Low-molecular-mass metabolites of fungi. III. Stachybotrolide fromStachybotrys alternans

The new nitrogen-free compound stachybotrolide has been detected among the products of the vital activity ofStachybotrys alternans. The structure of stachybotrolide has been determined on the basis of IR, mass, and¹H and¹³C NMR spectra. To interpret the latter we have made use of DEPT, 2M NMR¹H−¹H chemical shift correlation (¹H−¹H COSY or HMQC) and 2M NMR correlations of¹H−¹³C long-range interactions (HMBC). Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 679–683, September–October, 1998.     

Rhaposerine and rhaserolide, new sesquiterpene lactones fromRhaponticum serratuloides

Two new crystalline guaianolides,viz., rhaposerine and rhaserolide, were isolated from an ethanolic extract of the above-ground part of the plantRhaponticum serratuloides by column chromatography along with sesquiterpene lactones,viz., centaurepensin and acroptilin, which have been found in other plants. The chemical structures of the title lactones were established by¹H and¹³C NMR spectroscopy and 2D¹H−¹H (COSY) and¹³C−¹H (COSY and COLOC) NMR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2010–2014, October, 1999.     

Ajanolide A, a new germacranolide fromAjania fruticulosa

A new germacranolide, ajanolide A, was isolated from aerial parts ofAjania fruticulosa by means of extraction with CHCl₃ and adsorption chromatography. This compound was identified as (1(10)E,3S,4Z,6R,7S,11R)-3-acetoxygermacra-1(10),4-dien-12,6-olide ((1S,7S,10R,13R)-7-acetoxy-4,8,13-trimethyl-11-oxabicyclo[8.3.0]trideca-4(E),8(Z)-dien-12-one) by X-ray diffraction analysis. 2D¹H−¹H (COSY) and¹³C−¹H (COSY) NMR spectroscopy was used for assigning the¹H and¹³C NMR signals in the spectra of ajanolide A. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 167–170, January, 1998.     

Pattern recognition of the multiplet structure of NMR spectra

A new method of analysis of high-resolution NMR spectra was suggested, and an algorithm and the PAREMUS program package for assignment of patterns of the spectral components based on pattern recognition theory were developed. High effectiveness of the method has been exemplified by determination of the values and relative signs of the interring¹H−¹H and¹³C−¹H spin-spin coupling constants in 1,2,3-trichloronaphthalene. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 3, pp. 444–451, March, 1997.     

Dependence of geminal1H−1H and31P−1H spin-spin coupling constants on the specific intramolecular C−H...X interaction

Participation of the proton in a specific intramolecular C−H...X (X=N, 0) interaction leads to an increase in its geminal¹H−¹H and¹H−³¹P spin-spin coupling constants (SSCC). According toab initio calculations carried out in the 6–31G^** basis set, the observed effect is mainly due to the change in the diamagnetic spin-orbital contribution to SSCC. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 306–309, February, 1997.     

13C and19F NMR study of α,β-difluorostyryl derivatives of transition metal carbonylates. A method of signal assignment based on the carbon—fluorine spin-spin coupling constants

The¹³C and¹⁹F NMR spectra ofZ- andE-isomers of β-X-substituted α,β-difluorostyrenes (X=F, Cl, CpFe(CO)₂, Re(CO)₅, Re₂(CO)₉Na) were studied. Direct and long-range (across 1–5 bonds) spin-spin coupling constants and the (¹³C−¹²C) isotope shifts in the¹⁹F NMR spectra were determined. The study of the¹³C satellites in the¹⁹F NMR spectra of substituted difluorostyrenes permitted assignment of the¹³C NMR signals of the vinylic carbon atoms. Similarly, the signals in¹⁹F NMR spectra were assigned based on coupling constants of fluorine withipso-carbon. These assignments were found to be in good agreement with the data available from the literature (X=F, Cl). The developed approach was applied to the elucidation of the structure ofZ−PhCF=CClFe(CO)₂Cp. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya. No. 8, pp. 1575–1579, August, 1998.     

Correlation NMR spectroscopy of 1,1-dichloro-2,3,4,5-tetraphenyl-1-germacyclopenta-2,4-diene

Assignment of all of the signals in the¹H and¹³C NMR spectra of 1,1-dichloro-2,3,4,5-tetraphenyl-l-germacyclopenta-2,4-diene has been carried out using two-dimensional NMR spectroscopy. Translated fromIzvestiya Akademii Nauk Seriya Khimicheskaya, No. 3, pp. 623–625, March, 1997.     

Low-molecular-weight metabolites of fungi. II. Refinement of the structure of stachybotrin

The structure of stachybotrin has been reconsidered in the light of¹H,¹³C,¹H−¹H COSY, HMQC, and HMBC NMR spectra, and the revised structure has been confirmed by x-ray structural analysis. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 666–669, September–October, 1998.     

2-Phenyl-1-boraadamantane complexes. Synthesis and intramolecular dynamics

The reaction of triallylborane with 3-phenylprop-1-yne at 135–140 °C followed by treatment of the reaction mixture with MeOH afforded 7-benzyl-3-methoxy-3-borabicyclo[3.3.1]non-6-ene (1) in 81% yield. Hydroboration of compound1 with a solution of BH₃ in THF yielded the tetrahydrofuran complex of 2-phenyl-1-boraadamantane (2). The reactions of trimethylamine or pyridine with compound2 afforded the trimethylamine (3) or pyridine (4) complexes of 2-phenyl-1-boraadamantane. respectively. Hindered rotation about the C(2)−Ph bond in adduct3 was observed by¹H and¹³C NMR spectroscopy. The activation energy of this process is 58.6 kJ mol⁻¹ (determined by 2D¹H−¹H EXSY spectroscopy).     

NMR studies of the electronic structure of coumarins

¹H and¹³C NMR spectra of a series of coumarin dyes used as active laser media are studied. Electron densities and ring currents are calculated. Formulas for calculating¹³C NMR chemical shifts from quantum mechanical data for aminocoumarins are suggested. NMR data and electronic structure calculations are used to explain the generation properties of coumarins. Translated fromZhurnal Strukturnoi Khimii, Vol. 38, No. 3, pp. 495–502, May–June, 1997.     

13C and1H NMR spectra of substituted dihydropyrroles prepared by the reaction of 2-aminooxazoles and maleimide

Substituted dihydropyrroles were characterized by¹³C and¹H NMR spectra. The spectral patterns of these compounds and reversible hydrogen—deuterium exchange are discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 697–700, April, 2000.     

Withasteroids of Physalis. IX. Physangulide — The first natural 22S-withasteroid

A new withasteroid — physangulide — has been isolated from the leaves ofPhysalis angulata L. It has been shown that physangulide is the first natural 22S-withanolide. Its structure has been determined as 3β,4β,20,24,25-pentahydroxy-1-oxo-5β,6β-epoxy-20R,22S,24S,25R-withanolide. Its¹H and¹³C NMR spectra, confirming this interpretation, are given. Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 366–371, May–June, 1990.     

The chemistry of naphthazarine derivatives

Based on IR and¹H and¹³C NMR spectroscopic studies, the oxidation product of echinochrome with Ag₂O was assigned the structure of 2,3-epoxy-7-ethyl-2,3-dihydro-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone. For part 4, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1607–1609, August, 1999.     

μ-Acyl Os3 clusters containing metallocenyl substituents and products of their protonation

Previously unknown μ-acyl osmium clusters containing simultaneously permethyl-metallocenyl and Os₃ cluster fragments were synthesized. The IR, UV, NMR (¹H and¹³C), and FAB-MS spectra were examined. Protonation of the clusters proceeds at the metal atom of the metallocenyl fragment. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 180–183, January, 1999.     

Triterpene glycosides fromHedera canariensis VI. Structure of L-G1 and L-G1b glycosides from leaves of canary ivy

Two new minor triterpene glycosides L-G₁, and L-G_2b, the 3-O-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl-(1→4)-O-β-D-gentiobiosyl and 3-O-α-L-rhamnopyranosyl-(1→2)-O-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl-(1→4)-O-(6-O-acetyl-β-D-glucopyranosyl)-(1→6)-O-β-D glucopyranosyl esters of 30-norhederagenin, respectively, are isolated from the leaves of canary ivy (Hedera canariensis Willd.). The structures of the glycosides are found by chemical methods and¹H and¹³C NMR spectroscopy. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 623–626, September–October, 1999.     

13C NMR study of 2,3,4,5-tetraphenylsilole dilithium salt

The complete assignment of the signals in the¹³C NMR spectra of 2,3,4,5-tetraphenyl-1-R¹,R²-1-silacyclopenta-2,4-dienes (R¹=R²=H, Me) and of the dianion of lithium salt [(PhC)₄Si]²⁻·2Li⁺ was carried out by 2D NMR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 216–218, January, 1999.     

Low-molecular-mass metabolites of fungi I. Stachybotrin fromStachybotrys alternans

Stachybotrys alternans produces a series of low-molecular-mass compounds. By their column chromatography we have isolated the nitrogen-containing compound stachybotrin. The structure of stachybotrin has been determined on the basis of chemical transformations together with the results of¹H and¹³C NMR spectroscopy, 2M NMR¹H–¹H and¹H–¹³C chemical shift correlation (COSY), correlation of long-range¹H–¹³C interactions (HMBC), measurements of NOEs in a rotating coordinate system (ROESY), and IR and electronimpact mass spectra.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 40 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 599–607, July–August, 1997.     

Reactions of chiral phosphoramidites with complexes Pd(COD)Cl2 and Pt(COD)Cl2

Reactions of phosphoramidites based on (−)-ephedrine and [(1S)-endo]-(−)-borneol with the complexes M(COD)Cl₂ (M is Pd or Pt, and COD is cycloocta-1,5-diene) were studied. The formation ofcis andtrans complexes of the general formulas MCl₂L₂ and M₂Cl₂(μ-Cl)₂L₂ was observed. The structures of the resulting compounds were established by³¹P,¹³C, and¹⁹⁵Pt NMR and IR spectroscopy and by plasma desorption mass spectrometry. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1627–1630, August, 1998.     

Interaction of rhenium hydride (η5-C5Me5)ReH(CO)(NO) with fluorinated alcoholswith fluorinated alcohols

The interaction between the fluorinated alcohols R^FOH (R^F=(CF₃)₂CH and (CF₃)₃C) and rhenium hydride (η⁵-C₅Me₅)ReH(CO)(NO) in hexane and liquid freon was studied in a wide temperature range by IR and¹H NMR methods, respectively. The formation of hydrogen-bonded complexes of two types, ReH...HOR^F and NO...HOR^F, was established. The hydride signal in the¹H NMR spectra at 96 K splits into two signals (at δ=−7.54 and −8.87) corresponding to the free ReH and the ReH...HO complex, respectively. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1405–1407, July, 1997.     

Liquid-crystalline CuII and PdII complexes with nonmesogenic ferrocene-containing β-aminovinyl ketone

New liquid-crystalline heteropolynuclear complexes L₂M (M=Cu²⁺ (2a), Pd²⁺ (2b)) were synthesized by the reactions of C₅H₅FeC₅H₄−C₆H₄NH−C₂H₂−(CO)−C₆H₄OC₁₂H₂₅ (1, LH) with copper(ii) and palladium(ii) acetates. Compound2b was found to possess monotropic nematic and smectic phases;2a exhibits the monotropic nematic phase and a phenomenon of “double melting”. The compositions and structures of compounds1 and2a,b were established by elemental analysis,¹H and¹³C NMR, ESR, and IR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 381–383, February, 1999.