Proanthocyanidins ofZiziphus jujuba

The catechin and proanthocyanidin compositions of the leaves and bark ofZiziphus jujuba have been studied over the vegetation periods. This has led to the isolation of 16 compounds, including 8 monomeric catechins — (–)-epiafzelechin, (–)-epicatechin, (–)-epigallocatechin, (–)-epicatechin gallate, (–)-epigal-locatechin gallate, (+)-catechin, (+)-catechin gallate, and (+)-gallocatechin; 4 dimeric proanthocyanidins — (–)-epiafzelechin-(4-8)-(–)-epicatechin, proanthocyanidin B-2, (–)-epicatechin-(4-8)-(–)-epigallocatechin, and (–)-epiafzelechin-(4-8)-(–)-epigallocatechin; and 4 oligomeric proanthocyanidins consisting of epiafzelechin, epigallocatechin, catechin, and epicatechin with different degrees of polymerization. Their structures have been established by a study of PMR and¹³C NMR spectra and the products of chemical transformation.The materials of this paper were presented at the Second International Symposium on the Chemistry of Natural Compounds (SCNC, Eskiehir, Turkey, October 22–24, 1996).Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 221–231, March–April, 1997.     

Catechins and proanthocyanidins ofAlhagi sparsifolia. I

Ten individual compounds have been isolated from the epigeal part ofAlhagi sparsifolia Shap. in various stages of vegetative growth. Their structures have been established by a study of PMR spectra, physicochemical properties, and the products of chemical transformations: (–)-epicatechin, (–)-epigallocatechin, (–)-epigallocatechin gallate, (+)-catechin, (+)-gallocatechin, proanthocyanidin B-2, (–)-epigallocatechin-(4–8)-(–)-epicatechin, epigallocatechin gallate-(4–8)-(–)-epicatechin, proanthocyanidin B-1, and (–)-epicatechin-(4–8)-gallocatechin.The materials of this paper were presented at the Second International Symposium on the Chemistry of Natural Compounds (SCNC, Eskiehir, Turkey, October 22–24, 1996).Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 232–237, March–April, 1997.     

Insect pheromones and their analogs

A four-stage asymmetric synthesis of (+)-disparlure [(7R,8S)-(+)-cis-methyl-7,8-epoxyoctadecane (V)] has been effected from 8-methylnon-2Z-en-l-ol (I), obtained by the carboalumination of acetylene with tris(5-methylhexyl)aluminum using the Sharpless reaction. The asymmetric epoxidation of (I), (Ar, mol. sieve A, (+)-DET, (iOPr)₄Ti, t-BuOOH, –15°C, 20 h; H₂O, 1 h, NaOH, –7°C, 30 min) gave 8-methyl-2S,3R-epoxynonan-l-ol (II), which was oxidized (kieselguhr-CrO₃-Py, 0°C, 2 h; 25°C, 2 h) to 8-methyl-2S,3R-epoxynonan-l-al (III). The coupling of (III) with n-C₈H₁₇CH=PPh₃ (–78°C, 1 h; 25°C, 15 h) gave 2-methyl-7R,8S-epoxyoctadec-9Z-ene (IV), the hydrogenation (H₂/5% Pd-C, 25°C, 5 days) of which led to (V) in admixture with an isomerization product. Compound (V) was isolated by HPLC. Substance, yield, [] _D ²⁵ : (II), 73, –2.75°; (III), 80, [80.8°; (IV), 50, +37.25°; (V), 50, +0.8°. The IR and PMR spectra of (II–IV), the¹³C NMR spectra of (II) and (III), and the mass spectrum of (IV) are given.Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 715–718, September–October, 1989.     

Insect pheromones and their analogues

A scheme has been developed for the synthesis of (R)-(–)-10-methyltridecan-2-one, the sex pheromone of the southern corn rootworm (Diabrotica undecimpunctata) using as the chiral synthon (R)-(+)-methylheptenal obtained by the hydroperoxide oxidation of the readily available (S)-(+)-dihydromyrcene.Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Russian Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 125–129, January–February, 1992.     

Calculations of silicooxygen ring vibration frequencies

In the work model calculations of the vibrations of ideally isolated silicooxygen rings (using PM3 method) have been carried out. three-, four-, and six-membered rings have been considered. It has been found that that the three-membered silicooxygen rings are flat and practically undeformed showing D_3h symmetry. The rings of higher number of ring members (i.e. n>3) are deformed to some extent. The deformation reveals itself most significantly in the Si–O–Si bond angles distribution. In the case of all the rings the bridging Si–O–Si bonds are ca. 0.02–0.04 Å shorter than the non-bridging Si–O⁻ bonds. Hypothetical IR spectra for all the rings considered have been also calculated. Analysis of these hypothetical spectra leads to the conclusion that the whole spectrum can be divided into four wavenumbers regions, 1200–1100 cm⁻¹ stretching Si–O(Si) vibrations; 1000–800 cm⁻¹ stretching Si–O⁻ vibrations; 800–600 cm⁻¹; the region in which a band characteristic of silicooxygen rings appears, and below 600 cm⁻¹ bending ⁻O–Si–O⁻ and (Si)O–Si–O(Si). It has been also found that as the number of ring members increases the ‘ring band’ shifts to lower wavenumbers: 725 cm⁻¹ for three-membered rings, 650 cm⁻¹ for four-membered rings and 610 cm⁻¹ for six-membered rings. Calculated spectra have been compared with the experimental spectra of cyclosilicates. They showed good agreement in the 1200–600 cm⁻¹ region. In the experimental spectra as well as in the calculated ones, with increasing the number of ring members the ‘ring band’ shifts towards lower wavenumbers.     

Study of the catechins and proanthocyanidins ofQuercus robur

More than 20 compounds have been isolated from the bark ofQuercus robur. Monomers: (–)-epicatechin, (–)-epicatechin gallate, (+)-catechin, (+)-catechin gallate, (+)-gallocatechin, (–)-epigallocatechin, and (–)-epigallocatechin gallate; dimeric proanthocyanidins: (+)-catechin-(4-8)-(+)-catechin, 3-O-galloyl-(+)-catechin-(4-8)-3-O-galloyl-(+)-catechin, 3-O-galloyl-(+)-gallocatechin-(4-8)-(+)-gallocatechin, (–)-epicatechin-(4-8)-3-O-galloyl-(–)-epigallocatechin gallate, 3-O-galloyl-(–)-epicatechin-(4-8)-3-O-galloyl-(–)-epigallocatechin, 3-O-galloyl-(–)-epigallocatechin-(4-8)-(+)-catechin; and oligomeric proanthocyanidins: D14-D19.Materials presented at the IInd International Symposium on the Chemistry of Natural Compounds (SCNC, Eskiehir, Turkey, October, 22–24, 1996).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. 6, pp. 819–833, November–December, 1997.     

Circular dichroism of quinoid pigments from Far Eastern representatives of the family Boraginaceae

The electronic absorption and circular dichroism (CD) spectra of ten natural and modified quinoid pigments are described. An assignment has been made of the dichroic absorption in the 250–600 nm region of the CD spectra of the pigments investigated. It has been shown that in the solution of stereochemical questions for such compounds the most informative region of the CD spectrum is the 250–350 nm interval.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 568–573, September–October, 1983.     

The structures of chimganin and chimgin

Summary The roots ofFerula tschimganica Lipsky have yielded two new compounds with the compositions C₁₈H₂₄O₄ (mp 85°C) and C₁₇H₂₂O₃ (mp 155°C), which have been calledchimganin andchimgin. On the basis of their UV, IR, and NMR spectra and the products of alkaline hydrolysis, it has been shown that chimganin is the ester of 4-hydroxy-3-methoxybenzoic acid and chimgin that of 4-hydroxybenzoic acid with (+)-borneol.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 59–63, January–February, 1972.     

Choice of the best region for channel-by-channel summation of estimating the intensity of single photopeaks

The influence of partial peak width integration on the statistical error has been investigated. It has been shown that integration of the central photopeak part —±(0.55–0.64) FWHM for narrow peaks and ±(0.50–0.53) FWHM for wide peaks-allows to decrease the statistical error 1.5–2.0 times in comparision with the TPA method. The results obtained are valid both for real photopeaks and for smoothed spectra. The theoretical results have been confirmed by experimental data.     

Differentiation and quality estimation of Cordyceps with infrared spectroscopy

Heretofore, a scientific and systemic method for differentiation and quality estimation of a well-known Chinese traditional medicine, ‘Cordyceps’, has not been established in modern market. In this paper, Fourier-transform infrared spectroscopy (FTIR) and two-dimensional correlation infrared spectroscopy (2D-IR) are employed to propose a method for analysis of Cordyceps. It has presented that IR spectra of real Cordyceps of different origins and counterfeits have their own macroscopic fingerprints, with discriminated shapes, positions and intensities. Their secondary derivative spectra can amplify the differences and confirm the potentially characteristic IR absorption bands 1400–1700 cm⁻¹ to be investigated in 2D-IR. Many characteristic fingerprints are discovered in 2D-IR spectra in the range of 1400–1700 cm⁻¹ and hetero 2D spectra of 670–780 cm⁻¹ × 1400–1700 cm⁻¹. The different fingerprints display different chemical constitutes. Through the three steps, different Cordyceps and their counterfeits can be discriminated effectively and their qualities distinctly display. Successful analysis of eight Cordyceps capsule products has proved the practicability of the method, which can also be applied to the quality estimation of other Chinese traditional medicines.     

The structure of fetidine

Summary Fetidine is a binary aporphine-benzyltetrahydroisoquinoline alkaloid. A structural formula for fetidine has been proposed on the basis of the isolation of (+)-laudanosine (IIIa) and (+)-isoboldine (IV) from the degradation of fetidine (I) with sodium in liquid ammonia.The obtaining of (+)-laudanosine and (+)-glaucine has established the absolute configuration of the two asymmetric centers of fetidine.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 1, pp. 43–48, 1966     

Synthesis,spectroscopic and magnetic properties of methoxo- bridged copper(II) complexes with 2-amino-4-methylpyridine as the ligand

Three new methoxo-bridged copper(II) complexes with 2-amino-4- methylpyridine as the ligand have been synthesized and characterized by elemental analyses, FTIR and electronic spectra, and by their magnetic properties. The complexes exhibit strong antiferromagnetic interactions at room temperature. The u.v.-vis spectra exhibits three absorption bands, which can attributed to d–d, L–M and –* transitions. The i.r. spectra indicates Cu2O2 ring vibrations in the 580–530cm–1 range. The magnetic properties of the [Cu2(2-amino-4-methylpyridine)4(O- Me)2](ClO4)2 complex has been investigated in the 5–270K range and a singlet-triplet energy gap (–2J) of 67cm–1 was observed. All complexes in the solid state are e.p.r.-silent and show no triplet spectrum; in fact a weak signal due to a monomeric impurity are observed. Frozen solution e.p.r. spectra suggest that the complexes dissociate when dissolved in DMF or DMSO.     

Identification of vitamins A, D and E by particle beam liquid chromatography-mass spectrometry

Particle beam (PB) high performance liquid chromatography (HPLC)-mass spectrometry (MS) has been studied to investigate its suitability for the analysis of fat-soluble vitamins, as an example of thermally labile substances. The PB LC-MS system has been used to detect and identify vitamins A, D and E in foods and multi-vitamin preparations. The qualitative performance of the PB interface has been evaluated by an examination of the working parameters. A rapid elution of the vitamins was obtained on a C8 reversed-phase column using an aqueous methanol mobile phase. Analyses have been carried out using both, electron (EI) and chemical (CI) ionization. Positive and negative-ion CI spectra of the compounds are discussed. When PB-MS conditions are optimized, the detection limits for the fat-soluble vitamins tested have been typically in the 0.6–25 ng range when using the selected-ion monitoring technique.     

Vibrational spectra of certain triphenylmethane dyes and their structure in solution

A combined analysis of two types of vibrational spectra (Raman and infrared) has proven the lactone structure of colorless solid preparations of phenolphthalein and thymolphthalein. It has been shown that phenolsulfophthalein, its alkyl derivatives, and bromcresol purple exist in the solid state primarily in the form of an intensely colored zwitterion; bromphenol blue and bromthymol blue exist primarily in the form of a colorless sultone. For the ionized forms of triphenylmethane dyes (cationic and anionic chromophore systems) vibrations with a frequency near 1360 cm^–1 are characteristic in the IR spectra and also in the Raman spectra.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 6, pp. 688–698, November–December, 1990.     

Revised vibrational band assignments for the experimental IR and Raman spectra of 2,3,4-trifluorobenzonitrile based on ab initio, DFT and normal coordinate calculations

In the present study, a systematic vibrational spectroscopic investigation for the experimental IR and Raman spectra of 2,3,4-trifluorobenzonitrile (TFB), aided by electronic structure calculations has been carried out. The electronic structure calculations – ab initio (RHF) and hybrid density functional methods (B3LYP) – have been performed with 6-31G* basis set. Molecular equilibrium geometries, electronic energies, IR intensities, harmonic vibrational frequencies, depolarization ratios and Raman activities have been computed. The results of the calculations have been used to simulate IR and Raman spectra for TFB that showed excellent agreement with the observed spectra. Potential energy distribution (PED) and normal mode analysis have also been performed. The assignments proposed based on the experimental IR and Raman spectra have been reviewed. A complete assignment of the observed spectra has been proposed.     

A sesquiterpene lactone-semopodin-from the seeds ofFerula oopoda

Conclusions From the seeds ofFerula oopoda (Boiss et Buhse) Boiss. a new sesquiterpene lactone with mp 177–178° C has been isolated which has been given the name semopodin. On the basis of the NMR, UV, and IR spectra semopodin has been ascribed the probable structure I or II.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 4, pp. 241–244, 1969     

Far-infrared spectrum,barrier to internal rotation,ro structure,and ab initio calculations for acetylacetylene

The far-infrared spectrum has been recorded from 50 to 360 cm^–1 at a resolution of 0.10 cm^–1 for acetyiacetylene (1-butyne-3-one], CH₃C(O)CCH. The fundamental methyl torsion has been observed at 117.94 cm^–1, from which a periodic barrier to internal rotation has been calculated to be 346 cm^–1 (989 cal mol^–1]. Infrared spectra (3500-50 cm^–1] of the gas and solid and the Raman spectra (3500-100 cm^–1) of the gas, liquid, and solid are reported. Utilizing previously reported rotational constants for three isotopic species,r _o structural parameters have been determined for the heavy-atom skeleton. The fundamental vibrational frequencies, barrier to internal rotation, and structural parameters that have been obtained experimentally are compared to those obtained from ab initio Hartree-Fock calculations employing 3-21G, 6-31G, and DZ basis sets and to the corresponding quantities for some similar molecules.     

Infrared and Raman spectra, conformational stability, normal coordinate analysis, ab initio calculations, and vibrational assignment of 1-fluoro-1-methylsilacyclobutane

The infrared (3500–40 cm⁻¹) spectra of gaseous and solid 1-fluoro-1-methylsilacyclobutane, c-C₃H₆SiF(CH₃), have been recorded. Additionally, the Raman spectrum (3500–30 cm⁻¹) of the liquid has been recorded and quantitative depolarization values have been obtained. Both the axial and equatorial (with respect to the methyl group) conformers have been identified in the fluid phases. Variable temperature (−55–−100°C) studies of the infrared spectra of the sample dissolved in liquid xenon have been carried out. From these data, the enthalpy difference has been determined to be 267±10 cm⁻¹ (3.19±0.12 kJ mol⁻¹), with the axial conformer being the more stable form and the only conformer remaining in the polycrystalline solid. A complete vibrational assignment is proposed for the axial conformer and many of the fundamentals for the equatorial conformer have also been identified. The vibrational assignments are supported by normal coordinate calculations utilizing ab initio force constants. Complete equilibrium geometries have been determined for both rotamers by ab initio calculations employing the 6-31G* and 6-311++G** basis sets at the levels of restricted Hartree–Fock (RHF) and/or Moller–Plesset (MP) to second order. The results are discussed and compared to those obtained for some similar molecules.     

Alkaloids of a new type fromSophora alopecuroides L.

Summary The structures of aloperine and allylaloperine (fromSophora alopecuroides L.) — alkaloids of a new structural type for the genusSophora — have been established by chemical and spectral methods. A number of parameters, NMR spectra, and mass spectra characterizing this class of compounds has been obtained. The partial synthesis of allylaloperine has been performed.All-Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 30–37, January–February, 1975.     

Modified oxidation of (+)-3-carene by potassium permanganate

The oxidation of (+)-3-carene under the conditions of phase-transfer catalysis has been studied. It has been shown that when the reaction is performed in acetic acid the keto acids (IIa) and (IIIa) and (–)-3-hydroxycaran-4-one (IV) are formed.Institute of Organic Chemistry, Urals Branch, Russian Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 338–340, May–August, 1992.