Ursethoxy acid,a new triterpene from Lantana camara

A new pentacyclic triterpene, named ursethoxy acid (1) was isolated from the aerial parts of Lantana camara Linn. Its structure has been elucidated as 3,25-epoxy-3alpha-ethoxy-urs-12-en-28-oic acid through extensive 1D- and 2D-NMR (COSY-45, NOESY, J-resolved, HMQC and HMBC) studies.     

Triterpenoidal Secondary Metabolites from Lantana Camara Linn.

Three new pentacyclic triterpenoids, camarin ( 1 ), lantacin ( 2 ), and camarinin ( 3 ) were isolated from the aerial parts of Lantana camara Linn ., together with seven known compounds. The structures of the new constituents were elucidated by chemical transformation, HR‐EI mass spectrometry, and NMR spectroscopy, including 1D (¹H‐ and ¹³C‐NMR) and 2D (¹H,¹H‐COSY, NOESY, ¹H,¹H‐TOCSY, J‐resolved, HMQC, and HMBC) experiments.     

Structural studies of oxalohydroxamic acid by single crystal X-ray diffraction and spectroscopic methods

The structure of oxalohydroxamic acid has been investigated by X-ray and spectroscopic analyses. It has been shown that oxalohydroxamic acid exists in the oxamic form in the solid as well as in solution. The variable-temperature nuclear magnetic resonance (NMR) studies reveal an exchange of OH and NH protons, the exchange being faster at higher temperatures. The kinetic and the thermodynamic parameters such as the rate constant (K), the free energy of activation (G ^DG), and the energy of activation (E _a) for the exchange process have been obtained. The compound crystallizes in the monoclinic space groupP2₁/c witha=5.208,b=3.864,c=11.482 Å,=111.45°, andZ=2. The structure was solved withMultan 80. The refinement by block diagonal least squares and Fourier methods providedR=0.035. There is strong hydrogen bonding between the molecules which form dimer.     

A new natural product and insecticidal amides from seeds of Piper nigrum Linn

Studies on the petroleum ether soluble and insoluble fraction of ethanol extract of dried ground seeds of Piper nigrum resulted in the isolation and structure elucidation of 1 new and 11 known compounds which include 3 hitherto unreported constituents, namely, cinnamylideneacetone, 3,4-methylenedioxyphenylpropiophenone and 2-hydroxy-4,5-methylenedioxypropiophenone from this plant.     

Morphology-controlled assembly of ZnO nanostructures: a bioinspired method and visible luminescence

In a bioinspired methodology, positively charged polypeptides and polyamines directly catalyse ZnO mineralization under "green" conditions of room temperature and neutral pH. The polyamines not only act as mineralizing agents for the formation of ZnO nanoparticles, but also self-assemble the nanoparticles to form spindle-like morphologies at these very ambient conditions. Both the directional growth of ZnO and its luminescent property have a pH dependency. At higher pH, the ZnO shape changes to a rodlike morphology that exhibits green photoluminescence with different intensity than that for ZnO spindles.     

A comparative study of the reactivity of unsaturated triosmium clusters [Os3(CO)8{μ3-Ph2PCH2P(Ph)C6H4}(μ-H)] and [Os3(CO)9{μ3-η-C7H3(2-Me)NS}(μ-H)] with BuNC

Treatment of unsaturated [Os₃(CO)₈{μ₃-Ph₂PCH₂P(Ph)C₆H₄}(μ-H)] (2) with ^tBuNC at room temperature gives [Os₃(CO)₈(CNBu^t)){μ₃-Ph₂PCH₂P(Ph)C₆H₄}(μ-H)] (3) which on thermolysis in refluxing toluene furnishes [Os₃(CO)₇(CNBu^t){μ₃-Ph₂PCHP(Ph)C₆H₄}(μ-H)₂] (4). Reaction of the labile complex [Os₃(CO)₉(μ-dppm)(NCMe)] (5) with ^tBuNC at room temperature affords the substitution product [Os₃(CO)₉(μ-dppm)(CNBu^t)] (6). Thermolysis of 6 in refluxing toluene gives 4. On the other hand, the reaction of unsaturated [Os₃(CO)₉{μ₃-η²-C₇H₃(2-Me)NS}(μ-H)] (7) with ^tBuNC yields the addition product [Os₃(CO)₉(CNBu^t){μ-η²-C₇H₃(2-Me)NS}(μ-H)] (8) which on decarbonylation in refluxing toluene gives unsaturated [Os₃(CO)₈(CNBu^t){μ₃-η²-C₇H₃(2-Me)NS}(μ-H)] (9). Compound 9 reacts with PPh₃ at room temperature to give the adduct [Os₃(CO)₈(PPh₃)(CNBu^t){μ-η²-C₇H₃(2-Me)NS(μ-H)] (10). Compound 8 exists as two isomers in solution whereas 10 occurs in four isomeric forms. The molecular structures of 3, 6, 8, and 10 have been determined by X-ray diffraction studies.     

Nematicidal natural products from the aerial parts of Lantana camara Linn

Lantanilic acid, camaric acid and oleanolic acid possessing nematicidal activity were isolated from the methanolic extract of the aerial parts of Lantana camara Linn. through bio-assay guided fractionation. These compounds exhibited 98%, 95% and 70% mortality respectively against root-knot nematode Meloidogyne incognita at 0.5% concentration. Conventional nematicide furadan showed 100% mortality at this concentration.     

Insecticidal amides from fruits of Piper nigrum Linn

The petroleum ether and ethyl acetate fractions of dried ground seeds of Piper nigrum Linn. afforded sixteen compounds (1-16) including one new insecticidal amide, pipwaqarine (1) and six constituents (3,4,6,7,11,15) previously unreported from this plant. The structure of (1) has been elucidated through extensive 1D-, 2D-NMR spectral studies as, 1-[13-(3',4'-methylenedioxyphenyl)-2E,4E,12E-tridecatrienoyl]-N-isopentylamide, while those of known constituents through comparison of spectral data. 1 exhibited toxicity of 30ppm against fourth instar larvae of Aedes aegypti Liston determined by WHO method. A portion of petroleum ether fraction was also subjected to GC and GC-MS analysis resulting in the identification of three compounds (17-19) using the NIST Mass spectral search program 1998 and Kovat's retention indices. Two of these compounds, 17 and 18, are reported for the first time from this plant.     

Lauric acid as biological active ligand for complexation with d-block metals

Complexes of lauric acid with general formula M(L)₂ · xH₂O (M = Cu, Co, Ni, Mn) and M(L)₂ (M = Zn, Hg) where L = (CH₃(CH₂)₁₀COOH) have been synthesized. Their elemental analyses show the good agreement between calculated and experimental values. These complexes have been characterized by spectroscopic techniques, such as IR, UV-visible, atomic absorption, and mass spectrometry, which show that the carboxylate group acts as bidentate in the solid state. Kinetic parameters, such as the order of reaction, activation energy, enthalpy, and entropy were calculated using the Coats and Horowitz methods. The calculated values are in a good agreement with the observed TG values that confirm the structural integrity of the complexes. These complexes were screened for their in vitro biological activities against different bacteria and fungi to establish their significance. The article was submitted by the authors in English.