Pheromones of coleoptera. Communication 6. Synthesis of R,Z-14-methyl-8-hexadecenal (cis-trogodermal)

Conclusions The simple synthesis of optically active R,Z-14-methyl-8-hexadecenal (cis-trogodermal), the principal components of the aggregation pheromone ofTrogoderma granarium, was accomplished. The synthesis was based on the use of R-1-bromo-4-methylhexane and Z-4-chloro-2-buten-1-ol as the sources of the chiral and olefin fragments.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 906–910, April, 1987.     

The light 1P-shell nuclei

The binding energies and other characteristics of the light 1P-shell nuclei (N, Z8) are calculated. We use the method denoted as modified oscillator shell model (MOSM), proposed by one of the authors (Nguyen tien Nguyen: Czech. J. Phys. B31 (1981) 16). We succeed in choosing the parameter set of the Skyrme-type force, which gives satisfactory and interesting results.On leave fromFaculty of Physics, Hanoi University, Vietnam.The authors would like to thank I. Wilhelm for the useful discussion.     

Synthesis of 20-deoxoluteone

20-Deoxoluteone has been synthesized from sclareol. Sclareol was brominated with phosphorus tribromide to form a mixture of primary allyl bromides, from which, by the malonic synthesis, a mixture of bicyclogeranylgeranylacetic acids was obtained which was cyclized with fluorosulfonic acid to form a mixture of two diastereomeric -lactones. The predominating lactone was converted by successive reduction with lithium tetrahydroaluminate, oxidation with oxalyl chloride in dimethyl sulfoxide, reaction with methylmagnesium iodide, and oxidation by the chromium trioxide/pyridine complex into 20-deoxyluteone.Institute of Chemistry, Moldavian SSR Academy of Science, Kishinev. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 346–353, May–June, 1990.     

Emploi des thiocarbohydrazones en analyse organique fonctionelle

Résumé Le thiocarbohydrazide est un réactif d'accès facile précipitant quantitativement les aldéhydes et quelques cétones. Les points de fusion sont nets. Les précipités formés se prêtent à la gravimétrie. Nous avons étudié avec la thermobalance leur domaine de stabilité et fourni la température à ne pas dépasser pour le séchage à poids constant.

---

Summary Thiocarbohydrazide is a readily available reagent which quantitatively precipitates aldehydes and some ketones. The melting points are sharp. The resulting precipitates are suitable for gravimetry. Their regions of stability have been investigated with the thermobalance and the temperatures which should not be exceeded in drying to a constant weight have been found.

---

Zusammenfassung Thiocarbohydrazid ist ein leicht zugängliches Reagens zur quantitativen Fällung der Aldehyde und mancher Ketone. Die Schmelzpunkte der Niederschläge sind scharf. Diese eignen sich zur gravimetrischen Auswertung. Ihre Stabilität wurde mit Hilfe der Thermowaage untersucht und die Höchsttemperaturen für ihre Trocknung bis zur Gewichtskonstanz bestimmt.

     

Low frequency limits of third-order harmonic coefficients for atomic hydrogen in any level of discrete energy spectrum

In this paper the analytical expression is derived for the third-order optical harmonic coefficients x _abcd ^v (,,) of the atomic hydrogen at very low frequencies 0 in many level of the discrete energy spectrum.The author expresses his thank to Prof. Nguyen Van Hieu for suggesting the problem and fruitful discussions.     

Book Review

Abstract

A Guide to Organophosphorus Chemistry, by Louis D. Quin, an internationally recognized authority, published by John Wiley and Sons (http://www.wiley.com/chemistry) ISBN 0-471-31824-8, $94.95, 394pp.

Aminophosphonic and Aminophosphinic Acids: Chemistry and Biological Activity. Editors: Valery P. Kukhar (Ukrainian Academy of Sciences) and Harry R Hudson (University of North London). Published by John Wiley and Sons Ltd., Chichester, UK, on 31 March, 2000. ISBN 0 471-89149-5, 175.00 Pounds sterling, 634 pages.

Phosphorus Ylides. Chemistry and Application in Organic Synthesis, by Oleg I. Kolodiazhnyi. Published by Wiley-VCH, 1999, ISBN 3-527-29531-3, 220SF, 555 pages.     

Synthesis and Biological Evaluation of a Novel Series of (Hydroxyphenyl)-Aminophosphonates

Abstract

Elevated plasma cholesterol is now well established as a major risk factor for cardiovascular diseases. It has also been shown that the oxidation of low density lipoproteins leads to the formation of foam cells which contribute to the deposition of cholesterol in arteries.     

Thermostable Trioxane-Dioxolane Copolymers Obtained with Boron Trifluoride: Acrylonitrile Complex as Initiator

Trioxane was copolymerized with small amounts of dioxolane in benzene in the presence of a boron trifluoride:a crylonitrile complex as initiator. The kinetics of reactions was expressed in terms of topoenergetic principles. The copolymerizations had no induction periods and the maximum reaction rate was found proportional to the square of both the initiator and monomers concentrations. A zwitterionic mechanism is suggested for initiation. The activation energy for the system with 5% dioxolane was determined as 18.3 kcal/mol. The melting behavior of the copolymers is briefly discussed as a function of the dioxolane initial content, and is indicative of the amorphous-crystalline coupling phenomenon. The copolymers with ～ 5% dioxolane are thermostable in air up to 250%deg; and are recommended for practical purposes.     

Reentrant phenomenon in cyanoaryl alkylthioxybenzoates and cyanobenzoyloxyphenyl alkylthiobenzoates

Abstract

Three new series of cyanoaryl 4-alkylthioxybenzoates have been synthesized and characterized. The 4-cyanophenyl series displays only transient mesomorphic properties while the 6-cyano-2-naphthyl and 4-cyanobiphenyl series exhibit the classical nematic and smectic A phases; a reentrant nematic phase is also found in the latter. Two other new series in which the position of the sulphur atom in the central rigid core has been varied were also prepared: the 4–[4′-cyanobenzoyloxy]-phenyl 4-alkylthiobenzoates and 4–[4′-alkylbenzoyloxy]phenyl 4-cyanothiobenzoates. As in the analogous benzoate series, the reentrant phenomenon with the sequence C, S_Are, N_re, S_A, N, I is observed with the nonyl derivatives. Comparisons between the alkoxybenzoates and the alkylthioxybenzoates are given.