Compounds A2 Research Articles

Effects of Different Terminal Substituents on the Mesomorphic Behavior of Some Azo-Schiff Base and Azo-Ester-Based Liquid Crystals

In order to investigate the influence of the terminal substitution on mesomorphism, two new series of azo-Schiff base and azo-ester liquid crystals having the following structures have been synthesized. All the compounds possess mesomorphic properties. In series A compounds A1 and A3 exhibit only a nematic mesophase, whereas compounds A2, A4, A5, A6, A7, A8, A9, and A10 exhibit a smectic as well as a nematic phase. In series B compounds B1 to B9 exhibit only a nematic mesophase, and compounds B10 and B11 exhibit a smectic as well as a nematic phase, but compound B12 exhibits only a smectic phase. All these compounds were characterized by elemental analyses and spectroscopic techniques (Fourier transform infrared [FTIR], 1H nuclear magnetic resonance [NMR], and mass spectroscopy). Their mesomorphic properties were measured by optical polarized light microscopy and differential scanning calorimetry (DSC).

Cyanoplatinate Halides – Synthesis, Crystal Structure Analyses and Vibrational Spectroscopy of Compounds A2[Pt(CN)4X2] (A = Rb, Cs; X = Cl, Br, I)

Crystal structures of the cyanoplatinates A2[Pt(CN)4X2] (A = Rb, Cs; X = Cl, Br, I) have been determined by single-crystal analysis and X-ray powder diffraction. The compounds were synthesized by metathesis from Ba[Pt(CN)4] ·4 H2O and alkali metal sulfates, and by subsequent oxidation with the respective halogens. The crystals were grown by slowly concentrating respective aqueous solutions. The PtIV cations are octahedrally coordinated by four cyanide ligands and two halogen atoms, the latter being located in trans positions. Rb2[Pt(CN)4Cl2]: triclinic, P¯1 (Z = 2), a = 6.7779(2), b = 9.3149(3), c = 9.6707(3) Å , α = 89.37(0), β = 76.05(0), γ = 72.98(0)◦, V = 565.42(2) Å3, N` hkl= 5616, R(F)N` = 0.0273; Rb2[Pt(CN)4I2]: monoclinic, P21/c (Z = 2), a = 7.4239(2), b = 9.2486(2), c = 9.1189(2) Å , β = 107.22(3)◦, V = 598.04(6) Å3, N` hkl = 2917, R(F)N` = 0.0295; Cs2[Pt(CN)4I2]: monoclinic, P21/c (Z = 2), a = 7.6740(4), b = 9.5397(5), c = 9.3474(5) Å , β = 106.46(0)◦, V = 656.3(2) Å3, Z = 2, N` hkl = 2738, R(F)N` = 0.0283; Cs2[Pt(CN)4Cl2]: monoclinic, C2/c (Z = 4), a = 17.947(4), b = 7.395(2), c = 12.031(3) Å , β = 131.904(1)◦, V = 1188.4(5) Å3, R-wp = 2.77; Cs2[Pt(CN)4Br2]: monoclinic, C2/c (Z = 4), a = 18.404(1), b = 7.2819(5), c = 12.4156(8) Å , β = 132.156(1)◦, V = 1233.5(1) Å3, N` hkl = 2566, R(F)N` = 0.0268. All compounds were characterized by differential thermal analysis, thermogravimetry, and infrared and Raman spectroscopy.

A New Example of the Structure Type A2[{Z2R4}X9]: Synthesis and Crystal Structure of Na2[{(ON)Ce4}Cl9

AbstractFirst single crystals of Na2[{(ON)Ce4}Cl9] were obtained during synthesis attempts for the cerium nitride chloride Ce2NCl3(= {N2Ce4}Cl6). With a molar ratio of 8:10:3 for Ce, CeCl3 and NaN3 along with an excess of the flux NaCl, the mixture obviously contained a small amount of CeOCl that led to the formation of quinary Na2[{(ON)Ce4}Cl9]. It crystallizes in the monoclinic space group P21/m(no. 11) with two formula units in the unit cell with dimensions of a = 813.21(6) pm, b = 1146.13(9) pm, c = 942.86(7) pm and β = 107.504(5) °. As the dominating structural feature {ZCe4}9.5+ tetrahedra are fused through trans‐oriented edges to generate ${}^1_\infty\{\textit{Z}\textrm{Ce}^\textrm{e}_{4/2}\}^{3.5+}$ chains (Z = 1/2 O + 1/2 N) just as in the structurally isotypic compounds A2[{Z2R4}X9] (A = Na, K; R = Pr, Nd, Gd; X = Cl, Br; Z = O, O/N).

Synthesis and Evaluation of 1,3 Di-Substituted Schiff, Mannich Bases and Spiro Isatin Derivatives

Schiff bases of isatin with aminothiazole, its N-mannich bases and Spiro isatin derivatives were synthesized. Their chemical structures were confirmed by Infrared, 1H-Nuclear Magnetic Resonance data and elemental analysis. Antimicrobial evaluation was performed by the agar diffusion method against four pathogenic bacteria and two pathogenic fungi. Anti-inflammatory activity was tested by carragenin-induced rat paw edema and compounds were evaluated for analgesic action by the acetic acid-induced writhing method; Compounds Aa, Ab and A5, A6 were found to be active against bacteria and fungi. The compounds A3, A6, Aa and Ab showed anti-inflammatory activity, having a percentage protection value of 34.69, 32.65, 38.77 and 36.73 as compared with that of indomethacin, with % protection of 46.93. Similarly, the compounds Aa, Ab and A6 showed analgesic activity, with % protection of 67.51, 64.78 and 49.81 as compared with the standard with % protection of 79.56.

Synthesis and properties of colored copper-containing alkaline-earth phosphates with an apatite structure

Colored compounds A5(PO4)3Cu0.1OHz, where A = Ba1-xSrx (x=0,0.5,0.8), Sr1-y Cay (y=0,0.2, 0.5, 1), and Ba1/3Sr1/3Ca1/3 with an apatite structure containing copper ions in the hexagonal channels have been synthesized by the thermal treatment of the corresponding carbonates, oxides, and ammonium hydrophosphate at 1150°C. The use of the composition with A = Ba0.5Ca0.5 gives a multiphase product containing apatite (Ba1-xCax)5(PO4)3CuyOHz with x ∼ 0.2 as the major phase. The hexagonal lattice parameters of apatite depend linearly on the content of solid solution in the alkaline-earth metals. In the series of A = Ba, Ba-Sr, Sr, Sr-Ca, and Ca, the color of the samples changes smoothly from blue through violet to pink, whereas the samples with A = Ba0.5Ca0.5 and Ba1-3Sr1-3Ca1-3 are light gray. The diffuse reflectance electronic spectra exhibit two absorption bands characteristic of the copper ions in the hexagonal channels. Their positions depend on the alkaline-earth metal content of the compound. The third characteristic band appears in the spectrum of calcium apatite. Its relative intensity increases when calcium is gradually replaced by strontium and especially by barium, which results in worsening and even loss of the sample color. These spectral changes are presumably due to the transition of some copper ions from the hexagonal channels to other positions of the crystal lattice.

Nematodetoxic Aurovertin-Type Metabolites from a Root-Knot Nematode Parasitic FungusPochonia chlamydosporia

Chemical investigation of one fungal strain P. chlamydosporia YMF 1.00613 isolated from root knots of tobacco infected by Meloidogyne incognita led to the isolation and identification of four aurovertin-type metabolites, which include a new compound, aurovertin I (A1), and three known metabolites, aurovertins E, F and D (A2-A4). Their structures were established by spectroscopic studies such as 1D- and 2D-NMR and MS analysis. Aurovertin I (A1) is the first natural product with an aurovertin skeleton with one less carbon. Compounds A3 and A4 showed the toxicity to the worms of the free-living nematode Panagrellus redivevus with the LC(50) values 88.6 and 41.7 microg/mL at 48 h, respectively. All four aurovertins did not show obvious inhibitory effects on egg hatch of root knot nematode Meloidogyne incognita. The results suggested that the aurovertin-type metabolites produced by P. chlamydosporia might be one of the pathogenic factors involved in the suppression of nematodes.

Self-assembly based on heterotriangulene derivatives: from nanowires to microrods

Compound SA-6, SA-8 and SA-10 (totally called SAs) were synthesized by palladium-catalyzed Sonogashira cross-coupling reactions of core derivative 3 with three equiv. of 1-alkyloxy-4-ethynylbenzene 2 in good yields. After the dichloromethane solutions of SAs were mixed with methanol, two-level self-assemblies from nanowires to microrods based on SAs were obtained and characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The driving force of the two-level self-assembly is attributed to the strong π–π stacking ability of heterotriangulene cores and the hydrophobic interactions of alkyl chains with solvent molecules. These two processes may well be used for other molecules to fabricate new nanomaterials in the field of photoelectric devices.

Synthesis, structure characterization, and biological evaluation of some new 1,2,3-benzotriazole derivatives

Ten novel benzotriazole compounds were synthesized. Their chemical structures were confirmed by 1H NMR, IR, and elemental analyses, coupled with three selected single-crystal structures (compounds A2, B3, and B5). Their antimycotic and antitumor activities were also investigated. The title compounds showed some antitumor activities, especially in the case of A3 and A4, which showed the most potent activity of propagation inhibition in liver and galactophore cancer cells.

New compounds A 3 + Te6+M 3 3+ X 2 5+ O14 (A = Na, K; M = Ga, Al, Fe; X = P, As, V) with the Ca3Ga2Ge4O14 structure

Compounds A3+Te6+M33+X25+O14 (A = Na, K; M = Ga, Al, Fe; X = P, As, V) with the Ca3Ga2Ge4O14 structure (sp. gr. P321) were prepared by solid-phase synthesis at 600–850°C in air. The compounds melt incongruently or decompose in the solid state.

Novel aminopeptidase N inhibitors derived from antineoplaston AS2–5 (Part II)

As our ongoing work, a series of peptidomimetic l- iso-glutamine derivatives derived from antineoplaston AS2–5 scaffold were prepared and their APN/CD13 and MMP-2 inhibitory activities were evaluated hereby. The results displayed that these compounds exhibited selective inhibition against APN as compared with MMP-2, with IC 50 values in micromole range. Compounds A1 and A2 showed comparable APN inhibitory activities than the positive control bestatin.

Antihistamine Activities of Iminodiacetamide Derivatives

A series of N,N'-substituted iminodiacetamide derivatives was synthesized and evaluated their inhibitory effects on the histamine-induced smooth muscle contraction in guinea-pig ileum and on the histamine release from IgE-sensitized RBL-2H3 cells (rat basophilic leukemia cell line). Compounds A3, A4 and A5 which have 1-(4-chlorobenzhydryl) piperazine moiety, showed both moderate antihistamine activity and histamine release inhibitory activity.

Anthelmintic activity of benzimidazole derivatives against Toxocara canis second-stage larvae and Hymenolepis nana adults

The anthelmintic activity of 11 benzimidazole derivatives (A1–A11) and 2 thioureides N, N′-disubstituted (B1–B2) was determined. Each compound and albendazole was tested in vitro against Toxocara canis larvae and in vivo against Hymenolepis nana adult. Compounds A1–A6 and B1–B2 were designed as albendazole prodrugs. Compounds A8–A11 were designed as direct analogues of A7, which had previously proved to be an effective agent against Fasciola hepatica. Results of the in vitro screening showed that A6 was more active than albendazole at 0.18 μM (relative mobility 40% and 80%, respectively). Whereas that the in vivo evaluation against H. nana, compounds A7–A11 demonstrated significant activity in terms of removing cestode adults in the range of 88–97%, displaying better efficacy than albendazole (83%).

Purification of bioactive natural product against human microbial pathogens from marine sea weed Dictyota acutiloba J. Ag.

Herbal extracts play an essential role in treating various diseases. The threats in drug resistant pathogenic microbial strains can be prevented by the un-tapped medicinal principles from plants. The present study has been focused to search for powerful antimicrobial natural products from Dictyota acutiloba J. Ag. against human enteric pathogens and dermatophytic fungi. Chloroform and acetone extracts of Dictyota acutiloba exhibited antimicrobial activity against methicillin resistant Staphylococcus aureus (MRSA), methicillin susceptible Staphylococcus aureus (MSSA), Enterobacter sp., Pseudomonas aeruginosa MTCC741, Salmonella typhi MTCC733, Bacillus subtilis, Klebsiella pneumoniae MTCC109, Candida albicans and Aspergillus niger MTCC281. Purified compounds A1 and C1 by column chromatography, TLC and HPLC inhibited the gram positive, gram negative bacteria and fungi. MIC of C1 and A1 ranged between 0.5 and 0.9 μg ml−1. The absorption maximum of C1 and A1 was 355 nm. Structural characterization of these purified molecules can lead to the new therapeutic molecule to fight the pathogenic microorganisms.

Condensation reaction of benzil with resorcinol and the establishment of the spectral data as well as cytotoxicity study

Condensation of benzil, 1 with resorcinol in the presence of potassium carbonate at 110-120°C gave the mixture of the compounds. Using various kinds of separation technique only five types of the polymeric products, a1, a2, a3, a4 and a5 were isolated. The compounds a1, a4 showed high cytotoxic activity and the compounds a2, a3 and a5 showed relatively low cytotoxic activity against the brine shrimp lethality bioassay.

Synthesis and Anti-bacterial Properties of Mono-carbonyl Analogues of Curcumin

The synthesis of three series of curcumin analogues with mono-carbonyl is described. Their in vitro anti-bacterial activities against seven Gram-positive and Gram-negative bacteria were tested and the effect of substituents on the aryl ring and the space structure of the linking strain were discussed. It was observed that part of the derivatives displayed significant activity when compared with curcumin and most of them exhibited activity against the ampicillin-resisted Enterobacter cloacae. Compounds A12, B09, B13, B14 and C09 show remarkable antibacterial activity in vitro. The result showed that heterocycle or long-chain substituents may enhance the activity of curcumin analogues.

Synthesis and Pharmacological Investigation of 3‐Subsituted‐amino‐2‐methylsulfanyl‐5,6,7,8‐tetrahydro‐3H‐benzo[4,5]thieno[2,3‐d]pyrimidin‐4‐ones as Analgesic and Anti‐Inflammatory Agents

In the present work, design, synthesis, and pharmacological evaluation of the analgesic, anti-inflammatory, and ulcerogenic-index activities of new 3-subsituted-amino-2-methylsulfanyl-5,6,7,8-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-ones, structurally planed by exploiting a clear concept of bio-isosterism, are reported. All compounds exhibited significant analgesic and anti-inflammatory activity. Compounds A1, A3 showed higher analgesic activity and more potent anti-inflammatory activity than that of the reference compound diclofenac sodium. Interestingly, the test compounds showed only mild ulcerogenic potential when compared to that of acetylsalicylic acid.

Theoretical studies of ethylene addition to transition metal compounds with carbene and oxo groups LnM(CH2)(O)

AbstractQuantum chemical calculations using density functional theory at the B3LYP level in combination with relativistic effective core potentials for the metals and TZ2P valence basis sets have been carried out for elucidating the reaction pathways of ethylene addition to MeReO2(CH2) (C1). The results are compared with our previous studies of ethylene addition to OsO2(CH2)2 (A1) and OsO3(CH2) (B1). Significant differences have been found between the ethylene additions to the osmium compounds A1 and B1 and the rhenium compound C1. Seven pathways for the reaction C1+C2H4 were studied, but only the [2+2]Re,C addition yielding rhenacyclobutane C5 is an exothermic process with a high activation barrier of 48.9 kcal mol−1. The lowest activation energy (27.7 kcal mol−1) is calculated for the [2+2]Re,C addition, which leads to the isomeric form C5′. Two further concerted reactions [3+2]O,C, [3+2]O,O, and [2+2]Re,O and the addition/hydrogen migration of ethylene to one oxo ligand are endothermic processes which have rather high activation barriers (>35 kcal mol−1). Four isomerization processes of C1 have very large activation energies of >65 kcal mol−1. The ethylene addition to the osmium compounds A1 and B1 are much more exothermic and have lower activation barriers than the C2H4 addition to C1. Copyright © 2007 John Wiley & Sons, Ltd.

THERMODYNAMIC PARAMETERS OF INHIBITION OF ALUMINUM DISSOLUTION IN OXALIC ACID SOLUTIONS USING SOME ORGANIC COMPOUNDS

Corrosion of aluminum in oxalic acid has been done by using wt-loss technique and polarization technique in presence of different concentrations of different organic derivatives of (5-Acetyl, 3-Cyano, 6-Methyl, 2-Thiopyridone, …) such as (…, 4-p Anisyl [A1]), (…,4-p Bromo phenyl [A2]), (…, 4-p Tolyl, [A3]), (…,4-p Nitro phenyl [A4]) and (…,4-p Chloro phenyl [A5]) at different temperatures. It is noticed from the observed thermodynamic parameters derived from wt-loss measurements that ∆H for the adsorption of A1, A2, A3 and A5 resulted in a negative value (exothermic), the adsorption typed is chemical adsorption, whereas A4 acquired physical adsorption and accelerated the dissolution of aluminum. This behavior is also observed at high temperatures for A5 compound. From the polarization method studied the dissolution of aluminum in oxalic acid is decreasing as the concentration of the acid increased due to the formation of oxide passive layer (Al2O3. 3H2O), the application of Evans diagram showed that the used compounds A1, A2, A3 and A5 can act as anodic inhibitors.

Solid-phase synthesis and pharmacological evaluation of a library of peptidomimetics as potential farnesyltransferase inhibitors: an approach to new lead compounds

Oncogenic Ras proteins whose activation is farnesylation by farnesyltransferase have been seen as important targets for novel anticancer drugs. Inhibitors of this enzyme have already been developed as potential anti-cancer drugs, particularly by rational design based on the structure of the CA 1A 2X carboxyl terminus of Ras. Synthesis of a peptidomimetics library via solid-phase synthesis using the Multipin TM method is described here. The most active hits on cellular assays were resynthesized and enzymatic activity was measured. Compounds A1, A5 and A7 present significant activity on the isolated enzyme (IC 50 = 117, 57.3 and 28.5 nM) and their molecular docking in the active site of the enzyme provides details on key interactions with the protein.

Synthesis and evaluation of novel 8-oxo-8H-cyclopenta[a]acenaphthylene-7-carbonitriles as long-wavelength fluorescent markers for hypoxic cells in solid tumor

Novel bioreductive and long-wavelength fluorescent markers for hypoxic cells in solid tumor, 9-isocyano-8H-acenaphtho[l,2-b]pyrrol-8-one with the side chain of 2-nitroimidazole, were designed, synthesized, and evaluated in V79 379A Chinese hamster cells in vitro. Compounds A2 and A4 showed good hypoxic–oxic fluorescence differential in vitro (V79 cells) by using fluorescence scan ascent.