Essential Oil Constituents of Satureja boissieri from Turkey

Water-distilled essential oil from the aerial parts ofS. Boissieriwas analyzed by GC/MS. Forty - five components were characterized representing 97% of the oil. The main components were identified as carvacrol (40.8%),-terpinene (26.4%), andp-cymene (14.5%).     

Effects of α-tocopherol and its acetate on the hydrolytic activity of phospholipase D in egg yolk phosphatidylcholine bilayers

Effects of -tocopherol (Toc) and -tocopherol acetate (TocA) on the hydrolysis activity of phospholipase D (fromStreptomyces chromofuscus) were studied in small unilamellar vesicles (SUV) of egg yolk phosphatidylcholine (PC). Choline produced in the reaction was monitored by use of a choline oxidase — oxygen electrode. Addition of 18 mol% Toc into SUV (2 mM PC) brought about a twofold rate of choline production. On the other hand, the effect of 18 mol% TocA in SUV was very small. The apparent maximum velocity,V _max(app), increased by addition of Toc in SUV. The apparent Michaelis constant,K _m(app), was unchanged by addition of Toc and TocA in SUV. The Toc and TocA molecules did not have significant effects when PC was solubilized in the micelles of heptaethylene glycol dodecyl ether. The effects of Toc and TocA are, therefore, not due to specific ones on the enzyme itself, but rather upon the bilayer-organization of the substrate. Measurements of spreading pressure showed complete miscibility of PC and Toc, and limited mutual solubility of PC and TocA, suggesting stronger attractive interactions between Toc and PC than those between TocA and PC in the bilayers.     

Selective esterolysis of nitrophenyl acetates in crystalline α-cyclodextrin complexes

The esterolysis ofm-nitrophenyl acetate (mNPA) andp-nitrophenyl acetate (pNPA), complexed with -cyclodextrin, was investigated in the solid state. At 117 and 140°C, the initial half-times ofmNPA esterolysis were 30 and 24 h, respectively, whereasp NPA esterolysis was undetectably slow. At 117°C, themNPA reaction proceeded to completion, and cyclodextrin acetate andm-nitrophenol products were identified. At 140°C,the initial rate was followed by a slow phase with a half-time of 130 h, evidently due to a structural change in the complex. Themeta/para selectivity of the solid-state reaction is considerably enhanced over the selectivity reported in aqueous solution.     

COMPOSITION OF THE ESSENTIAL OIL OF Haplophyllum myrtifolium

The chemical composition of the essential oil ofHaplophyllum myrtifoliumBoiss., endemic to Turkey, was examined by GC/MS. Ninety-seven compounds were characterized with linalool (12.8%), -caryophyllene (10.3 %), and methyleugenol (5.9 %) as the main constituents.     

COMPOSITION OF THE ESSENTIAL OIL OF Arbutus unedo

Water-distilled essential oil from leaves ofArbutus unedoL. of Turkish origin was analyzed by GC/MS. Thirty-seven constituents were characterized with (E)-2-decenal (12.0 %), -terpineol (8.8 %), hexadecanoic acid (5.1 %), and (E)-2-undecenal ( 4.8 %) as the major constituents.     

Porphyrins. 38. Reaction of Porphyrins Containing Hydroxy(alkoxy)ethyl or Alkoxymethyl Substituents with Nucleophiles in the Presence of Zinc Acetate. A Novel, Promising Method for the Modification of Porphyrins on the Periphery of the Macrocycle

Porphyrins which contain 1-hydroxy(alkoxy)ethyl or alkoxymethyl substituents on the periphery of the macrocycle (i.e. formally able to yield benzyl type carbocations) react with nucleophiles (4-tert-butylphenol or the -diketones acetylacetone, benzoylacetone, dibenzoylmethane, or 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione) in the presence of excess zinc acetate. They give high yields of the corresponding addition products, which are the zinc complexes of porphyrins with a 1-(4-tert-butylphenoxy)ethyl substituent or with substituents containing -diketone residues.     

Some peculiarities of the preparative electroreduction of allyldimethylsulfonium salts

The influence of electrode potential and (6-acetoxy-1-isopropenyl-4-methylhexyl)dimethylsulfonium perchlorate concentration on the yield of -citronellyl acetate and the selectivity of reduction were studied. A mechanism of electrolytic reduction involving preparative electrolysis on a mercury cathode at potentials of the first and second waves was proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1255–1260, July, 1994.     

Artificial hydrolase using modified dimethyl-β-cyclodextrin

The first successful method for modification of dimethyl--cyclodextrin (-DMCD) was demonstrated by the synthesis of a new artificial hydrolase (2) and the enzymatic activities of 2 were investigated.2 caused an 1100-fold increase in the rate of hydrolysis ofp-nitrophenyl acetate at pH 7.2, whereas unmodified-DMCD depressed the reaction. The kinetic pK _a of2 was 7.2, and theK _m of2 was independent of pH values.2 hadpara-selectivity for the hydrolysis of nitrophenyl acetate isomers.     

Asymmetric michael addition of aromatic thiols to 2-cyclohexenone and maleic acid esters via formation of crystalline cyclodextrin complexes

The asymmetric Michael addition of aromatic thiols to 2-cyclohexenone and maleic acid esters has been carried out by utilizing their crystalline cyclodextrin complexes suspended in water. The best chiral induction, 30% enantiomeric excess (ee), was achieved in combinations of 2-cyclohexenone and octyl maleate with the crystalline -cyclodextrin complex of benzenethiol (method A) to afford (S)-3-phenylthiocyclohexanone and (S)-octyl-2-phenylthiosuccinate, respectively, whereas the reaction of benzenethiol with 2-cyclohexenone included in -cyclodextrin (method B) inversely induced the chiral recognition to give the (R)-adduct with 4–9% ee.     

Improved synthesis of 6-deoxy-1,2-O-isopropylidene-β-L-talofuranose and 6-deoxy-1,2-O-isopropylidene-β-L-idofuranose

Summary The key step in the preparation of 6-deoxy-1,2-O-isopropylidene--L-talofuranose (7) and 6-deoxy-1,2-O-isopropylidene--L-idofuranose (13) is the selective exchange of the 6-O-mesyl rest of 3-O-acetyl-5,6-O-dimesyl-1,2-O-isopropylidene--D-allofuranose (4) and 3-O-acetyl-5,6-O-dimesyl-1,2-O-isopropylidene--D-glucofuranose (10) by acetate group (potassium acetate/18-crown-6).

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Ein neuartiger und präparativ nützlicher Zugang zu 6-Desoxy-1,2-O-isopropyliden--L-talofuranose und 6-Desoxy-1,2-O-isopropyliden--L-idofuranose

Zusammenfassung Schlüsselschritt bei der Herstellung von 6-Desoxy-1,2-O-isopropyliden--L-talofuranose (7) und 6-Desoxy-1,2-O-isopropyliden--L-idofuranose (13) ist der selektive Austausch der primären Mesyl-Gruppe in 3-O-Acetyl-5,6-O-dimesyl-1,2-O-isopropyliden--D-allofuranose (4) und 3-O-Acetyl-5,6-O-dimesyl-1,2-O-isopropyliden--D-glucofuranose (10) durch den Acetat-Rest in Gegenwart von Kaliumacetat/Kronen-Ether.

     

Binding energies of metal monocations to Β-lactones and Β-lactams. A theoretical study of cyclization effects

Ab initio calculations have been performed to study the association of-propiolactam and-propiolactone and their aliphatic analoguesN-methyl acetamide and methyl acetate with different metal monocations: Li⁺, Na⁺, Mg⁺, and Al⁺, in an effort to investigate cyclization effects on the gas-phase basicities of amides and esters, when the reference acid is not a proton. Similarly to what was found for protonation,N-methyl acetamide and-propiolactam are more basic than methyl acetate and-propiolactone, when the reference acids are the aforementioned metal monocations. However, cyclization effects on the corresponding binding energies for both kind of compounds do not parallel those observed for protonation energies, and-lactone is as basic as methyl acetate when the reference acid is Li⁺ and slightly more basic than methyl acetate when the attaching ion is Na⁺. This implies that when the interactions of the bases with the reference acids are essentially electrostatic the reactivity patterns change with respect to those observed when the interactions are essentially covalent.     

2,2′-Diphenyl-Δ3,3′-bi-3H-indole-1,1′-dioxide: Molecular interactions and crystal structure

The Dinitrone 2,2-diphenyl-^3,3-bi-3H-indole-1,1-dioxide acts as a demethylating and dehydrogenating agent. The mechanism of interaction of the dinitrone with donors and acceptors does not involve intermediate charge-transfer complexes probably due to a self association between dinitrone molecules (as supported by X-ray determinations). The crystal structure of the dinitrone was obtained by direct methods;a=9.967 (2),b=19.817 (3),c=10.875 (2) Å, =111.2 (2)°, space group P2₁/n. The finalR andR _w were 0.089 and 0.063 for all measured reflexes.

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2,2-Diphenyl-^3,3-bi-3H-indol-1,1-dioxid: Molekulare Wechselwirkungen und Kristallstruktur

Zusammenfassung Das Dinitron 2,2-Diphenyl-^3,3-bi-3H-indol-1,1-dioxid wirkt als Demethylierungs- und Oxydationsmittel. Die Wechselwirkung des Dinitrons mit Elektronen-Acceptoren und Elektronen-Donatoren geht wegen der Selbstassoziation zwischen den Dinitron-Molekülen ohne die dazwischenliegende Bildung eines Charge-Transfer-Komplexes vor sich; das wird auch von Röntgenstrukturuntersuchungen gestützt. Die Kristallstruktur wurde mit direkten Methoden ermittelt:a=9.967 (2),b=19.817 (3),c=10.875 (2) Å; =111.2 (2)°. P2₁/n. Die endgültigen WerteR undR _w waren 0.089 und 0.063 für alle gemessenen Reflexe.

     

VOLATILE COMPOUNDS FROM Haplophyllum myrtifolium

The volatile fractions of the petroleum ether extract and of the alkaloid extract ofHaplophyllum myrtifoliumBoiss., endemic to Turkey, were trapped by using the Solid Phase Micro Extraction (SPME) technique and analyzed by GC/MS. Forty-seven compounds were characterized from the petroleum ether extract of the aerial parts with -caryophyllene (14.6 %), decane (11.4 %), and -phellandrene (7.0 %) as the major components. Chavibetol (21.9 %), eugenol (19.1 %), methyleugenol (10.8 %), trans-linalool oxide (7.1 %) and -cyclocitral (6.0 %) were identified as the major components among the forty-two compounds characterized in the chloroform eluate of the alkaloid extract.     

Essential Oil of Arischrada korolkowii from the Chatkal Mountains of Uzbekistan

The herbal parts of Arischrada korolkowii (Regel et Schmalh.) Pobed. (Lamiaceae) growing in Uzbekistan were hydrodistillated to yield 1.1% of essential oil. The essential oil was analyzed by GC/MS. Eighty eight compounds were characterized representing 98% of the essential oil with 1,8-cineole (29.3%), camphor (9.8%), -caryophyllene (8.5%), bornyl acetate (7.7%), caryophyllene oxide (7.2%), and borneol (5.6%) as the main constituents.     

A kinetic method for the direct determination of cellobiose hydrolysis by β-glucosidases

TheSomogyi—Nelson colorimetric method is applied in a new manner which is more suitable for following the kinetics of cellobiose hydrolysis catalyzed by -glucosidase (EC 3.2.1.21). TheSomogyi—Nelson colour reagent, which is a mixture of the solutions of the reagent ofSomogyi and that ofNelson in a volume ratio of 1:1, is added to the enzyme-substrate solution at the very start of the reaction. The colour reagent reacts with the product (D-glucose). Under the reaction conditions (0.1M acetate buffer,pH = 5.0 and temperature 37°C) the colour reagent does not affect the enzyme activity. The method excludes any inhibition of the product, owing to the continuous removal of the latter by the colour reagent. The method suggested has been applied to monitor cellobiose hydrolysis with -glucosidase, contained in four cellulase enzyme preparations from various fungal sources. The values of theMichaelis parameters (Km, V) were determined.

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Eine kinetische Methode zur Verfolgung der Hydrolyse von Cellobiose durch ß-Glucosidasen

Zusammenfassung Die kolorimetrische Methode nachSomogyi undNelson wird nach einem neuen Verfahren zur Verfolgung der Kinetik der hydrolytischen Spaltung von Cellobiose, katalysiert durch -Glucosidase (EC 3.2.1.21), angewandt. Das Farbreagenz nachSomogyi undNelson (Mischung der Reagenzien vonSomogyi undNelson im Volumenverhältnis 1:1) wird der Enzym-Substrat-Lösung zu Beginn der Reaktion hinzugefügt. Das Farbreagenz tritt mit derD-Glukose in Reaktion, wobei unter den gegebenen Reaktionsbedingungen (0,1M Azetatpuffer,pH = 5,0 und 37°C) die Enzymaktivität nicht beeinflußt wird. Die entwickelte Methode wurde zur Verfolgung der Hydrolyse von Cellobiose durch ß-Glucosidasen, die in vier Enzympräparaten aus verschiedenen Pilzstämmen enthalten waren, angewandt. Es wurden dieMichaelis-Parameter (Km, V) bestimmt.

     

Enhanced dissolution and oral bioavailability of α-tocopheryl esters by dimethyl-β-cyclodextrin complexation

Inclusion complexation of heptakis (2,6-di-O-methyl)--cyclodextrin (DM--CyD) with -tocopheryl acetate and -tocopheryl nicotinate in aqueous solution was studied by the solubility method. The aqueous solubilities of the esters were about 10⁵ times increased by DM--CyD complexation. The phase-solubility diagram of the tocopheryl ester-DM--CyD systems showed a typicalA _p type, and the stability constants (K) of high-order complexes were estimated by analyzing the upward curvature of the diagrams. The solid complex of -tocopheryl nicotinate with DM--CyD in a molar ratio of 12 was prepared by the kneading method. The dissolution rate of the solid complex was much greater than that of the drug itself, and the rapidly dissolving form of -tocopheryl nicotinate, as an example, showed a markedly increased bioavailability (about 70-fold) after oral administration to fasted dogs.     

Band structure of even and ions of odd polyenes

The analysis of experimental data for singlet transitions (E _n) of even polyenes (I), cations (II) and anions (III) of odd polyenes show that for infinite chains E (I)/E (II)=E (I)/E (III) = 2:1. It is shown that the energy gap is equal for the three systems. In cases (II) and (III) there is a level (NBMO) in the gap which is vacant in (II) and occupied in (III). That is why the first optical transition in (II) and (III) depends on the semiwidth of the gap.     

Studies of the energy spectrum of α, ω- substituted polymethine chains. II. Polymethine chains with odd number of methine groups

The analysis of the experimental data for the energy of the longest wavelength optical transitions _n,opt of substituted polymethines X (CH)_2n+1 X shows that in the asymptotic case (n) _,opt does not tend to zero, as it follows from the empirically established correlations, but has a finite, non-zero value. It is shown that the energy gap of odd polymethines is the same as that of the even polymethines - the polyenes (E 2 eV). The substituents (X N, O, B) are responsible for the appearance of levels in the gap. These, depending on the substituent character, are vacant (X B) or occupied (X N, O). The transition from or to such a level determines the longest wavelength optical transition energy of polymethines.     

Effect of fusion conditions ofβ-polypropylene on the new crystallization

The new crystallization of -modification of polypropylene (-PP) was studied after melring as a function of the final temperature of fusion (T _F ). The new crystallization, thermal characteristics, polymorphic composition, and structure of recrystallized samples were highly influenced by theT _F level. As a function ofT _F , three characteristic regions were outlined: Region I below the melting point of -modification, region II between the melting points of - and -modifications, and region III above the melting point of -modification. In the vicinity of the melting points of both modifications, two narrow transition regions are observed where the crystallization and structural characteristics changed abruptly withT _F . AtT _F values in region I, recrystallization of -modification proceeded without any change in the modification. IfT _F fell in region II, the sample crystallized newly into -modification. The optically negative -ring-spherulites were replaced by positive microclusters of -modification and a marked structural memory effect was observed. In region III, the above characteristic became invariant withT _F (region of blank melt). These observations may be interpreted by the role of self nuclei.     

Die geruchsintensivsten Inhaltsstoffe des ostindischen Sandelholzöles

The most odour intensive constituents of east indian sandal wood oil are -santalol, -santalal and -santalene. This has been proved by a thorough GLC-investigation in combination with the sniffing technique of seven fractions of this highly priced essential oil, which have been obtained by TLC on silica-cellulose plates with simultaneous organoleptic evaluation. Using the headspace analysis these results could be confirmed and further the distribution of the main odour components was obtained in headspace at 37° and 80°.

Herrn Prof. DDr. h. c.K. Kratzl in dankbarer Verehrung mit den besten Wünschen zum 70. Geburtstag gewidmet.