]-1-cyclohexanol or (Z)-1-[2-(aryldihalostannyl)vinyl]-1-cyclohexanol, respectively. All compounds were characterized by elemental analysis, ¹H, ¹³C, ¹¹⁹Sn NMR and Mössbauer spectroscopy.     

Preparation,Isolation and Characterization of all of the Regioisomeric 61, 6N-Bis-O-(Monomethoxytrityl) and-(Dimethoxytrityl) Derivatives of Cyclomalto-Olgosaccharides

Abstract

Regioisomeric 6¹, 6ⁿ-bis-O-(monomethoxytrityl) or 6¹, 6ⁿ-bis-O-(dimethoxytrityl) cyclomaltohexaose, -cyclomaltoheptaose (n = 2-4), and -cyclomaltooctaose derivatives (n = 2-5) were prepared by the reaction of cyclomaltohexaose (1, cG₆, αCD), cyclomaltoheptaose (11, cG₇, βCD) or cyclomaltooctaose (21, cG₈, γCD) and 4-monomethoxytrityl chloride or 4,4′-dimethoxytrityl chloride in pyridine. Products were isolated by HPLC. The regiochemical determination of these positional isomers was done by converting these compounds to the respective 6¹, 6ⁿ-bis-O-(tert-butyldimethylsilyl) derivatives¹ whose structures have been already established.     

Condensation of 2-naphthylamine with aromatic aldehydes and substituted cyclohexane-1,3-diones

New 12-aryl(or hetaryl)-9-methyl(or 4-butoxyphenyl)-8,9,10,12-tetrahydro-7H-benzo[a]acridin-11-ones possessing two asymmetric carbon atoms (C⁹ and C¹²) were synthesized by condensation of 5-methyl-or 5-(4-butoxyphenyl)cyclohexane-1,3-dione with 2-naphthylamine and aromatic or heteroaromatic aldehydes. According to the ¹H NMR data, the products were isolated as mixtures of diastereoisomers.     

Unprecedented and Effective Synthesis of Thiazolines from Perfluoro-3-isothiocyanato-2-methyl-2-pentene and Certain P-Nucleofuges

The reactions of perfluoro-3-isothiocyanato-2-methyl-2-pentene with PPh₃ and P(NEt₂)₃ in the presence of NaBF₄, KI, and NaBPh4 form phosphonium salts with the heterocyclic substituent (4E)-5,5-bis(trifluoromethyl)-4-(tetrafluoroethylidene)-4,5-dihydro-1,3-thiazol-2-yl, instead of involving desulfurization and formation of P-F-containing products. The reaction with tris(pentafluorophenyl)phosphine fails. The reactions with P(OEt)₃ in the presence of ClSiMe₃ or (CH₃O)₂POSiMe₃ yield diethyl or dimethyl [(4E)-5,5-bis(trifluoromethyl)-4-(tetrafluoroethylidene)-4,5-dihydro-1,3-thiazol-2-yl]phosphonates and no intramolecular alkylation products. The ¹H, ¹³C, ¹⁹F, and ³¹P spectra are presented, and the reaction pathways are discussed. Potential mechanisms of the biological and catalytic activity of the reaction products are considered.     

Heteroarenium salts in synthesis. Highly functionalized tetra- and pentasubstituted pyridines

Activation of chloropyridines by heteroarenium substituents allows sequential substitutions by O-, N-, and S-nucleophiles. Reaction of 2,3,5,6-tetrachloropyridine and 4-ethylsulfanyl-2,3,5,6-tetrachloropyridine with 4-(dimethylamino)pyridine, 4-(pyrrolidin-1-yl)pyridine, or 4-aminopyridine results in the formation of 2,6-bis-heteroarenium substituted 3,5-dichloropyridines. On nucleophilic displacement of the heteroarenium substituents by O-, N-, or S-nucleophiles highly functionalized 3,5-dichloropyridines form which possess N²,S⁴,N⁶-, O²,S⁴,O⁶-, O²,O⁶-, N²,N⁶-, and S²,S⁶-substitution patterns.     

Synthesis and mesomorphism behaviour of chalcones and pyrazoles type compounds as photo-luminescent materials

The following organic and organic–inorganic hybrid compounds were prepared as photo-luminescent materials following efficient and practical synthetic methods: 1,3-bis[4-(n-alkoxy)phenyl]-2-propen-1-one (where, n-alkoxy: O(CH₂)_nH, n = 6,7,8,9 or 10); 3,5-bis[4-(n-alkoxy)phenyl]-1H-pyrazole (where, n-alkoxy: O(CH₂)_nH, n = 6,7,8,9 or 10) (in case of n = 7, a mixture of 3,5-bis(4-heptyloxyphenyl)-1H-pyrazole and 3,5-bis(4-heptyloxyphenyl)-4H-pyrazole was detected) and bis(3,5-bis [4-(n-alkoxy) phenyl]-1H-pyrazole) silver(I) nitrate (where, n-alkoxy: O(CH₂)_nH, n = 6,7,8,9 or 10). The prepared compounds have been characterised and their structures were elucidated depending upon (FTIR, UV-Vis, ¹HNMR, ¹³CNMR, 2D ¹H-¹H-COSY, 2D ¹H-¹³C-HSQC and mass spectra) in addition to molar conductivity measurements for silver(I) complexes. The mesomorphism behaviour of the prepared compounds was studied using polarised light optical microscopy and confirmed with differential scanning calorimetry and X-ray powder diffraction techniques. The studies showed that among all of these compounds only the pyrazole derivatives are liquid crystal materials. The luminescent properties of all the prepared compounds were also investigated which confirmed that all of these compounds are photo-luminescent in the crystalline solid state and in the mesophase.     

On the incorporation of geraniol and farnesol into cantharidin (author's transl)

On the incorporation of geraniol and farnesol into cantharidin Earlier investigations [1] have shown that cantharidin (1) is biosynthesized by the male Lytta vesicatoria L. (Meloidae, Coleoptera) from the common terpenoid precursors mevalonate and farnesol (3) . To prove if geraniol (2) is incorporated via farnesol (3) into cantharidin (1) the following geraniols have been synthesized and injected into either larvae or male adult Lytta vesicatoria, partly in a mixture with synthetic 11′, 12-[³H]-farnesol as an internal standard: 2-[¹⁴C]-, 7-[¹⁴C]-, 7′, 8-[¹⁴C]-, 7′, 8-[³H]-geraniol. Unexpectedly, geraniol (2) was not specifically incorporated into cantharidin (1) perhaps due to its higher toxicity or its faster degradation relative to the other precursors before incorporation. The incorporation of U-[¹⁴C]-leucine, U-[¹⁴C]-isoleucine and 1-[¹⁴C]-glucose into cantharidin (1) via their metabolites is evident by degradation studies, whereas 1-[¹⁴C]- and 2-[¹⁴C]-glycine do not serve as precursors for cantharidin (1) .     

Synthesis and Metal-Binding Properties of Polybipyridine Ligands Derived from Acyclic and Macrocyclic Polyamines

Synthetic procedures have been developed for the preparation of ligands bearing two to six pendent, unsubstituted or substituted 2, 2′-bipyridine groups attached to acyclic (tripode, tetrapode) and macrocyclic (triazanonade-cane, cyclam, hexacyclen, bis(bipyrido)hexaazamacrocycle) polyamines. Ligands 1-5 have been obtained in high yield by condensation of 6-(bromomethyl)-2, 2′-bipyridine ( 9b ) with the corresponding amines in the presence of NaOH, H₂O, and MeOH. Ligands 6-8 have been prepared in good yield by condensation of 9b or the di- or tetrasubstituted mono (bromomethyl) bipyridine 10b or 11b , respectively, with the corresponding amines in the presence of Na₂CO₃ and MeCN. Ligand 1 forms hemi-cage complexes with Ru^II, Fe^I, Cr^II, and Cr^III cations and trinuclear complexes with [RuCl²(bpy)²] and [ReCl(CO)⁵]. Tetrapode 2 and hexapode 4 gave tetranuclear and dinuclear complexes, respectively, by reaction with Fe11 salts. These complexes possess a variety of interesting physical and chemical properties.     

Ni(dmit)2 salts with chiral stilbazolium- and ferrocenyl-based chromophores as countercations

Four 1:1, two-component salts combining the [Ni(dmit)₂]⁻ anion (dmit²⁻ = 2-thioxo-1,3-dithiole-4,5-dithiolato) and chiral stilbazolium-based countercations (HPMS⁺ = 4′-[2-(hydroxymethyl)pyrrolidinyl]-1-methylstilbazolium and MPMS⁺ = 4′-[2-(methoxy-methyl)pyrrolidinyl]-1-methylstilbazolium), or chiral ferrocenyl-based countercations (2⁺ = (E)-1-((R)-2-methylferrocenyl)-2-(1-methyl-4-pyridiniumyl)ethene; 3⁺ = (E)-1-((S)-2-trimethylsilylferrocenyl)-2-(1-methyl-4-pyridiniumyl)ethene) were prepared. Semiconducting behaviour (2·10⁻⁴ S·cm⁻¹ measured on compressed pellets for [Ni(dmit)₂] (MPMS), for example) is secured by the presence of the [Ni(dmit)₂]⁻ anions. The chiral nature of the countercations ensures non-centrosymmetry of the structures (space group P1 for [Ni(dmit)₂](2) and [Ni(dmit)₂](3), for example). A ubiquitous antiparallel arrangement of the cations, which are thus packed in a pseudo-centrosymmetrical environment, results in almost vanishing second-order susceptibilities χ⁽²⁾, and therefore zero efficiencies in second harmonic generation.     

Fe3+和Fe2+对原代培养的成骨细胞增殖、分化和矿化功能的影响

采用噻唑蓝(MTT)法、碱性磷酸酶(ALP)比活性测定、油红O染色和茜素红染色及定量分析,研究了不同浓度的Fe3+和Fe2+对原代培养的成骨细胞增殖、分化及矿化功能的影响.结果表明:浓度为1×10-9～1×10-4 mol·L-1的Fe3+和Fe2+促进成骨细胞增殖,但是在较高浓度1×10-3 mol·L-1时,它们则抑制成骨细胞增殖.与成骨细胞作用48 h,浓度为1×10-8～1×10-4 mol·L-1的Fe3+和Fe2+抑制其分化,但在较低的浓度1×10-9 mol·L-1时则对其分化没有影响:进一步延长作用时间为72 h,Fe3+对成骨细胞分化没有影响,除1×10-6mol·L-1浓度的Fe2+促进成骨细胞分化外,其他浓度的Fe2+则抑制其分化;测试浓度下的Fe3+对成骨细胞向脂肪细胞的横向分化表现为抑制或没有影响,而Fe2+的影响则依赖于浓度和作用时间.在1×10-8～1×10-5mol·L-1浓度范围内,Fe3+和Fe2+对矿化结节的影响表现出相反的效应.在较高浓度(1×10-4mol·L-1)下,它们促进矿化节结的形成,而在较低浓度(1×10-9mol·L-1)下,Fe3+抑制矿化节结的形成,Fe2+则没有影响.结果提示:浓度.作用时间和铁离子的价态都是影响Fe3+和Fe2+生物效应(从毒性到活性,从损伤到保护,从上调到下调)转变的关键因素.     

Regioselective Reaction of N1-Benzyl-N2-(4-nitrophenyl)ethanediamide and Acetylenic Esters

The regioselective reaction of N¹-benzyl-N²-(4-nitrophenyl)ethanediamide with dialkyl acetylenedicarboxylates or alkyl propiolates in the presence of triphenylphosphine leads to dialkyl 4-benzylamino-1-(4-nitrophenyl)-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates or alkyl 4-benzylamino-1-(4-nitrophenyl)-2-oxo-5-pyrrolidinecarboxylates in good yields.     

Synthesis and physico-chemical studies of novel mixed-ligand cyanonitrosyl {CrNO}5 complexes of chromium with benzyl-, benzoyl- and acetyl-pyridines

Summary Novel mixed-ligand cyanonitrosyl complexes of chromium(I), [Cr(NO)(CN)₂(L)₂(H₂O)], (where L=2-, 3-, or 4-benzylpyridine, 2-(4-chlorobenzyl)pyridine, 2-, 3-, or 4-benzoylpyridine, 3-(4-methylbenzoyl)pyridine, or 2-, 3-, or 4-acetylpyridine) have been prepared by the interaction of potassium pentacyanonitrosylchromate(I) monohydrate, K₃[Cr(NO)(CN)₅]·H₂O with L. The complexes, characterized by elemental analyses, magnetic measurements, e.s.r. and i.r. spectral studies, contain chromium(I) in a low-spind ⁵-configuration. An octahedral structure, where CN istrans to CN, L istrans to L, and NO istrans to water is proposed for all the complexesEnemark and Feltham⁽¹⁾ have proposed circumventing the problem of the non-innocent nature of the nitrosyl ligand by considering nitrosyls as containing the {MNO} ⁿ group, wheren is the number of electrons of M, plus the number of electrons in the ^*-orbital of the NO (or more convenientlyn is the number of d-electrons if nitrosyl is regarded as being coordinated as NO⁺)     

Synthesis of All Four Stereoisomers of (E)-Vitamin KT (Phylloquinone), Analysis of Their Diastereoisomeric and Enantiomeric Purities and Determination of Their Biopotencies

All four stereoisomers of (E)-vitamin Kb i. e. (2¹E, ⁷R, 11¹R)-l (= 1a), (2¹E, 7¹ R, l1¹S)-1 (= 1b), (2¹E, 7¹ S, 11¹S) 1 ( = 1c), and (2¹E, 7¹S, 11¹R)-l ( = Id), have been synthesized in a state of high chemical and stereoisomeric purity. The synthesis of stereoisomers lb-d relied on the use of the optically active Cf¹* and C*¹⁰-building blocks (R)- or (S)-4-(benzyloxy)-3-methylbutanal ((R)- or (S)-2) and (R)- or (S)-citronellal ((R)- or (S)- 3 ) which had been secured by the Rh¹-catalyzed allylamine-to-enamine isomerization technology. For the synthesis of the natural (E)-vitamin-K1 stereoisomer 1a , a new route starting from natural phylol was developed, based on an O-alkylation/rearrangement procedure. A HPLC method was developed which separates with remarkable efficiency all four stereoisomers of (E)- as well as three out of the four stereoisomers of (Z)-vitamin K¹ on optically active poly(trityl methacrylate) as the chiral stationary phase supported on Nucleosil. By this method, the stereoisomeric content of the stereoisomers 1b-d synthesized was shown to be in the range of 96-98 %, while the natural isomer 1a was configurationally uniform. The biological activity of the four (E)-vitamin-K₁ stereoisomers was determined by means of the curative prothrombin time test with vitamin-K-depleted chicks. A high precision of the results was obtained with the recently introduced up-and-down organization of the test and the statistical evaluation according to an estimation procedure. With the natural (E)-vitamin-K₁ stereoisomer 1a as standard (set at 1. 0), activities of 0. 93, 1. 19, and 0. 99 were found for stereoisomers 1b, 1c , and 1d , respectively. Within the confidence limits, these activity ratios can be regarded as identical, A very similar efficacy was obtained by comparison of (E, all-rac )-vitamin K₁ ((2¹E, RS, 11′ RS)- 1 ; equimolar mixture of the four stereoisomers 1a-d) with the natural (E)-vitamin-K₁ stereoisomer 1a ). A synergistic effect was not detectable, as was the case with the eight α-tocopheryl-acetate stereoisomers.     

Spectrophotometric and fluorimetric determinations of trichothecene mycotoxins with reagents for formaldehyde

Several trichothecene mycotoxins, such as fusarenone-X (F-X) and T-2 toxin (T-2), readily liberate formaldehyde on heating with sulfuric acid. Spectrophotometric and fluorimetric methods for the determination of trichothecenes with reagents for formaldehyde are therefore possible. F-X (or T-2) can be determined in the 50–1000 mg l^-1 (or 50–1500 mg l^-1) range by the chromotropic acid method, in the 30–1200 mg l^-1 (or 50–2000 mg l^-1) range by the phenyl J acid method, and in the 1.25–25 mg l^-1 (or 2–40 mg l^-1) range by the J acid method. Other trichothecenes, neosolaniol, nivalenol, tetraacetylnivalenol, diacetoxyscirpenol and HT-2 toxin, etc. also give positive reactions but trichothecin and dihydronivalenol do not.     

Synthesis,characterization, and electrochemical study of two new macroacyclic Schiff bases and their copper(II) and zinc(II) complexes

Two new potentially octadentate N₂O₆ Schiff-base ligands 2-((E)-(2-(2-(2-((E)-2-hydroxy-3-methoxybenzylideneamino)phenoxy)phenoxy)phenylimino)methyl)-6-methoxyphenol H₂L¹ and 2-((E)-(2-(2-(2-((E)-2-hydroxy-3-methoxybenzylideneamino)phenoxy)-4-tert-butylphenoxy)phenylimino)methyl)-6-methoxyphenol H₂L² were prepared from the reaction of O-Vaniline with 1,2-bis(2′-aminophenoxy)benzene or 1,2-bis(2′-aminophenoxy)-4-t-butylbenzene, respectively. Reactions of H₂L¹ and H₂L² with copper(II) and zinc(II) salts in methanol in the presence of N(Et)₃ gave neutral [CuL¹]?·?0.5CH₂Cl₂, [CuL²], [ZnL¹]?·?0.5CH₂Cl₂, and [ZnL²] complexes. The complexes were characterized by IR spectra, elemental analysis, magnetic susceptibility, ESI–MS spectra, molar conductance (Λ_m), UV-Vis spectra and, in the case of [ZnL¹]?·?0.5CH₂Cl₂ and [ZnL²], with ¹H- and ¹³C-NMR. The crystal structure of [ZnL¹]?·?0.5CH₂Cl₂ has also been determined showing the metal ion in a highly distorted trigonal bipyramidal geometry. The electrochemical behavior of H₂L² and its Cu(II) complex, [CuL²], was studied and the formation constant of [CuL²] was evaluated using cyclic voltammetry. The logarithm value of formation constant of [CuL²] is 21.9.     

Synthesis and structure of nitroethylpyrrolidone carboxylates

3-Methoxycarbonyl-4-phenyl- and 4-(3-pyridyl)-2-pyrrolidones react with 2-aryl(heteryl)-1-nitroethenes to form C³-adducts as one or two diastereomers. Their structure was characterized by the IR, ¹H, and ¹³C NMR spectroscopy, using the two-dimensional correlation spectroscopy.     

A stereo- and regio-specific addition of η3-trimethylsilylallyltitanium compound with aldehydes. A facile and stereocontrolled synthesis of E- and Z-terminal dienes

η³-Trimethylsilyallyltitanium compound, (η⁵-C₅H₅)₂Ti(η³-1-trimethylsilylallyl), reacts with aldehydes to give (±)-(R,S)-3-trimethylsilyl-4-hydroxy-1-alkenes in excellent yields, which can be deoxysilylated to either E- or Z-1,3-dienes.     

8-Aza-7-deazaadenine N8- and N8-(β-D-2′-Deoxyribofuranosides): Building blocks for automated DNA synthesis and properties of oligodeoxyribonucleotides

Oligonucleotides with alternating 8-aza-7-deaza-2′-deoxyadenosine (= c⁷z⁸A_d2) and dT residues (see 11, 14 and 16 ) or 4-aminopyrazolo [3,4-d] pyrimidine N²-(β-D -2′-deoxyribofuranoside) (= c⁷z⁸A′_d¹); ( 3 ) and dT residues (see 12 ) have been prepared by solid-phase synthesis using P(III) chemistry, Additionally, palindromic oligomers derived from d(C-T-G-G-A-T-C-C-A-G) but containing 2 or 3 instead of dA (see 18 – 22 ) have been synthesized. Benzoylation of 2 or 3 , followed by 4,4′-dimethoxytritylation and subsequent phosphitylation yielded the methyl or the cyanoethyl phosphoramidites 8a,b and 9 . They were employed in automated. DNA synthesis. Alternating oligomers containing 2 or 3 showed increase dT_m values compared to those with dA, in particular 12 with an unusual N²-glycosylic bond. The palindromic oligomers 18 - 22 containing 2 or 3 instead of dA outside of the enzymic recognition side reduced the hydrolysis rate, replacement within d(G-A-T-C) abolished phosphodiester hydrolysis.     

A short and efficient synthesis of N-aryl- and N-heteroaryl-N-(arylalkyl)piperazines

A new synthesis of N-aryl- and N-heteroaryl-N^′-(arylalkyl)piperazines using palladium-catalyzed amination of aryl bromides and heteroaryl chlorides with mono N-benzyl- or N-(arylethyl)piperazines is reported. Most coupling processes proceed in high yield and good selectivity using either diadamantyl-n-butylphosphine (1), 2-(dicyclohexylphosphino)-2^′-(N,N-dimethylamino)biphenyl (2), or 2-(di-tert-butylphosphino)biphenyl (3) as ligand. Applying an automated parallel synthesizer the preparation of a small library of potentially bioactive compounds is easily achieved.     

Design and synthesis of 2-substituted-8-hydroxyquinline zinc complexes with hole-transporting ability for highly effective yellow-light emitters

Four multifunctional 8-hydroxyquinoline derivatives were designed and synthesized, their structures were identified by FT-IR, ¹H NMR, MS and elemental analysis. Among them are (E)-2-(2-(9-(4-methoxyphenyl)-9H-carbazol-3-yl)vinyl) quinolato-zinc (1), (E)-2-(2-(9-p-tolyl-9H-carbazol-3-yl)vinyl)quinolato-zinc (2), (E)-2-(2-(9H-fluoren-2-yl)vinyl)quinolato-zinc (3), and (E)-2-(2-(phenanthren-9-yl)vinyl)quinolato-zinc (4). The electroluminescence (EL) and hole-transporting characteristics of these materials were investigated on four configurations: (A) ITO/2-TNATA/NPB/1, 2, 3 or 4/Alq₃/LiF/Al; (B) ITO/2-TNATA/NPB/1, 2, 3 or 4/LiF/Al; (C) ITO/2-TNATA/1, 2, 3 or 4/Alq₃/LiF/Al; and (D) ITO/2-TNATA/1 or 2/NPB/Alq₃/LiF/Al. The maximum luminescence and current efficiencies of are 3556 cd m⁻² (at 13 V) and 2.17 cd A⁻¹ (at 9 V) for compound 2, 4624 cd m⁻² (at 15 V) and 2.1 cd A⁻¹ (at 7 V) for compound 3, and 3164 cd m⁻² (at 14 V) and 1.83 cd A⁻¹ (at 13 V) for compound 4 in the configuration D, respectively, indicating that they are good multifunctional materials with strong hole-transporting abilities and luminescence properties.