Antimicrobial activity of the methanolic bark extract of Holarrhena pubescens (Buch. Ham), its fractions and the pure compound conessine

The antimicrobial activity of the methanolic extract of the bark of Holarrhena pubescens, its fractions, and conessine, a steroidal alkaloid, was determined against various bacteria and fungi using the agar diffusion method. They were all found to possess significant activity against some of the bacteria tested. The alkaloidal fraction and conessine also exhibited marginal activity against some of the fungi tested. The minimum inhibitory concentration (MIC) value of conessine was determined against various bacteria, and the highest activity was seen against Micrococcus luteus ATCC 9341 (MIC: 15.6?μg per disc).     

Synthesis and Crystal Structure of Bis[O,O'-di(2-phenylethyl)dithiophosphato](α,α'-bipyridine)copper(Ⅱ)

A ternary adduct Cu[S2P(OCH2CH2Ph)2]2·bipy(bipy=α,α'-bipyridine) was syn-thesized and characterized by elemental analysis,IR and single-crystal X-ray diffraction.The crystal belongs to the triclinic system,space group P1 with a=10.2320(2),b=11.5249(3),c=18.0916(3),α=98.95(1),β =103.601(1),γ=91.272(2)°,V=2044.49(7)3,Z=2,Dc=1.453 g/cm3,T=153(2) K,C42H44CuN2O4P2S4,Mr=894.51,λ(MoKα)=0.71073,μ=0.86 mm-1,S=0.999,(△/σ)max=0.002,the final R=0.0243 and wR=0.0704.A total of 9221 unique reflections were collected,of which 8573 with Ⅰ 2σ(Ⅰ) were observed.The Cu(Ⅱ) atom is five-coordinated in a rather distorted trigonal bipyramidal geometry(τ value=0.537).The Cu-S distances range from 2.3491(4) to 2.4829(4) ,and the Cu-N distances are 1.9987(12) and 2.0584(11) ,respectively.An interesting feature of this adduct resides in its two-dimensional(2D) open framework constructing through hydrogen bonding and π-π interactions.     

Quasiclassical trajectory study of the postquenching dynamics of OH A 2Σ+ by H2/D2 on a global potential energy surface

We report full-dimensional, electronically adiabatic potential energy surfaces (PESs) for the ground state (1A(')) and excited state (2A(')) of OH(3). The PESs are permutationally invariant fits to roughly 23,000 electronic energies (MRCI + Q/aVTZ). Classical trajectory calculations of the postquenching dynamics of OH A (2)Σ(+) are carried out on the 1A(') PES for H(2) and D(2), at previously identified conical intersections (CoIs) [B. C. Hoffman and D. R. Yarkony, J. Chem. Phys. 113, 10091 (2000)]. The initial momenta are sampled fully and partially microcanonically, corresponding to "adiabatic" and "diabatic" models of the dynamics, respectively. Branching ratios of reactive to nonreactive channels from separate C(2v), C(∞v), and C(s) symmetries of CoIs are calculated, as are final rovibrational state distributions of OH and H(2) products. The rovibrational distributions of the OH and D(2) products, the D/H-atom translational energy distribution are calculated and compared to experimental ones. Agreement for these observable quantities is good. The branching between reactive and nonreactive quenching is sensitive to the momenta sampling; very good agreement with experiment is obtained using the diabatic sampling but not with the adiabatic sampling. The vibrational state distributions of H(2)O and HOD (although not measured by experiment) are also presented.     

A new tetracyclic triterpenoid from the leaves of Azadirachta indica

A new tetracyclic triterpenoid zeeshanol [25,26,27-trinor-apotirucalla-(apoeupha)-6alpha-, 21-dihydroxy, 7alpha-acetoxy, 1,14,22-tri-en-3, 16-dione] (1) along with a known constituent desfurano-6alpha-hydroxyazadiradione (2) have been isolated from the methanolic extract of the leaves of Azadirachta indica. The structure and the relative configurations of 1 were determined by the spectroscopic method (1H- and 13C-NMR, IR, and MS) and 2D-NMR experiments.     

Studies on the chemical constituents of the fruits of Cordia latifolia

Four new aromatic compounds have been isolated from the fruits of Cordia latifolia (Boreginaceae) bearing a common basic skeleton but differing in the side chain. Their structures were elucidated using spectrometric methods including 1D- (1H and 13C) and 2D-NMR experiments, (1H, 1H-COSY, NOESY, HMQC and HMBC) and chemical transformations.     

Liquid-liquid extraction and recovery of indium using Cyanex 923

The extraction of In(III) from HCl, H₂SO₄, and HNO₃ media using a 0.20 mol l⁻¹ Cyanex 923 solution in toluene is investigated. In(III) is quantitatively extracted over a fairly wide range of HCl molarity while from H₂SO₄ and HNO₃ media the extraction is quantitative at low acid concentration. The extracted metal ion has been recovered by stripping with 1.0 mol l⁻¹ H₂SO₄. The stoichiometry of the In(III): Cyanex 923 complex is observed to be 1:2. The extraction of In(III) is insignificantly changed in diluents namely toluene, n-hexane, kerosene (160-200 °C), cyclohexane, and xylene having more or less the same dielectric constants, whereas, it decreases with increasing polarity of diluents such as cyclohexanone and chloroform. The extractant is stable towards prolonged acid contact and there is a negligible loss in its extraction efficiency even after recycling for 20 times. The extraction behavior of some commonly associated metal ions namely V(IV), Ti(IV), Al(III), Cr(III), Fe(III), Ga(III), Sb(III), Tl(III), Mn(II), Fe(II), Cu(II), Zn(II), Cd(II), Pb(II), and Tl(I) has also been investigated. Based on the partition data the conditions have been identified for attaining some binary separations of In(III). These conditions are extended for the recovery of pure indium from zinc blend, zinc plating mud, and galena. The recovery of the metal ions is around 95% with purity approximately 99%.     

多原子反应体系的高精度拟合势能面

本文介绍了近几年来我们组构建多原子反应体系的高精度拟合势能面的进展。我们基于神经网络(NN)方法,成功构建了多原子气相分子体系和气相分子在金属表面解离的一系列势能面。这些势能面的拟合精度相当高,并且经过了严格的量子动力学测试,能广泛应用到动力学研究中。我们还提出了一种新的置换不变势能面的拟合方法,即基本不变量神经网络方法(FI-NN)。基本不变量的使用极大地减少了神经网络输入层多项式的个数,有效提高了势能面的计算速度。     

Tetracyclic triterpenoids from the leaves of Azadirachta indica and their insecticidal activities

A new tetranortriterpenoid, meliatetraolenone [24,25,26,27-tetranor-apotirucalla-(apoeupha)-6alpha-O-methyl, 7alpha-senecioyl(7-deacetyl)-11alpha,12alpha,21,23-tetrahydroxy-21,23-epoxy-2,14,20(22)-trien-1,16-dione] (1) was isolated from the methanolic extract of fresh leaves of Azadirachta indica along with the known compound odoratone (3) which was hitherto unreported from this source. Their structures have been elucidated by spectral studies including 2D NMR. The insecticidal activities of 1 as well as those of odoratone (3) are reported. 1 and odoratone both showed mortality on fourth instar larvae of mosquitoes (Anopheles stephensi) with LC(50) values of 16 and 154 ppm, respectively.     

Triterpenoidal constituents of the leaves of Carissa carandas

Studies undertaken on the fresh leaves of Carissa carandas have led to the isolation of four pentacyclic triterpenoids (1-4) including one new constituent carissin (1) and two hitherto unreported compounds 2 and 3. The structure of the new triterpenoid has been elucidated as 3beta-hydroxy-27-E-feruloyloxyurs-12-en-28-oic acid. Compelete assignment of the protons of 2 has also been made based on 2D NMR studies.     

Two new triterpenoids and a steroidal glycoside from the aerial parts of Ocimum basilicum

Studies on the chemical constituents of the aerial parts of Ocimum basilicum have led to the isolation of three new compounds, basilol (1), ocimol (2), and basilimoside (3), along with two known constituents betulinic acid and oleanolic acid. The structures of the new constituents have been elucidated through spectral studies including 2D-NMR experiments (HMQC, HMBC, COSY, NOESY, and J-resolved) and chemical transformation, as p-formylphenyl 3beta-hydroxyolean-12-en-28-oate (1), 2-methoxy-4-carbomethoxyphenyl 3beta-hydroxy-lup-20(29)-en-28-oate (2), and (22E)-24xi-ethyl-25-methylcholesta-5,22-diene-3beta-ol-3-O-D-glucopyranoside (3).