Secondary-ion mass spectrometry of some catalpol and mussaenoside derivatives

The iridoid glycosides catalpol, veronicoside, catalposide, mussaenoside, and 8-epiloganin have been investigated by secondary-ion mass spectrometry (SIMS). A tendency of these compounds to give cationized1 form of the molecular ions in the SIMS regime has been shown. In the SIMS spectra of veronicoside and catalposide the maximum peaks were those of acyl cations, and in the cases of mussaenoside and 8-epilonganin they were the peaks of ions formed by the elimination of a glucose molecule.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 62–65, January–February, 1996. Original article submitted Spetemebr 17, 1995.     

Synthesis and mechanism of the formation of bis(methylamides) of pyrazoledicarboxylic acids

The reaction of ethoxymethyleneoxaloacetic ester with phenylhydrazine and methylhydrazine has been studied. It has been established that the addition of phenylhydrazine takes place to the ethoxy group through the -nitrogen atom, and the addition of methylhydrazine to the ethoxy group predominantly through the -nitrogen atom. Several derivatives of -alkyl(aryl)hydrazinomethyleneoxaloacetic esters have been obtained. A series of bis(methylamides) and several diamides of 1-alkyl(aryl)pyrazoledicarboxylic acids have been synthesized. Their structure has been determined on the basis of their UV spectra and their breakdown by hydrolysis to known acids. It has been found that in the alkylation of an ester of 3,4-pyrazoledicarboxylic acid with alkyl halides followed by amidation, two isomeric bis(methylamide)s are formed, apparently with the predominance of derivatives of 1-alkyl-3, 4-pyrazoledicarboxylic acids. It has been established that the bis(methylamide)s of 1-alkyl-3,4-pyrazoledicarboxylic and of 1-alkyl-4, 5-pyrazoledicarboxylic acids have characteristic UV spectra differing from one another. The bis(methylamide)s obtained are pharmacologically active substances.     

Spectroscopic,thermal and antimicrobial properties of the copper(II) complex of Schiff base derived from 2‐(salicylidene) aminopyridine

Schiff bases and their complex combinations with metallic ions represent a class of compounds with antimicrobial activity. A ligand was prepared by condensation of the salicylaldehyde with 2‐aminopyridine obtaining 2‐(salicylidene) aminopyridine (SB) with a high capacity for complexing Cu(II) ions. The new compound has been characterized by physical constants (melting point, solubility, stability) and the chemical structure was confirmed by elemental, spectral (IR, UV–visible, ¹H NMR and ¹³C‐NMR) and thermal analyses. The elemental analysis gives a coordination ratio of 1:2 metal:Schiff base. Lethal dose 50 (DL₅₀) values of new Schiff base and their complex with metallic ions were established. The antimicrobial activity of this complex was tested in comparison with the activity of the corresponding Schiff base on strains of Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Escherichia coli, Candida albicans, and Klebsiella. These were compared with the activity of the reference drugs (chloramphenicol, tetracycline, ofloxacin and nystatin) on the above‐mentioned strains. It has been established that all compounds tested were very active against both Gram‐positive and Gram‐negative bacteria. Copyright © 2012 John Wiley & Sons, Ltd.     

Linear dependence of the degree of aggregation on the solvent aggregating power (SAgP)

With k₈/k₁₆, the ratio of the hydrolytic rate-constants of p-nitrophenyl octanoate (C8) to hexadecanoate (C16) , as the indicator of the degree of aggregation, the linear dependence of the degree of aggregation on solvent aggregating power (SAgP) has been established in five aquiorgano solvents, each within a certain range of volume fraction (? values) of the organic cosolvent. The meaning of this linearity has been discussed.     

Nickel(II), copper(II) and zinc(II) complexes withN-phenylglycine in water-methanol solution

The complex equilibria of the Ni(II), Cu(II), and Zn(II) complexes withN-phenylglycine have been studied by computer analysis of potentiometric data. The mode of coordination has been established by¹H NMR and IR studies.

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Nickel(II), Kupfer(II) und Zink(II)-Komplexe mitN-Phenylglycin in Wasser-Methanol-Lösung

Zusammenfassung Anhand der Computer-Analyse von potentiometrischen Daten wurden die Bildungsgleichgewichte von Nickel(II), Kupfer(II) und Zinc(II)-Komplexen mitN-Phenylglycin untersucht. Zur Bestätigung des Koordinationstyps wurden¹H-NMR- und IR-Messungen vorgenommen.

     

Tris-[3-hydroxy-1,2-dimethyl-pyridin-4(1H)-onato]cobalt(III)

The preparation and properties of tris-[3-hydroxy-1,2-dimethyl-pyridin-4(1H)-onato]cobalt(III) are described. The structure of the fac isomer has been established by X-ray diffraction techniques. Solvation characteristics of this complex have been assessed through solubility measurements in methanol–water mixtures. The complex is very inert in neutral solution but undergoes acid-catalysed aquation at lower pHs.     

Synergic effect of triphenylphosphine oxide (TPPO) on the extraction of Hg(II), Se(IV), Co(II) and Mn(II) with fluorinated pyrazolone (HPMTFP)

Extraction of Hg(II), Se(IV), Mn(II) and Co(II) has been carried out with 1-phenyl-3-methyl-4-trifluoroacetyl-2-pyrazolin-5-one (HPMTFP) and triphenylphosphine oxide (TPPO) into chloroform from pH 1–10. Quantitative extraction of Hg(II), Mn(II) and Co(II) at pH 4 with equimolar 0.05M (PMTFP+TPPO) in chloroform was observed. Se(IV) remains unextracted at this pH range. The stoichiometric composition of the extracted complexes M(PMTFP)₂·nH₂O (M=Mn, Hg), M(PMTFP)₂·2TPPO (M=Mn and Co) and Co(PMTFP)₂·TPPO·H₂O at less than 0.1M TPPO has been established. The formation constantsK _m,0 andK _m,n and stability constants _m,n have been computed. The analytical method developed was applied to the IAEA standard reference material (SRM) potato fluor V-4 for the determination of these elements using NAA technique.     

Biocatalytic Approach for the Total Synthesis of (–)‐Malyngolide and Its C(5)‐Epimer

An enzymatic approach has been successfully utilized in the total synthesis of (–)‐malyngolide and its C(5)‐epimer. The required configuration was established by an enzymatic kinetic resolution and Sharpless asymmetric dihydroxylation.     

Synthesis and study of block copolycondensates containing polysiloxane and unsaturated polyester blocks in the chain. II. Poly(unsaturated esters-b-siloxanes) with blocks linked by Si?C bonds and poly(butadienes-b-siloxanes)

Poly(unsaturated esters-b-siloxanes) whose blocks are linked by Si? C bonds and poly(butadienes-b-siloxanes) have been obtained by polycondensation of ω,ω′-diepoxy polydimethylsiloxanes and ω,ω′-dicarboxylic poly(unsaturated esters). The reaction between polysiloxanes with Si? H end groups and allylepoxy has been studied; the resulting ω,ω-diepoxy polysiloxanes have the expected structure. The polycondensation of oligomers with, respectively, epoxy and carboxylic end groups has been studied and the optimal conditions established. The samples with Si? C bonds are not affected by hydrolysis in pure water. The poly(siloxanes-b-unsaturated esters) can be cured by UV light.     

Bioactive versatile azomethine complexes of organotin(IV) and organosilicon(IV)

Diorganotin(IV) and diorganosilicon(IV) derivatives of the types R₂MCl(TSCZ) and R₂M(TSCZ)₂ (where TSCZ is the anion of a thiosemicarbazone ligand, R=Ph or Me and M=Sn or Si) have been synthesized and characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding has been established on the basis of IR and ¹H, ¹³C ²⁹Si and ¹¹⁹Sn NMR spectroscopic studies. Some of the representative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria in vivoas well as in vitro.The results of these investigations are reported. © 1998 John Wiley & Sons, Ltd.     

Verproside,a New Iridoid Glucoside from Veronica officinalis L. (Scrophulariaceae)

A new iridoid glucoside, verproside (2) , has been isolated from Veronica officinalis L. and its structure has been established to be 6-O-protocatechuoylcatalpol.     

Preparation and characterization of Co(II), Ni(II) and Cu(II) complexes of a ligand containing 1,3,4-thiadiazole groups

(1R,2R)-1,2-bis-(5-amino-1,3,4-thiadiazole-2-yl)ethane-1,2-diol (L) has been prepared by the reaction of thiosemicarbazide with (2R,3R)-(+)-tartaric acid (I) and phosphorous oxychloride, and its complexes with Co(II), Ni(II) and Cu(II) have been obtained. The structures of the ligand and its complexes have been established by i. r., ¹H- and ¹³C-n.m.r. spectra, u.v.–vis–nir spectroscopy, elemental analyses, T.g.-D.t.a. and magnetic susceptibility measurements.     

Total synthesis of (S)-(+)-ent-phomapyrones B and surugapyrone B

Phomapyrone B ( 1 ), the 2-pyrones isolated from the phytopathogenic fungus Leptosphaeria maculans, has been synthesized as the enantiomeric form starting from (S)-2-methylbutanol ( 4 ). Surugapyrone B ( 3 ) isolated from Streptmyces sp. USF-6280 as an antioxidant has also been synthesized as a natural form. The absolute configuration of phomapyrone B ( 1 ) was estimated to be the (R)-form and that of surugapyrone B ( 3 ) being the (S)-form. A series of 2-pyrone derivatives 17 have been synthesized through the established procedure and their DPPH radical-scavenging activities have also been evaluated.     

Synthesis and Crystal Structure of (Z)-Ethyl 5-(phenylamino)-3-(phenylimino)-3H-1,2-dithiole-4-carboxylate

The compound (Z)-ethyl 5-(phenylamino)-3-(phenylimino)-3H-1,2-dithiole-4-carboxylate 3 has been synthesized by the reaction of ethylacetoacetate 1 and phenylisothiocyanate 2. Its structure has been established by ¹H NMR, ¹³C NMR, infrared, mass spectra, and x-ray crystallography.      

Synthesis and structure of [(DMSO)2H][OsNO(DMSO)Cl4]

A new complex of dimethyl sulfoxide nitrosoosmium [(DMSO)₂H][OsNO(DMSO)Cl₄] has been prepared by reacting H₂[OsNOCl₅] with DMSO in acetone. Its structure has been established by IR spectroscopy and X-ray structural analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1333–1334, July, 1994.     

Studies on the Alkaloid of Formosan Lauraceous Plants XX Alkaloids of Lindera Oldhamii Hemsl. (3)

The structure of lindoldhamine (1), isolated from the leaves of Lindera oldhamii Hemsl., has been established as 1, by spectral data and chemical degradations.     

Structure of the Z,Z-Germacranolide 1(10)Z,4Z-Hanphyllin

The spatial structure of 1(10)Z, 4Z-hanphyllin has been established by the x-ray method. A new conformation of the ten-membered ring in Z, Z-germacranolides has been found - the₁₅ D ₅,₁ D ₁₄ boat-boat type. The probabilities of the realization of the conformers of this compound and of its C3-epimer have been calculated by the method of molecular mechanics.Institute of Organic Synthesis and Coal Chemistry, National Academy of Sciences of the Republic of Kazakhstan, 470061, Karaganda, ul. 40 let Khazakhstana, 1. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 50–53, January February, 1996. Original article submitted August 14, 1995.     

Structure of 3-(2-aminothiazol-4-yl)coumarin

The structure of 3-(2-aminothiazol-4-yl)coumarin has been established by X-ray structural analysis. The data obtained were compared with the results of molecular mechanics calculations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 492–494, March, 1995.     

Synthesis and characterization of rhodium(III), iridium(III), ruthenium(III) and osmium(III) complexes containing sterically hindered heterocyclic ligands

Summary Some thiazolidine-2-thione and thiomorpholin-3-one complexes of rhodium(lll), iridium(III), ruthenium(III) and osmium(III) have been prepared and characterized by chemical analysis, conductivity measurements, room temperature magnetic moment studies, electronic, i.r. and far i.r. spectra and n.m.r. measurements. From the magnetic properties it was concluded that the above ligands form low-spin complexes with all the metal ions. The position and multiplicity of the metal-halogen stretching modes in the far-i.r. region have been extensively investigated and discussed; the results are particularly useful in distinguishing between themer- andfac-isomers in the octahedral compounds of the ML₃ X₃ type. The wavelengths of the principal electronic absorption peaks have been accounted for quantitatively in terms of the crystal field theory and the various parameters have been calculated. On the basis of the electronic spectra a trigonal bipyramidal geometry,D _3h, has been established for the Ru(tm)₂Cl₃ complex; the Ir(rm)₂Cl₃ · H₂O complex has also been prepared. It is penta-coordinated and a trigonal bipyramidal environment is suggested for the iridium(III) ion.     

Conformationnal equilibrium of glucides on the level of liaisons sp 2 -sp 3 C-C. IV. Hybrid furans sp 2 in C(3)

The conformation of 34 branched-chain unsaturated sugars, prepared by reacting different Wittig reagents with a series of 1,2-O-isopropylidene-furannosul-3-oses, has been studied by PMR spectroscopy. The position of each compound in the flexible conformational cycle has been established by using the known stereo-dependence of the allylic coupling constants and checked with the other parameters of the spectra. An ‘isopropylidenic’ ⁴J_2,4 coupling constant, present in all compounds whose H—C(4) is endo and absent in their C(4)-epimers has proved useful for configurational assignment at C(4).