Development of a method for determining bornyl acetate in the products of the processing of Abies sibirica

Summary The conditions for the reaction of esters—bornyl acetate—with an alkaline solution of hydroxylamine have been studied by the method of steepest ascent. A method has been developed for determining esters in a CO₂ extract ofAbies sibirica.Krasnodar Scientific-Research Institute of the Food Industry. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 303–306, May–June, 1976.     

Synthesis of polybrominated diphenyl ethers of marine origin

Polybrominated diphenyl ethers — antimicrobial metabolites of the marine spongeDysidea fragilis — have been obtained by the reaction of 2,3,5-tribromonitrobenzene with 3,5-dibromo-2-methoxyphenol and the reaction of brominated diphenyliodonium salts with brominated phenols.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 352–354, May–June, 1993.     

Reaction of 4,6-dimethylpyrimidine with chlorides of aromatic carboxylic acids

The reaction of methyl groups with acyl chlorides is described for the first time in the pyrimidine series. The corresponding ketones — 6-methyl-4-phenacylpyrimidines — have been obtained from 4,6-dimethylpyrimidine and chlorides or aromatic carboxylic acids. A possible mechanism of the reaction is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp, 1132–1135, August, 1973.     

Products of phototransformation of provitamins D4 obtained from a mutant Saccharomyces cerevisiae yeast. I. Irradiation in ethanol

The composition of the photolytic mixture formed on the irradiation of provitamin D₄ has been studied. Together with the main reaction products — vitamin D₄ and provitamin D₄ — a number of by-products were formed the structures of which have been established from their spectral characteristics.Lensoviet Leningrad Technological Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 247–254, March–April, 1989.     

Synthesis of indoles from pyridinium salts 5. Secondary amines in the reaction of 3-nitropyridinium salts with acetone

The use of secondary amines in the reaction of 3-nitropyridinium salts with acetone makes it possible to isolate stable intermediates in the formation of indoles — (o-N,N-dialkylaminobenzyl)ketones — and to observe new reaction pathways — the formation of bisindolylpropanes and p-nitroanilines.See [1] for Communication 4.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1213–1221, September, 1988.     

Chemical synthesis and enzymatic assembly of fragments of the DNA coding immunodominant epitopes of human immunodeficiency virus

More than twenty 13- to 55-membered oligo(poly)nucleotides have been synthesized by the H-phosphonate solid-phase method in the manual variant using an original procedure. From the oligonucleotides obtained, seven DNA duplexes coding immunodominant epitopes of HIV-1 proteins have been formed: 598–609 and 737–748 gp41, 91–115 and 105–115 gag, and 940–951 pol and a number of its mutants. The ligase assembly and polymerization of the DNA duplexes obtained has been carried out. The efficiency of ligation amounted to from 60 to 90%. The possibility of their directed polymerization was determined by the flanking of the duplexes by partially completed half-sites of restrictases BamHI and XhoI.Abbreviations adopted: HIV-1 — human immunodeficiency virus, type 1; (+)-chain — the coding chain — and (–)-chain the chain complementary to the coding chain of the DNA duplex; CPG — controlled-pore glass; PAAG — polyacrylamide gel; Py — pyridine.D. I. Ivanovskii Institute of Virology, USSR Academy of Medical Sciences, Moscow. V. A. Engel'gardt Institute of Molecular Biology, USSR Academy of Sciences, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 393–399, May–June, 1990.     

Insect pheromones and their analogues

A stereospecific synthesis has been achieved of tetradec-11E-enal and of tetradec-11E-en-l-ol and its acetate — components of the pheromones of many species of insects of the order Lepidoptera — from the readily available undecenoic acid, using the Knoevenagel reaction and catalytic hydroalumination.Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Russian Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 272–276, March–April, 1992.     

Reactions of lycoctonine alkaloids with acetic anhydride and p-toluenesulfonic acid

The reactions of alkaloids having a 7,8-diol system — lycoctonine, browniine, and dihydromonticoline — with acetic anhydride and p-toluenesulfonic acid have been studied. The optimum conditions for this reaction, leading to anhydro compounds, have been found.Abuali ibn Sino [Avicenna] Tadzhik State Medical Institute, Dushanbe; Institute of Chemistry, Baskir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 545–547, July–August, 1991.     

New reaction in the acridine series

A new reaction in the acridine series — reaction of its salt or the base with the salts or bases of N-heterocyclic compounds containing an active methyl group in the presence of sulfur — was investigated. It is shown that 9-acridinylheterylmethanes are formed as a result of this reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1384–1386, October, 1970.     

Quantum chemical investigation of the reaction of phosphine with alcohol in the coordination sphere of platinum(IV) and platinum(II)

The CNDO method has been used to investigate a new autocatalytic reaction of reduction of alcohol solutions of platinum(IV) halides by phosphine, leading to the formation of products of O-phosphorylation — trialkyl phosphites — at low temperature (20–50°C) and products of C-phosphorylation — trihydroxyalkylphosphines — at high temperature (60–90°C). It was shown by comparing the metalligand and ligand-ligand bond energies in haloalcohol phosphine complexes of platinum(IV) and platinum(II) that alkoxylation proceeds through a step of deprotonation of the alcohol with nucleophilic assistance and introduction of phosphine at the metal-oxygen bond, whereas hydroxyalkylation includes a step of -elimination of alkoxide hydrogen and insertion of phosphine at the metalcarbon bond. Autocatalysis is due to the fact that the indicated key steps on platinum(II) are significantly more profitable with respect to the energy difference of the bonds broken (metal-ligand) and formed (ligand-ligand).Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 4, pp. 301–312, July–August, 1992.     

Some characteristics of the alkali-soluble protein from the red alga Furcellaria fastigiata

Summary From the red agar-bearing alga furcellaria we have isolated an alkali-soluble protein. Its aminoacid composition and N-terminal acid — arginine — have been determined. It has been shown to belong to the group of glycoproteins. One of the possible types of carbohydrate — protein bonds is a O-glycosidic bond.Odeassa Institute of Building Engineering. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 400–404, May–June, 1975.     

Quantum-chemical study of the mechanism of the influence of cations of d metals on the rate of the oxidation of phosphine by Cu(II) halides

A hypothesis concerning the formation of associates between intermediate complexes and cations has been introduced in order to account for the experimental dependence of the rate constant of the oxidation of phosphine by Cu(II) halides on the nature of the cation in the salt MCl₂ (M = Mn, Co, Ni). The quantum-chemical characteristics of the systems formed have been calculated by the Mulliken—Wolfsberg—Helmholz-SCCC method. It has been shown that the correct correlation between the electronic properties of the intermediates and the rate constant of the reaction upon the variation of M can be obtained only for a specific mechanism for the addition of M²⁺ to the complex.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 21, No. 6, pp. 718–722, November–December, 1985.     

Polymorphic transformations of silicon dioxide obtained in reaction media of different chemical types

A study has been made of polymorphic transformations of silicon dioxide obtained by the sol—gel method from alkoxide reagents, as influenced by the nature of the reaction medium and the water/alkoxide ratio. It has been shown that the nature of the reaction medium is an extremely important parameter in controlling the polymorphic transformations of silicon dioxide.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 31, No. 4, pp. 254–258, July–August, 1995.     

Determination of stichoposides in the body of the holothurianStichopus japonicus

A method has been developed for the quantitative determination of triterpene glycosides — stichoposides — in the tissues of the Far Eastern holothurianStichopus japonicus Selenka. The quantitative determination of the combined triterpene glycosides was based on the isolation of a glycosidic fraction from an ethanolic extract on a column of Polikhrom-1 with subsequent spectrophotometry at 268 nm of the product formed as the result of the reaction of the glycosides with 1 N NaOH. The quantitative determination of the individual glycosides is based on the densitometry of slides or thin-layer chromatography in silica gel with the aid of a Lyuman-IUF-1 luminescence microscope.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Pacific Ocean Institute of Oceanography and Fisheries. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 56–59, January–February, 1984.     

Chemical modification of the tryptophan residues of the L-asparaginase of E. coli with N-bromosuccinimide

Summary The role of the tryptophan residues in the L-asparaginase molecule has been studied by the method of chemical modification with N-bromosuccinimide, and it has been established that in an acid medium this reagent modifies all four tryptophan residues present in the molecule, completely suppressing the activity of the enzyme.The substrate — L-asparagine — and a competing inhibitor — S-benzyl-N-benzyloxycarbonyl-L-cysteine — protect the L-asparaginase from the action of N-bromosuccinimide, which shows the role of the tryptophan in the catalytic center of the L-asparaginase.Institute of Organic Synthesis, Academy of Sciences of the Latvian SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 228–231, March–April, 1975.     

Triterpene and steroid glycosides of the genusMelilotus and their genins III. Funkioside B and protodioscin from the seeds ofMelilotus tauricus

Two steroid glycosides belonging to the furostan series — funkioside B and protodioscin — have been isolated from the seeds of the plantMelilotus tauricus (Bieb.).Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 766–770, November–December, 1994.     

Synthetic analogs of Peganum alkaloids VI. Photochemical oxidation of 2,3-polymethylene-quinazoline derivatives

The rates of the photochemical oxidation of quinazoline alkaloids — deoxypeganine, peganine, pentamethylenequinazoline, and peganol — to the corresponding oxo derivatives have been studied. It has been shown by HPLC that the oxidation of deoxypeganine proceeds through a stage of the formation of a carbinolamine (peganol); in the case of its hydrochloride, the reaction takes place by the same scheme but four times more slowly. Tetra- and pentamethylenequinazolines have been synthesized and information on their melting points in the literature has been corrected. In the series trimethylenequinazoline-pentamethyl-enequinazoline-tetramethylenequinazoline the stability falls from left to right.Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 528–532, July–August, 1991.     

Synthesis of the acetate of (±)-2,6-dimethylhepta-1,5-dien-3-ol — The racemic form of the sex pheromone of Pseudococcus comstocki

4-Methylpent-3-enal has been synthesized by the dehydration of trans-2-(1-hydroxy-1-methylethyl)-1-methoxycyclopropane, and this has been brought into reaction with propen-2-ylmagnesium bromide. Acetylation of the carbinol so formed gave the acetate of (±)-2,6-dimethylhepta-1,5-diene-3-ol — the racemic form of the sex pheromone of the Comstock mealybug.Scientific-Research Institute of Physicochemical Problems, V. I. Lenin Belorussian University, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 747–748, September–October, 1988.     

Effect of an external periodic field on the rate of chemical reactions

The rates of direct and concert passages of nuclei through a potential barrier in an external periodic field were determined within a generalized Slater model of thermal dissociation of multiatomic molecules. The external field accelerated direct and — to a much greater degree — concert passages. The curves of the efficiency of the concert mechanism of the chemical reaction as a function of the field amplitude were estimated.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 29, No. 2, pp. 127–132, March–April, 1993.     

Synthesis of 5-(5-R-2-furyl)thiazole derivatives by the reaction of 2-(5-R-furfuryl)thiuronium salts with acetic anhydride

2-Acetamide-4-methyl-5-(5-R-2-furyl)thiazoles were obtained by the reaction of 2-(5-R-furfuryl)thiuronium salts with acetic anhydride. The reaction intermediates — 2-(5-R-furfuryl)-1,3-diacetylthioureas — were isolated and characterized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 557–562, April, 1990.