20-Hydroxyecdysone from Stemmacantha uniflora Subsp. satzyperovii

The dynamics of 20-hydroxyecdysone content in vegetative and generative organs of Stemmacantha uniflora subsp. satzyperovii (Soskov) Dittrich, which is distributed over Primorskii Krai, were investigated. A high content of 20-hydroxyecdysone during the plant vegetative period is characteristic of growing organs. The amount is maximal for young leaves during development of racemes (7.8 g/mg) and for ripe achenes (11.15 g/mg).     

Phytoecdysteroids from <Emphasis Type="Italic">Serratula komarovii</Emphasis>

Integristerone A and 2-deoxy-20-hydroxyecdysone were observed for the first time in the aerial and subterrean organs of the eastern Asian plant Serratula komarovii Iljin. -Ecdysone was not found in the plants. The dynamics of phytoecdysteroid content (integristerone A, 20-hydroxyecdysone, and 2-deoxy-20- hydroxyecdysone) in the vegetative and generative organs of this species were investigated.Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 404–406, September–October, 2004.     

Synthesis of 20-hydroxyecdysone 6-chloronicotinates

New esters 2-5 that contain 6-chloropyridine groups characteristic of the alkaloid epibatidine were prepared by acylation of 20-hydroxyecdysone (1) by 6-chloronicotinoylchloride. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 328–331, May–June, 2009.     

A new phytoecdysteroid

A new phytoecdysteroid,viz, 2-deoxy-3-epi-4β, 20-dihydroxycedysone ((20R,22R)-3α,4β 14α,20,22,25-hexahydroxy-5β-cholest-7-en-6-one), named coronatasteronc, was isolated fromSerratula coronata and identified by NMR spectroscopy. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1954–1955, November, 2000.     

Possibilities of multinuclear NMR in the chemistry of heteroorganic compounds

Results of multinuclear NMR studies of some heteroorganic compounds have been presented.According to a report at the conference «Current problems of organometallic chemistry» (May 8–13,1994, Moscow).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 614–616, April, 1994.     

Determination of 20-hydroxyecdysone content by thin-layer chromatography and micellar electrokinetic chromatography

Summary Seasonal dependence of 20-hydroxyecdysone content ofSerratula tinctoria andSerratula wolffii (Asteraceae) was investigated by micellar electrokinetic chromatography (MEKC). Samples were collected each month through the vegetation period. The leaves were dried, milled and extracted with methanol. Clean-up of the extracts was by solid-phase extraction using a polyamide micro-column to remove flavonoids and other plant phenolics which can interfere with the analysis. This work deals with the separation of 20-hydroxyecdysone from polypodine B and the seasonal variation of 20-hydroxyecdysone concentration. Determinations have been performed by both thin-layer chromatography and capillary electrophoresis using micellar electrokinetic chromatography. Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997.     

R'Hg- and Ph3PAu-Derivatives of substituted malononitriles RCH(CN)2

The organomercurials RC(HgR')(CN)₂ (R = Me, Ph; R¹ = Ph, CH₂Ph) have been obtained by the action of organomercury hydroxides R'HgOH or acetates R'HgOAc on substituted malonodinitriles RCH(CN)₂- (Ph₃PAu₃O+BF₄ reacts with the same nitriles to give organogold derivatives RC(AuPPh₃)(CN)₂. The study of the structures of organomercury and -gold compounds by¹H,³¹P and¹⁹⁹Hg NMR spectra as well as by IR spectra show that these compounds exist mainly in the C-form. The degenerated exchange reaction involving the cleavage of C-Hg bond takes place in the phenylmercury derivative of methylmalonodinitrile. Organomercury derivatives of substituted malonodinitriles are stable with respect to symmetrization in solution, in contrast to PhCH(HgPh)CN studied previously.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 129–133, January, 1994.     

Zur Kenntnis organischerLewis-Säuren, 36.Cis—trans-Gleichgewichte und Konformationen von 2,(x)-Dialkyl-1-dicyanomethylencyclohexanen. Wahlweise einfache Darstellung dercis- odertrans-Formen

Knoevenagel condensation of malononitrile withcis- andtrans-2,5-dimethylcyclohexanone (1 c and1 t, respectively) leads to2 c and2 t, respectively, and withtrans-1-decalone to4 t. The equilibria2 c2 t and4 c4 t have been determined as well as, by means of 270-MHz-¹H-NMR, the conformations of these four compounds. The dicyanomethylene group is found to induce axial positions of neighbouring alkyl residues on the cyclohexane ring (or when this is impossible, as in the case of4 t, the twist form of the cyclohexane ring). This results in a strong predominance of thecis isomers in the equilibria2 c2 t and4 c4 t whereas thetrans isomers strongly predominate in the equilibria among the starting ketones. This situation allows the optional preparation of2 c or2 t, and of4 c or4 t, from the more stable starting ketone (or ketone mixture). The free conformational energy of the distorted twist form of4 t amounts to 17 kJ/mol.

Herrn Prof. Dr.E. Ziegler, Graz, zum 70. Geburtstag in aufrichtiger Verbundenheit gewidmet.     

High performance liquid chromatography coupled to nuclear magnetic resonance spectroscopy and mass spectrometry applied to plant products: Identification of ecdysteroids fromSilene otites

Summary HPLC coupled in parallel to nuclear magnetic resonance (NMR) and mass spectrometry (MS) has been used to obtain¹H NMR and mass spectra of a number of ecdysteroids present in an extract of the plantSilene otites. Reversed phase gradient chromatography was performed using a D₂0-acetonitrile-based solvent system. NMR and mass spectra were obtained for integristerone A, 20-hydroxyecdysone, 2-deoxy-20-hydroxyecdysone and 2-deoxyecdysone to provide structural confirmation using continuous and stopped flow HPLC-NMR. The combined HPLC-NMR-MS system described here provided a more comprehensive analysis of the ecdysteroids present in the extract than HPLC-NMR alone.     

Chemie polyfunktioneller Moleküle, 94 Chrom- und Wolfram-pentacarbonylderivate des 4-Methyl-1,2,6-triphosphatricyclo[2.2.1.02,6]heptans (P3-Nortricyclans)

The P₃-nortricyclane 4-methyl-1,2,6-triphosphatricyclo[2.2.1.0^2,6]heptane, CH₃C(CH₂P)₃, (1), is synthesized in a better yield than earlier described from P₄, a Na/K alloy, and CH₃C(CH₂Br)₃ in boiling 1,2-dimethoxyethane. It reacts withM(CO)₅ thf (M=Cr, W) in the molar ratios of 1:1, 1:2, and 1:3 to form the pentacarbonylmetal complexes CH₃C(CH₂P)₃[M(CO)₅] _n [n=1, 2, 3;M=Cr (a), W (b)], (2 a, b–4 a, b).1 gives with Mo(CO)₅ thf only mixtures of CH₃C(CH₂P)₃[Mo(CO)₅] _n andcis-Mo(CO)₄ derivatives, which were identified by their infrared active A₁ v(CO) modes at 2075 and 2025 cm^–1.All the new compounds have been characterized also by their¹H{³¹P},³¹P{¹H} NMR, IR,Raman, and mass spectra.

     

Synthesis ofN-substituted 4-benzoyl-2-iminothiazolium bromides

Substituted thioureas react with 1-bromo-2-benzoylacetylene in various solvents at 20°C to give the correspondingN-substituted 4-benzoyl-2-(R-imino)-3-R′-thiazolium bromides. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 199–200, January, 1997.     

Stereoselective synthesis and moulting activity of 2,3-diepi-20-hydroxyecdysone and 2,3-diepi-5α-20-hydroxyecdysone

The ecdysteroid analogues 2,3-diepi-20-hydroxyecdysone and 2,3-diepi-5α-20-hydroxyecdysone have been synthesized from the readily available ecdysteroid, 20-hydroxyecdysone, and moulting activity has been determined using the Musca bioassay. As expected, the 2,3-diepi-analogue was less active than the parent ecdysteroid, 20-hydroxyecdysone. However, the 2,3-diepi-5α-analogue, which was expected to be inactive in the assay, exhibited moulting activity though it was approximately 1.5-fold less active than its 5β-analogue. The activity of the 5α-analogue could possibly result from the ability of this compound to bind to the ecdysteroid receptor. Alternatively, a possible in vivo C-5 epimerization of the 2,3-diepi-5α-analogue to the corresponding 5β-analogue could account for its activity.     

Reactivity of Aquadiethylenetriamineplatinum(II) Ion with Disulfide Moiety Cystine: A Kinetic and Mechanistic Approach

Abstract

Substitution reactions of the complex [Pt(dien)H₂O]²⁺ (where dien = diethylentriamine or 1,5-diamino-3-azapentane) with sulfur-containing L-cystine have been studied in a 1.0 × 10^?1 mol dm^?3 aqueous perchlorate medium at various temperatures (298–323 K) and 4.45 ≤ pH ≤ 2.15 using UV-vis spectroscopy. The products obtained have been characterized by their infrared and ¹H NMR datasets at various pH levels and temperatures. From infrared and ¹H NMR data, products have indicated that [Pt(dien)H₂O]²⁺ reacted with L-cystine forming a Pt–S bond at low pH. At high pH, a product complex through the Pt–N bond has been formed. All rate constants have been evaluated from nonlinear double exponential plots. The activation parameters ΔH^# and ΔS^# have been determined using the Eyring equation. The products, S_Ni, and reversible rate constants have been evaluated.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT      

Synthesis and Stereochemistry of New N-Substituted Cytisine Derivatives

A series of new N-substituted cytisine derivatives was synthesized. The ¹ H and ¹³ C NMR spectra of certain compounds exhibit a doubled set of signals. This is explained by formation of diastereomeric pairs in compounds containing an asymmetric center in the substituents. The signal splitting in -COHC=CHCO ₂ H and HC=O (formyl) derivatives is explained by the existence of Z and E invertomers. Their stereochemical features are discussed. Amide conjugation is confirmed by temperature experiments.     

The Chemical Constituents from Fruits of Catalpa bignonioides Walt. and Their α-Glucosidase Inhibitory Activity and Insulin Secretion Effect

Catalpa pod has been used in traditional medicine for the treatment of diabetes mellitus in South America. Studies on the constituents of Catalpa species have shown that it is rich in iridoids. In the present study, three previously undescribed compounds (2–4), including two secoiridoid derivatives along with twelve known compounds, were isolated from the fruits of Catalpa bignonioides Walt. In addition, fully assigned ¹³C-NMR of 5,6-dihydroxy-7,4’-dimethoxyflavone-6-O-sophoroside (1) is reported for the first time in the present study. The structures of compounds were determined on the basis of extensive spectroscopic methods, including UV, IR, 1D, and 2D NMR, mass spectroscopy, and CD spectroscopic data. All the isolated compounds were evaluated for α-glucosidase inhibitory activity. Among the tested compounds, compounds 2, 3, and 9 exhibited significant inhibitory activity against α-glucosidase enzyme assay. Meanwhile, the effect of compounds 2, 3, and 9 on glucose-stimulated insulin secretion (GSIS) was measured using pancreatic β-cells. Compounds 2, 3, and 9 exhibited non-cytotoxicity-stimulated insulin secretion in INS-1 cells. The expression levels of proteins associated with β-cell function and insulin secretion such as phosphorylation of total insulin receptor substrate-2 (IRS-2), phosphatidylinositol 3-kinase (PI3K), Akt, activated pancreatic duodenal homeobox-1 (PDX-1), and peroxisome proliferator-activated receptor-γ (PPAR-γ) were increased in INS-1 cells after treatment with compounds 2, 3, and 9. The findings of the present study could provide a scientific warrant for their application as a potential antidiabetic agent.     

Supramolecular amide and thioamide synthons in hydrogen bonding patterns of N-aryl-furamides and N-aryl-thiofuramides

The supramolecular synthon of amide group in the primary and secondary amides is well recognized to be infinite chains of the C(4) type formed by the intermolecular hydrogen bond of the type N–HO=C. On the other hand, there is a lack of structural data for the thioamides. Three compounds belonging to the class of N-aryl-fura-mides (N-(4-bromophenyl)-5-bromo-2-furancarboxamide, N-(4-chlorophenyl)-5-bromo-2-furancarboxamide) and to the class of N-aryl-thiofuramide (N-(4-methoxyphenyl)-2-furanthiocarboxamide) are prepared and characterized by the NMR spectroscopy in solution; molecular and crystal structures in the solid state have been determined by X-ray single crystal diffractometry and the structures in the gas phase by DFT and AM1 calculations. The investigation is carried out in order to establish supramolecular amide and thioamide synthons of hydrogen bonding patterns in these crystal structures. The geometry of the N–HO=C and the N–HS=C type of hydrogen bonds are compared due to the possibility of the N–H amide group to form intramolecular hydrogen bond with the furan oxygen atom, thus, commonly, leading to the three-center hydrogen bond pattern. The competition between the S=C proton acceptor of thioamides and the other proton acceptors (such as methoxy group) for the amide N–H proton donor group has been investigated. In that context, the above-mentioned compounds are correlated with the others of this class, structurally determined, so far.     

Synthesis and structures of pyridoannelated 1,2,3,4-tetrazine 1,3-dioxides

Treatment of 2- and 4-amino-3-(tert-butyl-NNO-azoxy)pyridines with nitrating agents (N₂O₅or NO₂BF₄) afforded the first representatives of pyridoannelated 1,2,3,4-tetrazine di-N-oxides, viz., pyrido[2,3-e][1,2,3,4]tetrazine 1,3-dioxide (9), 7-nitropyrido[2,3-e][1,2,3,4]tetrazine 1,3-dioxide (10), and pyrido[3,4-e][1,2,3,4]tetrazine 2,4-dioxide (11). These compounds were studied by ¹H, ¹³C, and ¹⁴N NMR spectroscopy. The 1:1 complex of compound 10 with benzene was studied by X-ray diffraction analysis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2471–2477, November, 2004.     

Determination of the structure of 7-diethylamino-4-(1,2,3-triazol-1-yl)-2H-1-benzopyran-2-one derivatives using two-dimensional heteronuclear chemical-shift correlated NMR techniques

¹H and¹³C NMR spectra of 7-diethylamino-4-(1,2,3-triazol-1-yl)-2H-1-benzopyran-2-one derivatives have been studied. The location of the substituent in the 1,2,3-triazole ring was determined by the 2D COLOC method. It was established that the H(3) and H(5) protons in the coumarin moiety experience anisotropic influence of the phenyl subsituent at the C(5) atom in the triazole ring.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1330–1332, July, 1994.     

Thio Analogs of Pyrimidine Bases: Synthesis And Spectroscopic Study of New Potentially Biologically Active Disulfides of N,O-(N,N- or O,O-)-Di- and N,N,O-Tri-(o-, m-, and p-)bromobenzyl-2-thiouracils

Nine new disulfides of N,O-(N,N- or O,O-)-di- and N,N,O-tri-(o-, m- and p-)bromobenzyl-2-thiouracils have been prepared. The structures of these compounds were confirmed by spectroscopic (FT-IR, UV-Vis, ¹H NMR) and elemental analyses. Estimation of pharmacotherapeutic potential has been made for synthesized compounds on the basis of Prediction of Activity Spectra for Substances (PASS).     

Study of homogenous hydrogenation of acetylene compounds withpara-hydrogen and Pd(0) and Pt(0) complexes byin situ NMR spectroscopy

η² -C₆₀Pd(PPh₃)₂, η² -C₆₀Pt(PPh₃)₂ and C₂H₄Pt(PPh₃)₂ have been used as catalysts for homogeneous hydrogenation of acetylene compounds enriched in para-hydrogen (p-H₂). The study of the processes has been carried out byin situ NMR spectroscopy. It has been concluded that the nature of the substrate affects the intensity and patterns of polarization signals.