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.     

Triterpene glycosides ofAstragalus and their genins LVII. The structure of cyclopycnanthogenin

A new cycloartane methysteroid cyclopycnanthogenin, has been found in stems of the plantAstragalus pycnanthus Boriss. (Leguminosae). Its structure has been determined on the basis of IR, mass, and¹H and¹³C NMR spectra with the involvement of DEPT experiments and 2M¹H−¹H and¹H−¹³C chemical shift correlations [¹H−¹H COSY and¹H−¹³C (HMQC)] and also 2M NMR correlations of long-range¹H−¹³C interactions (HMBC). Cyclopycnanthogenin is 6α, 16β, 25-trihydroxy-20R, 24S-epoxycycloartane-3-one. 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. 515–518, July–August, 1998.     

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.     

Triterpenoids fromAbies species 18. NMR spectra of abieslactone and its dehydro derivative

The contradictions in the interpretations of the¹³C NMR spectrum of a natural lanostanoid, abieslactone, and of the 1H NMR spectrum a its 9,11-dehydro derivative reported in the literature were resolved by two-dimensional¹H-¹H and¹³C-¹H (COSY) NMR spectroscopy.Translated fromIzvestiya Akademi Nauk. Seriya Khimicheskaya, No. 11, pp.2780–2784, November,1996     

New Sesquiterpene Glycosides from Culture Hairy Roots of Catharanthus roseus

Two new compounds cadin-2-en-1β-ol-1β-D-glucuronopyranoside （1）, guaia-l,7-dien-3β,13-diol-13α-D- glucofuranoside （2） along with three known compounds have been isolated from the culture hairy roots of Catharanthus roseus. Their structures have been elucidated with the help of 500 MHz NMR using 1D and 2D spectral methods： viz： ^1H and ^13C NMR, ^1H-^1H COSY, ^1H-^13C HETCOR and DEPT aided by ELMS, FAB-MS, HR-FABMS and IR spectroscopy.     

Triterpenoids fromAbies species

Two new lanostane lactones were isolated from a neutral part of an ethereal extract of dried needle-free shoots of Siberian fir. Their structures were proposed based on comparison of their¹³C and¹H NMR spectra with the spectra of known triterpenoid lactones with similar structures. For Part 22, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2064–2066, October, 1998.     

New catharanthusopimaranoside A and B from hairy root cultures of Catharanthus roseus

Two new compounds catharanthusopimaranoside A (1) and catharanthusopimaranoside B (2) along with three known compounds have been isolated from the hairy root cultures of Catharanthus roseus. Their structures have been elucidated with the help of 500 MHz NMR using 1D and 2D spectral methods viz: NMR, ¹H-¹H COSY, ¹H-¹³C HETCOR, etc., and DEPT aided by EIMS, FABMS, and IR spectroscopy. __________ Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 369–372, July–August, 2008.     

Production,Characterization, and Properties of Sophorolipids from the Yeast <Emphasis Type="Italic">Candida bombicola</Emphasis> using a Low-cost Fermentative Medium

The yeast Candida bombicola produces biosurfactant with properties akin to those of sophorolipid (SL) group of compounds. In the present work, the yeast was shown to produce 63.7 g l⁻¹ SL when grown on a cheap fermentative medium containing sugarcane molasses, yeast extract, urea, and soybean oil. The partially purified SL was characterized and confirmed by Fourier-transform infrared (FT-IR) spectroscopy, ¹H and ¹³C nuclear magnetic resonance (NMR) and liquid chromatography–mass spectroscopy (LC-MS) analysis. The critical micelle concentration (CMC) and minimum surface tension of the produced SL in aqueous solution were found to be 59.43 mg l⁻¹ and 34.15 m Nm⁻¹, respectively. The emulsification activity and stability with kerosene oil and organic solvents viz. xylene, benzene, and hexadecane were also tested using the produced SL, which yielded better results compared to those reported in the literature.     

Pyrimidine and Pyrazole Linked Azetidin‐2‐ones: Entry to Novel Class of β‐Lactam Heterocycles

A novel series of pyrimidine/pyrazole linked β‐lactams have been synthesized in excellent yields using a simple and efficient methodology involving conjunction of different heterocyclic substrates. All the new products were characterized on the basis of various spectroscopic techniques viz. FT‐IR, ¹H NMR, ¹³C NMR, elemental analysis (CHN), ¹H‐¹H correlation spectroscopy (¹H‐¹H COSY) and mass spectrometry (EIMS) in representative cases. Furthermore, theoretical calculations have also been performed on representative compounds and the results were compared with Cefuroxime axetil (a broad spectrum antibacterial agent). The phenomenon of tautomerism was also observed which was confirmed by different NMR experiments (D₂O exchange study and ¹H‐¹H correlation spectroscopy).     

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.     

Sesquiterpene Lactones from Anthemis melanolepis

From the aerial parts of A. melanolepis, two new sesquiterpene lactones, melanolepin B ( = 1α,4β,8α‐trihydroxyeudesm‐11(13)‐en‐12,6α‐olide; 1 ) and melanolepin C (= 1α,10β‐epoxy‐8β‐hydroxygermacra‐4(15),11(13)‐dien‐12,6α‐olide; 2 ), were isolated, together with four known compounds, desacetyllaurenobiolide, dentatin A, taraxasterol, and (3S,5R)‐loliolide. Compound 1 was found to have the rare cis‐fused eudesmane skeleton. The structures of the isolated compounds were established by means of NMR (¹H, ¹H‐COSY, ¹H,¹³C‐HSQC, HMBC, NOESY) and MS analyses.     

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.     

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.     

13C and1H NMR spectroscopic characterization of titanium(IV) alkylperoxo complexes Ti(OOtBu)n(OiPr)4?n with n=1, 2, 3, 4

Using¹³C and¹H NMR spectroscopy, titanium(IV) alkylperoxo complexes Ti(OOtBu)_n(OiPr)_4−n with n=1, 2, 3 and 4 were characterized in the reaction of Ti(OiPr)₄ withtBuOOH in CH₂Cl₂ and CDCl₃.     

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.     

Synthesis of 2-aryl-6-(4-bromophenyl)-4-(2,2-dichlorovinyl)pyridines with the use of 1-aryl-5,5-dichloropenta-2,4-dien-1-ones

Heating 1-aryl-5,5-dichloropenta-2,4-dien-1-ones with 4-bromophenacylpyridinium bromide in AcOH in the presence of AcONH₄ gave 2-aryl-6-(4-bromophenyl)-4-(2,2-dichlorovinyl)pyridines. The reaction products were structurally characterized by¹H and¹³C NMR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 955–957, May, 2000.     

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.     

脯氨酸类N-酰胺衍生物的核磁共振研究

脯氨酸类衍生物结构独特,鲜有报道利用核磁共振（nuclear magnetic resonance,NMR）技术对氨基酸的手性进行鉴别.利用多种NMR技术:1H NMR、1H-1H同核位移相关谱（1H-1H COSY）、1H-1H质子全相关谱（1H-1H TOCSY）、1H-1H核Overhauser效应谱（1H-1H NOESY）、13C NMR、无畸变的极化转移增强法（DEPT135°）、1H-13C检出1H的异核单量子相干（1H-13C HSQC）和1H-13C检出1H的异核多键相关（1H-13C HMBC）,对脯氨酸类N-酰胺衍生物两种构象异构体的1H和13C NMR进行了全归属,确定了室温下在二甲基亚砜（DMSO）中L型和D型的顺反异构体以相同的比例同时存在.     

Two new ceramides from <Emphasis Type="Italic">Zephyranthes candida</Emphasis>

Two new ceramides were isolated from the bulbs of Zephyranthes candida. Their structures were established as (2S,3S,4R,13E)-1,3,4-trihydroxy-2-[(2′R)-2′-hydroxytetracosanoylamino]-13-octadecene, named zephyranamide A (1) and (2S,3S,4R)-1,3,4-trihydroxy-2-octacosanoylaminohexadecene, named zephyranamide B (2). The structures of the new compounds were elucidated by spectral techniques including ¹H NMR, ¹³C NMR, as well as HSQC, HMBC, DEPT, and COSY.     

15-O-Deacetylrhaposerin and rhaserin -- new components of a lactone mixture from Rhaponticum serratuloides

As part of our continuing studies of lactones from the aerial part of the plant Rhaponticum serratuloides, 15-O-deacetylrhaposerin and new guaianolide called rhaserin were isolated along with the well-known loliolide. The configuration of the C(17) asymmetric center in 15-O-deacetylrhaposerin was established by X-ray diffraction analysis. The molecular structure of rhaserin was determined based on the data from ¹H and ¹³C NMR spectroscopy (including 2D NMR spectroscopy) of this lactone and its 4,15-O-isopropylidene derivative.