Chemical examination of embelia ribes—VI Synthesis of some new methylene-bisbenzoquinones

By the condensation of 2,5-dihydroxybenzoquinone (I) with various aldehydes (bis-desundecyl)vilangins and anhydrovilangins (II and III), have been synthesized and their properties recorded.     

Chemical examination of Tylophora asthmatica—V Structure of tylophorinine

Tylophorinine, the minor alkaloid of Tylophora asthmatica, has been oxidized to yield 2,3,6-trimethoxyphenanthrene-9,10-dicarboxylic acid. A synthesis of the corresponding imide has been achieved. Desoxytylophorinine, obtained by hydrogenolysis of the alkaloid, has been synthesized. These results in conjunction with other degradation experiments have enabled the assignment of the structure XIV to tylophorinine.     

Chemical examination of Tylophora asthmatica—IV Synthesis of tylophorine

Structure (I) assigned to tylophorine has been confirmed by a total synthesis.     

Chemical examination of Tylophora asthmatica—II

Tylophorine has been degraded to a compound, identified as 2:3:6:7-tetramethoxy-9-methylphenanthrene. In conjunction with other degradation results and biogenetic considerations, tylophorine is now formulated as 2:3:6:7-tetramethoxyphenanthro(9:10:6′:7′)indolizidine.

A synthesis of the basic ring system, phenanthro-(9:10:6′:7′)indolizidine, present in tylophorine has been achieved.     

The chemical examination of Iris nepalensis—I Structure of irisolone

On the basis of degradation experiments, irisolone, a new isoflavone from Iris nepalensis has been assigned structure I (R = H).     

The extractives of Vitex lucens—I

Vitexin, isolated from Vitex lucens, has been formulated as C₂₁H₂₀O₁₀ and, in agreement with recent workers, structure (I) has been assigned to the compound. β-sitosterol has been isolated from the heartwood.     

The diterpenes of dacrydium colensoi—III

An oxidoditerpene, isolated from the heartwood of Dacrydium colensoi, has been shown to be 18-hydroxy-2-ketomanoyl oxide (V).     

Alkaloids of Glycosmis arborea—III Structure of arborinine

Arborinine is identical with the 2,3-dimethoxy-1-hydroxy-10-methylacridone of Hughes et al.     

Alkaloids of Glycosmis arborea—II Structure of arborine

On the basis of a critical study of the ultra-violet and the infra-red absorption spectra of arborine, dihydroarborine, 1,2-dimethylquinazol-4-one, 2-ethyl-1-methylquinazol-4-one, 2,3-dihydro-1,2-dimethylquinazol-4-one and 2,3-dihydro-2-ethyl-1-methylquinazol-4-one, it has been shown that arborine is 2-benzyl-1-methylquinazol-4-one and not the tautomeric form, 2-benzylidene-1-methylquinazol-4-one. This has been confirmed on the basis of the nuclear magnetic resonance spectrum of arborine. Incidentally, it has been shown that 'glycosine' of Chatterjee and Ghosh Majumdar is not a new alkaloid and this name should be deleted from the literature.     

Synthesis of pyrimidine derivatives using N-bis(methylthio)methylenecyanamide

N-Bis(methylthio)methylenecyanamide ( 1 ) was allowed to react with active methylene compounds (methyl cyanoacetate, dimethyl malonate, ethyl acetoacetate, ethyl phenylacetate) in the presence of potassium carbonate or potassium hydroxide in dimethyl sulfoxide followed by the treatment using appropriate a base or an acid to give the corresponding 6-methylthiouracil derivatives in 15–80% yields. These uracil derivatives are found to be useful intermediates for the synthesis of 6-aminouracils and fused pyrimidine derivatives.     

Synthesis and characterisation of alkyl-N,N′-bis(salicylidene)ethylenediamino- and alkyl-N,N′-bis(salicylidene)-1,2-phenylenediaminogallium or indium complexes: crystal structure of methyl-N,N′-bis(salicylidene)-1,2-phenylenediaminoindium

The reaction of trialkylgallium or indium R₃M (M=In, Ga; R=Me, Et) with N,N′-ethylenebis(salicylideneimine) or 1,2-N,N′-phenylenebis(salicylideneimine) yields seven intramolecularly coordinated organogallium or organoindium complexes. Two hydroxyl protons in the ligands react with both trialkylindium and trimethylgallium, while one hydroxyl group reacts exclusively with triethylgallium. The complexes obtained have been fully characterised by elemental analysis, ¹H-NMR, IR and mass spectroscopy. The structure of methyl-N,N′-bis(salicylidene)-1,2-phenylenediaminoindium (1) has been determined by single-crystal X-ray analysis. The In atom is five coordinate in the structure. Fluorescence spectroscopy has shown that the maximum emission wavelength of 1 is 499 nm upon radiation by UV light.     

Synthesis of some new N,N′-diarylsubstituted methylene-bis-dihydro-2H-1,3-benzoxazines

The synthesis of a new series of six-membered N,N′-diarylsubstituted methylene-bis-dihydro-2H-1,3-benzoxazines （5a-e） was achieved in excellent yields by Mannich-type condensation of N,N′-diarylsubstituted methylene-bis-o-hydroxybenzyl amines （4a- e） with formaldehyde in chloroform at reflux. These amines （4a-e） were obtained by the reduction of N, Nr-diarylsubstituted methylene-bis-o-hydroxybenzyl imines （3a-e） with NaBH4, which inturn were obtained by the condensation of methylene-bissalicylaldehyde （2） with various substituted arylamines.     

Synthesis of N,N′-dimethyl-N,N′-dibutyl malonamide functionalized polymer and its sorption affinities towards U(VI) and Th(IV) ions

A novel chelating polymeric material was synthesized by chemical anchoring of N,N′-dimethyl-N,N′-dibutyl malonamide (DMDBMA) with chloromethylated polystyrene-divinyl benzene polymer. The polymeric material thus prepared was characterized by ¹³C NMR, FT-IR spectroscopy and CHN elemental analysis. The fabricated polymeric material exhibited superior binding for hexa-valent and tetra-valent metal ions such as U(VI) and Th(IV). Various physico-chemical properties of the functionalized polymer like phase adsorption kinetics, metal sorption mechanism and metal sorption capacity was studied in the static method. Adsorption kinetics studies show that <20 min was sufficient for >99.99% adsorption of Th(IV) and U(VI). The kinetics for adsorption of U(VI) and Th(IV) was found to follow the first order Lagergren rate kinetics. Adsorption of U(VI) on the malonamide functionalized polymer followed the Langmuir adsorption isotherm. The Langmuir monolayer adsorption phenomenon was also confirmed by the theoretical approach calculated based on the adsorption kinetics. The metal sorption capacities for uranium and thorium were found to be 18.78 ± 1.53 mg and 15.74 ± 1.59 mg/g of the chelating polymer at 3 M HNO₃, respectively.     

Synthesis, spectroscopic studies and nonlinear optical behavior of N,N′-bis(2-hydroxy-1-naphthylmethylidene)-1-methyl-1,2-diaminoethane-N,N′,O,O′-nickel(II)

A Schiff base complex N,N′-bis(2-hydroxy-1-naphthylmethylidene)-1-methyl-1,2- diaminoethane-N,N′,O,O′-nickel(II) has been synthesized. The title compound has been characterized by FT-IR and UV–vis spectroscopies. The UV–vis experiments indicate that the compound has solvatochromism in the UV region, implying non-zero molecular first hyperpolarizability. To investigate microscopic second-order nonlinear optical (NLO) behavior of the examined complex, the electric dipole moments (μ) and the first static hyperpolarizabilities (β) were computed using Finite Field second-order Møller Plesset (FF MP2) perturbation procedure. According to ab initio quantum mechanical calculations, the title complex exhibits non-zero β values, revealing microscopic second-order NLO behavior.     

VNb9O25−δ—Synthesis, electrical conducting behaviour and density functional theory (DFT) calculation

In order to investigate the influence of the oxygen partial pressure (p(O₂)) on the electrical conductivity, VNb₉O₂₅ was prepared by thermal decomposition of freeze-dried oxalate precursors and by a solid state reaction of V₂O₅/Nb₂O₅ mixtures. The samples were characterised by X-ray diffraction, grain size analysis and scanning electron microscopy (SEM). The electrical conductivity of the n-type semiconductor VNb₉O_25−δ can be interpreted as an activated hopping process with a preferred localisation of charge carriers at V(IV) centres. The electronic structure of VNb₉O_25−δ was calculated within the framework of the local density approximation (LDA) to DFT. Partial reduction of V(V) centres causes localised vanadium states to appear inside the band gap. The calculated activation energy values are in good agreement with the experimental ones.     

Terpenoids—LVII Synthesis of some germacrane derivatives

Both liquid and solid hexahydrocostunolides obtained by the pressure hydrogenation of costunolide (V) and solid dihydrocostunolide (VI) respectively, give the same optically active hexahydrogermacol (IIIa), when subjected to controlled reduction with LiAlH₄, followed by Huang-Minlon reduction. The alcohol (IIIa) on oxidation with chromic oxide gives optically active hexahydrogermacrone (IIa). Dehydration of IIIa with KHSO₄ followed by catalytic hydrogenation gives the optically inactive saturated hydrocarbon, germacrane (IV). Since the total synthesis of solid dihydrocostunolide (VI) has already been achieved the preparation of IIIa, IIa and IV from VI constitutes a total synthesis of the above three compounds.     

O-炔丙基-N,N-二(2-氯乙基)-4-氨基苯酚的合成

以对氨基苯酚（1）为原料,经氨基的羟乙基化、酚羟基的苄基保护、氯代、脱保护制得N,N-二 (2-氯乙基) -对氨基苯酚（5）;在碳酸铯作用下,5与溴丙炔经O-烷基化反应合成了新化合物--O-炔丙基-N, N-二(2-氯乙基)-4-氨基苯酚,其结构经¹H NMR, ¹³C NMR和MS表征。     

Chemical examination of Andrographis echioides—II Structure and synthesis of echioidin

On the basis of degradative and spectral evidence and synthesis, echioidin, the new flavone glucoside isolated from Andrographis echioides Nees, is shown to be 5-hydroxy-2′-β- -glucosidoxy-7-methoxyflavone (echioidinin-2′-β- -glucoside).