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.     

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%).     

Triterpene Glycosides of Zygophyllum eichwaldii. II. Structure of Zygoeichwaloside I

Column chromatography of roots ofZygophyllum eichwaldiiC.A.M. (Zygophyllaceae) afforded the new glycoside zygoeichwaloside I. Acid hydrolysis, alkaline saponification, solvolysis, and ¹ H and ¹³ C NMR spectroscopies using COSY, TOCSY, ROESY, HSQC, and HMBC methods established its structure as the 28-O--D-glucopyranosyl ester of pomolic acid 3-O--D-2-O-sulfonylgalactopyranoside.     

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.     

Fluorodaturatin und Homofluorodaturatin—zwei neue β-Carbolinderivate in Samen von

In the transverse section of the seeds ofDatura stramonium L. var.stramonium a conspicuous sea-green fluorescence under UV-light (365 nm) can be observed. Thinlayer chromatography of a methanolic extract shows many blue and sea-green fluorescing substances, the main component being a polar, sea-green fluorescing compound. This substance is characteristic for all of the four varieties ofDatura stramonium L., and therefore of taxonomic interest. Isolation was tried by means of different chromatographic techniques. Combination of column chromatography and preparative thinlayer chromatography allowed the isolation of the main product, which was shown to consist of two substances (GF andGFa). Application of chemical and spectroscopic methods established the structure ofGF, named Fluorodaturatin, as 2,3,5,6-Tetrahydro-9-hydroxy-1H-pyrido-[1,2,3-l, m]--carboline-3-one. The second substanceGFa, called Homofluorodaturatin, was identified as analogue ofGF and the structure could be determined as 1,2,3,4,6,7-Hexahydro-10-hydroxyazepino-[1,2,3-l, m]--carboline-4-one.

Teil der DissertationI. Maier, Universität Wien, 1981; Auszugsweise vorgetragen bei der 2. Wissenschaftlichen Tagung der Österreichischen Pharmazeutischen Gesellschaft, 17. bis 19. Mai 1981, Graz.     

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.     

FLAVONOIDS OF Scutellaria ocellata AND S. nepetoides

The known flavonoids oroxylin A, wogonin, apigenin, 3,7,4'-trihydroxyflavone, cinaroside, baicalin, and wogonoside were isolated from the aerial part ofScutellaria ocellataJuz.; apigenin-7-O--D-glucuronide, norwogonoside, scutellarin, and the new flavoneglycoside nepetoside A, 5,8-dihydroxy-7-O--D-galacturonidopyranosylflavone, from the roots ofScutellaria nepetoidesM. Pop. The structure of the last is established using chemical transformations and spectral data.     

Exo-H- andendo-H-η4-pentamethylcyclopentadiene complexes of platinum

A mixture ofendo-H andexo-H isomers (1a and1b) of the (⁴-C₅Me₅H)PtCl₂ complex was prepared by the reaction of K₂PtCl₄ with C₅Me₅H in MeOH. The mixture of isomers reacts with CpTl in the presence of TiBF₄ to give a novel complex, [(⁴-C₅Me₅H)Pt(⁵-C₅H₅)]⁺BF₄ ^–, as a mixture ofendo-H- andexo-H-isomers (2a and2b). The data of¹H and¹³C NMR spectroscopy of the resulting complexes are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 514–517, March, 1994.     

Aminoamidines

Reactions ofN-aryl- andN-methyl-amidines and -amides of -amino acids with RPCl₂ afford 4-aryl(methyl)imino and 4-oxo-1,3,2-diazaphospholanes. 4-Phenylimino-1,3,2-diazaphosphorinane was obtained in a similar way by the interaction of N(1), N(2)-diphenyl--anilinoisobutyramidine with PhPCl₂.For communication 5 see ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1116–1121, June, 1993.     

Synthesis of 2′,3′-dideoxynucleosides from 5-alkoxymethyluracils

Summary A modified synthesis of protected 2,3-dideoxyribose5 starting fromL-glutamic acid (1) is described. Reaction of5 with silylated 5-hydroxymethyluracil7 a and 5-alkoxymethyluracils7 b–e in the presence of trimethylsilyl triflate afforded an anomeric mixture of 2,3-dideoxyuridine derivatives8 a–e and9 a–e. Deprotection with methanolic ammonia and separation by chromatography gave the corresponding nucleosides10 a–e and11 a–e. Treatment of9 b–e with tri(1H-1,2,4-triazol-1-yl)phosphine oxide and subsequent reaction of12 b–e with ammonia in dioxane afforded the cytosine derivatives13 b–e which on treatment with methanolic ammonia gave the corresponding 2,3-dideoxycytidine derivatives14 b–e and15 b–e. In contrast with the parent compounds, these alkoxymethyl derivatives had no appreciable activity against human immunodeficiency virus (HIV-1).

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Synthese von 2,3-Dideoxynucleosiden aus 5-Alkoxymethyluracilen

Zusammenfassung Ausgehend vonL-Glutaminsäure (1) wird eine modifizierte Synthese von geschützter 2,3-Dideoxyribose (5) beschrieben. Reaktion von5 mit silyliertem 5-Alkoxymethyluracilen7 b–e in Gegenwart von Trimethylsilyltriflat ergab anomere Mischungen der 2,3-Dideoxyuridinderivate8 a–e und9 a–e. Abspaltung der Schutzgruppe mit methanolischen Ammoniak und chromatographische Trennung ergab die entsprechenden Nucleoside10 a–e und11 a–e. Behandlung von9 b–e mit Tri(1H-1,2,4-triazol-1-yl)phosphinoxid und nachfolgende Reaktion von12 b–e mit Ammoniak in Dioxan ergab die Cytosinderivate13 b–e, welche nach Behandlung mit methanolischem Ammoniak die entsprechenden 2,3-Dideoxycytidinderivate14 b–e und15 b–e ergaben. Im Gegensatz zur Stammverbindung hatten diese Alkoxymethylderivate keine nennenswerte Wirksamkeit gegen den menschlichen Immunschwächevirus (HIV-1).

     

Reaction of aminals of conjugated unsaturated ω-dimethylaminoaldehydes with 1,2-, 1,3-, 1,4-, 1,5-, and 1,6-diketones

The condensation of aminals of -dimethylaminoacrolein and 5-dimethylaminopenta-2,4-dienal with cyclic and acyclic 1,2-, 1,3-, 1,4-, 1,5-, and 1,6-diketones was studied. A series of previously unknown bis(,-dimethylaminopolyenyl)diketones was synthesized; their structures were established by means of¹H and¹³C NMR spectroscopies. The electron absorption spectra were employed to study the mutual influence of -aminopolyene chromophores separated by two C=O groups.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1235–1241, July, 1993.     

Struktur/Geruchs-Beziehungen von mit β-Santalol verwandten Verbindungen:E-Homo-β-santalol undE-Dehydrohomo-β-santalol

Summary To study the structure/odour relationships of -santalol analogues two homologous -santalol derivatives5 and6 were synthesized. The key steps thereby were the -alkylation of the bicyclic starting ketones8 and14 accomplished by using more drastic conditions as usual. The odours of5 and6 are described in detail.

Auszugsweise vorgetragen am 19th International Symposium on Essential Oils and Other Substrates, 9. September 1988, Greifensee/Dübendorf, Schweiz     

A new approach to 6-deoxy-D-allofuranose- and 6-deoxy-L-talofuranose derivatives from 1,2:5,6-di-O-isopropylidene α-D-glucofuranose

3-O-Acetyl-1,2-O-isopropylidene--D-allofuranose (2 b) was prepared from 1,2:5,6-di-O-isopropylidene--D-allofuranose (1 b). Treatment of2 b with triphenylphosphine-diethyl azodicarboxylate afforded regio- and stereospecifically the 5,6-epoxy--D-allo derivative (3). The other diastereomeric compound, 5,6-epoxy-1,2-O-isopropylidene--L-talofuranose (6) was also prepared stereoselectively from2 b via the intermediates5 a and5 b. The epoxy sugars3 and6 were converted with lithium aluminum hydride to the corresponding 6-deoxy-1,2-O-isopropylidene--D-allofuranose (4 a) and --L-talofuranose (7 a) derivatives. Hydrolysis of4 a and7 a afforded 6-deoxy-D-allose and 6-deoxy-L-talose, respectively. The corresponding 3,5-di-O-acetyl- (4 b and7 b) and the 3,5-O-(tetraisopropyldisiloxane-1,3-diyl) derivatives (4 c and7 c) are also described. Selective removal of the isopropylidene group and subsequent acetylation offers a convenient route to prepare sugar derivatives containing furanose ring, like8 b, as a suitable precursor for nucleoside analogs.Herrn Prof. Dr.K. Komarek mit den besten Wünschen zum 60. Geburtstag gewidmet.     

Synthese von 1,1′-Biphenyl-3-carbonsäure-und 3,5-dicarbonsäurederivaten unter Verwendung von Ethoxymethylenmalononitril

Reaction of ethoxymethylenemalononitrile with ethyl 4-phenylacetoacetate leads to ethyl 1,1-biphenyl-6-amino-5-cyano-2-hydroxy-3-carboxylate (3). Acid or basic hydrolysis of the ester and cyano group of3 affords the new derivatives4,5 and6.7 a, b are obtained bySandmeyer-reaction of3. Basic hydrolysis of7 a gives the 3,5-dicarboxylic acid derivative8.

     

Strukturelle Abwandlungen anN-Acetylneuraminsäure, 4. Mitt. Transformationen am Diethyl-dithioketal desN-Acetylneuraminsäure-γ-lactons

Partial protection of diethyldithioketal ofN-acetylneuraminic acid--lactone using one or two equivalents oft-butyldimethylchlorosilane leads to the 9-O-silyletherderivative7 and the 8,9-bis-O-silylderivative5, resp. The reaction of1 as well as7 with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane (TIPSiCl₂) yields selectively the protected products4 and9. The 9,8,7,6-tetra-O-acetyl-N-acetylneuraminic acid--lactone derivative3 is formed by the oxidative desulfurazation of the peracteylated form of1 (i. e.2) by means ofNBS. By reaction of5 withTPPDEAD the 6,7-carbonato compound6 arises instead of the expected 6,7-epoxyderivative. The analogous carbonate8 is formed by treating7 with bisimidazolylcarbonate.

     

A spectrophotometric determination of the formation constants of the inclusion complexes ofα- andβ-cyclodextrins with the azonium and ammonium tautomers of methyl orange and methyl yellow

The color fading caused by the addition of-cyclodextrin or-cyclodextrin to an aqueous solution of a tautomeric mixture of methyl orange or methyl yellow is studied spectrophotometrically at pH 1.1 and 25.0°C. A model involving 1 : 1 stoichiometry has been used to analyze the spectrophotometric data. The addition of a cyclodextrin shifts the tautomeric mixture towards the side of the ammonium tautomer. An expression allowing the calculation of the tautomeric equilibrium constant of the inclusion complexes is derived. The formation constants of the inclusion complexes of the individual tautomers are determined. Both- and-cyclodextrins bind the ammonium tautomer stronger than the azonium tautomer. The inclusion complexes of-cyclodextrin are more stable than the corresponding ones of-cyclodextrin.     

Phenolic Components of Empetrum nigrum Extract and the Crystal Structure of One of Them

Four phenolic components are isolated from the CHCl ₃ extract ofEmpetrum nigrumL. Three of them are known from this plant. The fourth (6,8-dimethylpinocembrine) is isolated from crowberry for the first time. The previously proposed structure for 2'-methoxy-4'-hydroxy- ,-dihydrochalcone is confirmed by x-ray structure analysis     

Free and Sulfated Sterols of Two Far-East Leptasterias Starfish

NMR spectroscopy, capillary GLC, and GLC-MS are used to study the composition of free and sulfated sterols from the far-east starfishLeptasterias alaskensis asiatica(Fischer) andL. Fisheri(Djakonov). The total free sterols of both species are shown to have similar qualitative and quantitative compositions and contain mainly⁷ -sterols. Sterol sulfate fractions contain cholesterol sulfate as the main component but differ in the ratios of⁵ :⁰ :⁷ -sterol derivatives. Possible reasons for these differences are discussed. A new steroid, 3-hydroxycholest-5-en-7-one sulfate, was isolated.     

Preparation and stereoselectivity of 1,3-dipolar cycloaddition of C-glycosyl nitrones to N-arylmaleimides

Summary The cycloaddition of 3-hydroxyglycosyl-N-methylnitrone (1) to N-arylmaleimides gave thesyn isoxazolidines6, whereas 3-acetoxyglycosyl-N-methylnitrone (2) afforded theanti isoxazolidines8 and10. The formation of6 was rationalized by anexo attack, stereoelectronically preferred through the hydrogen bond between the pentose hydroxyl group and one of the carbonyl groups of N-arylmaleimide. The sterically preferredendo attack avoiding the repulsions between N-arylmaleimide and sugar moiety was proposed for addition of2. The structure and steric configuration of the products have been assigned on the basis of¹H- and¹³C-NMR spectroscopy, mainly by nuclear Overhauser effect difference spectroscopy. AM1 calculations of the nitrones and MM2 calculations of the adducts were performed.

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Darstellung und Stereoselektivität der 1,3-dipolaren Cycloaddition von C-Glycosyl-Nitronen an N-Arylmaleimiden

Zusammenfassung Die Cycloaddition von 3-Hydroxyglycosyl-N-methylnitron (1) an N-Arylmaleimide gab diesyn-Isoxazolidine6, mit 3-Acetoxyglycosyl-N-methylnitron (2) wurden hingegen dieanti-Isoxazolidine8 und10 erhalten. Die Bildung von6 wurde mit einemexo-Angriff erklärt, der stereoelektronisch wegen einer Wasserstoffbrückenbindung zwischen der Hydroxylgruppe der Pentose und einer Carbonylgruppe des N-Arylmaleimides bevorzugt wird. Für die Addition von2 wurde ein sterisch bevorzugterendo-Angriff vorgeschlagen, da dabei ungünstige Wechselwirkungen zwischen der N-Arylmaleimid- und der Zuckereinheit vermieden werden. Die Struktur und Stereochemie der Produkte wurde mittels¹H- und¹³C-NMR unter Verwendung von NOE-Differenzmessungen ermittelt. Es wurden auch AM1-Rechnungen für die Nitrone und MM2-Rechnungen für die Addukte durchgeführt.

     

Chain entanglement,mechanical properties and drawability of poly(lactide)

The observed brittle fracture behavior of amorphous polylactides seems to be contradicted by the low value ofC =2 determined for poly(L-lactide) by Flory and coworkers. Such very flexible polymer chains deform by shear yielding, and fracture in a ductile manner. In this study,C was estimated in a number of ways, resulting in much higher values ofC =11.7 andC =9.1 for poly(L-lactide) and L- and D-lactide copolymers, respectively. These high values ofC and the low entanglement density account for the brittle fracture behavior of amorphous poly(lactide), as well as for the maximum attainable draw ratios of poly(L-lactide) networks and melt spun fibers. Bulk polymerized poly(L-lactide) networks, where crystallization during polymerization impedes severe entangling, could be hot-drawn most effectively to draw ratios of 8–16, resulting in very strong materials with tensile strengths of 550–805 MPa. By comparison, amorphous, non-crystallizable L/D lactide networks, which do not crystallize during polymerization, could be drawn less, to =7. These materials with strengths up to 460 MPa could, nevertheless, be oriented much more effectively than linear, amorphous L/D lactide copolymers.