bluuebunny/crossref_metadata_2025_split huggingface dataset:
Totalsynthese von natülichem α‐Tocopherol. 5. Mitteilung. Asymmetrische Alkylierung und asymmetrische Epoxidierung als Methoden zur Einführung der (R)‐Konfiguration an C(2) des Chroman‐Systems
Authors: Hübscher Josef , Barrier Richard 
Published: December 2004

Total Synthesis of Naturally Occurring α‐Tocopherol. Asymmetric Alkylation and Asymmetric Epoxidation as Means to Introduce (R)‐Configuration at C(2) of the Chroman MoietyBased on the reductive, stereospecific ring closure of (2R,4′R,8′R)‐α‐Tocophcrylquinone′ or corresponding analogues with a short, functionalized side chain (B, Scheme 1) to 1 resp. the chroman system of 1 (C), two different approaches for the introduction of the required tertiary methyl‐substituted alcohol structure in the side chain of the aromatic precursors (A, Scheme 1) were developed. The first approach uses asymmetric alkylation in three different versions featuring (a) diastereoselective steering with chiral auxiliaries I‐IV (Scheme 2) attached as esters to a‐keto acids, (b) intermediate transfer of chirality in an ester enolate (from 18, Scheme 4) derived from an optically active α‐hydroxy acid, (c) enantioselective alkylation of phytenal (20) and subsequent ring closure with chirality transfer (Schemes 5–7). The second approach is based on the asymmetric epoxidation of β‐metallylalcohol (Sharpless epoxidation), the corresponding epoxyalcohol being converted in situ to the (S)‐or (R)‐chlorodiol (S)‐and (R)‐29, respectively, for isolation (Schemes 8 and 9). Nucleophilic epoxide opening with a (3R 7R)‐3,7,11‐trimethyldodecyl (C15**) and an ArCH2 unit in appropriate sequence is used to assemble the C‐framework of the target molecule via corresponding epoxide intermediates from either chlorodiol. Combined with the use of the methoxymethyl‐ether function for protection of the hydroquinone system, the epoxide approach provides a short route to 1 (Scheme 10).
Die Synthese des Labdanditerpenes Erigerol und analoger Verbindungen
Authors: Kienzle Frank , Stadlwieser Josef , Rank Werner , Schonholzer Peter 
Published: December 2004

The Synthesis of the Labdane Diterpenoid Erigerol and of Analogous CompoundsThe synthesis of Erigerol (1) and of analogous compounds in a 23‐step sequence is described. The various difficulties of the synthesis and several blind alleys that have been followed are discussed.
Synthesis and Properties of a New Dihydroflavin: Reduction of a Flavinium Salt by Borocyanohydride
Authors: Szczesna Violetta , Müller Franz , Vervoort Jacques 
Published: December 2004

AbstractReduction of 6 by borocyanohydride yielded the new dihydroflavin 7. The intermediate product 8 could only be observed in solution by 1H‐NMR. The chemical and physical properties of 7 are reported. UV/VIS, 1H‐ and 13C‐NMR, and luminescence techniques were used.
Regio‐, Diastereo‐, and Enantioselective Synthesis of Vicinal Diols via α‐Silyl Ketones
Authors: Enders Dieter , Nakai Shiro 
Published: December 2004

AbstractA new versatile and efficient regio‐, diastereo‐, and enantioselective synthesis of vicinal diols s‐trans‐4, s‐trans‐5, and s‐cis‐4 is described. Symmetrical ketones are converted into their SAMP‐or RAMP‐hydrazones which are then silylated with (isopropyloxy)dimethylsilyl chloride, followed by ozonolysis to afford the α‐silyl ketones (R)‐2 of high enantiomeric purity (ee 90– ≥ 98%). On the other hand, methyl ketones, after conversion into the corresponding (−)–(S)‐1‐amino‐2‐(methoxymethyl) pyrrolidine (SAMP) hydrazones, are silylated and then alkylated with RI to afford unsymmetrical α‐silyl ketones (S)‐3 of high enantiomeric purity (ee 90‐ ≥ 98%). The reduction of the above obtained α‐silyl ketones with L‐Selectride, followed by oxidative cleavage of the CSi bond gives rise to s‐trans‐4, s‐trans‐5, and s‐cis‐4 with high diastereoselectivity (de 95‐ ≥ 98%) and without racemization (ee ≥ 90– ≥ 98%).
Probing the Anomeric Effect in OCN Systems Theory vs. Experiment: MO‐ab initio Calculations and a Structural‐Statistical Analysis
Authors: Senderowitz Hanoch , Aped Pinchas , Fuchs Benzion 
Published: December 2004

AbstractA combined computational (MO ab initio) and structural‐statistical study of molecules containing the OCN moiety is presented. Aminomethanol, the simplest member of this series, was computed using GAUSSIAN‐82 with the 3‐21G and 6‐31G* basis sets and with complete geometry optimization, as well as with MP3//6‐31G*. A set of carefully selected molecules containing the OCN unit was retrieved from the Cambridge Structural Database (CSD), and its structural parameters were analyzed according to an established procedure. Comparison between experimental and computational data was thus made possible. Results are consistent with the co‐existence of two unequal anomeric effects in this system: a strong nN‐σ*CO anomeric interaction, and a weak nπO‐σ*CN one. The ability of the two basis sets to reproduce the energies and structural characteristics of the stereoelectronic effects is assessed, including the significance of using polarization functions and the inclusion of correlation energy.
Asymmetric Diels‐Alder Cycloadditions with C2‐Symmetrical Chiral Carbamoylnitroso Dienophiles
Authors: Defoin Albert , Brouillard‐Poichet Agnès , Streith Jacques 
Published: December 2004

AbstractThe C2‐symmetrical chiral pyrrolidines 2 and 3 are of opposite helicity. The corresponding N‐acylnitroso dienophiles 6 and 7 react in good yield with cyclohexadiene, leading thereby with excellent diastereoisomeric excess to the expected Diels‐Alder cycloadducts (see Scheme). The [2.2.2] bicyclic moieties of the major diastereoisomers 9 and 11 proved to be of opposite configuration, as expected. Their configuration is best explained by assuming the acylnitroso dienophile to be in the s‐cis conformation in the transition state, the approach of the diene being endo (see Fig.).
Ammodoremin, an Epimeric Mixture of Prenylated Chromandiones from Ammoniacum
Authors: Appendino Giovanni , Nano Gian Mario , Viterbo Davide , De Munno Giovanni , Cisero Marco , Palmisano Giovanni , Aragno Manuela 
Published: December 2004

AbstractFrom the gun resin Ammoniacum, an epimeric mixture 2a/3a of highly functionalized prenylated chromandiones was isolated. Their structure was established by spectral data and single‐crystal X‐ray analysis. The compounds were isolated as acetates 2b/3b, and these derivatives showed in vivo haemorrhagic activity.
Syntheses and Crystal Structures of 4,5‐Dihydro‐2‐(2′‐hydroxyphenyl)oxazole‐Containing Metal Complexes
Authors: Bolm Carsten , Weickhardt Konrad , Zehnder Margareta , Glasmacher Dorothea 
Published: December 2004

AbstractThe synthesis of the complexes 3 of various metals ligated to chiral 4,5‐dihydro‐2‐(2′‐oxidophenyl‐ϰO)oxazoles‐ϰN is described (Scheme). Three of them, i.e. 3a, 3e, and 3f containing CuII, ZnII and NiII, respectively, were analyzed by X‐ray diffraction studies. A series of CuII complexes (6a–d) with differently substituted dihydrooxazoles have been synthesized.
Synthesis and X‐Ray Crystal Structure of an Optically Pure Tripodal C3‐Symmetric Tritertiary Phosphine Bearing Chirality on Phosphorus
Authors: Ward Thomas R. , Venanzi Luigi M. , Albinati Alberto , Lianza Francesca , Gerfin Tobias , Gramlich Volker , Tombo Gerardo M. Ramos 
Published: December 2004

AbstractThe preparation of the optically pure tritertiary phosphine (RRR)‐MeSi(CH2P(t‐Bu)Ph)3 (2) is reported. The route followed involves deprotonation of optically pure (R)‐P(BH3)Me(t‐Bu)PH (2) the reaction of the resulting carbanion with MeSiCl3, followed by removal with morpholine of the BH3‐protecting groups from the triertiary phosphine‐borane 3. The latter's X‐ray crystal structure and that of [Rh(NBD)((RRR)‐1]TOf)(4), are also rported. Furthermore, it is shown that the separation of the racemic phosphine‐borane 2 can be conveniently carried out using medium‐pressure liquid chromatgrapy with cellulose‐riacetate as a chiral stationary phase.
Ringerweiterung von 1,2‐Thiazol‐3(2H)‐on‐1,1‐dioxiden und 3‐Amino‐2H‐azirinen zu 4H‐1,2,5‐Thiadiazocin‐6‐on‐1,1‐dioxiden
Authors: Rahm Annette , Linden Anthony , Vincent Beverly R. , Heimgartner Heinz , Mühlstädt Manfred , Schulze Bärbel 
Published: December 2004

Ring Enlargement of 1,2‐Thiazol‐3(2H)‐one‐1,1‐dioxides and 3‐Amino‐2H‐azirines to 4H‐1,2,5‐Thiadiazocin‐6‐one‐1,1‐dioxidesReaction of 3‐amino‐2H‐azirines 2 with the 1,1‐dioxides 4 and 7 of 1,2‐thiazol‐3(2H)‐ones and 1,2‐thiazoli‐din‐3‐ones, respectively, in i‐PrOH at room temperature leads to 4H‐1,2,5‐thiadiazocin‐6(5H)‐one‐1,1‐dioxides 5 (Scheme 2, Table) and the corresponding 7,8‐dihydro derivatives 8 (Scheme 4), respectively. The structure of some of the new 8‐membered heterocycles as well as the structure of the minor by‐product 6 (Scheme 3) have been established by X‐ray crystallography (Chapt. 4). The proposed reaction mechanism for the ring expansion to 5 and 8 (Scheme 2) is in accordance with previously published results of reactions of 2 and NH‐acidic heterocycles and is further supported by the results of the reaction of 4a and the (1‐15N)‐labelled aminoazirine 2a*.
Structure and reactivity of xanthocorrinoids. Part V. Formation of trans‐diol derivatives of 5,6‐dihydrocobyrinic acid from xanthocorrinoids under acidic conditions
Authors: Holxe Gerhard , Jenny Titus A. , Nesvadba Petr , Gossauer Albert , Ernst Ludger , Keller Walter , Kratky Christoph 
Published: December 2004

AbstractOn treatment with H2SO4/MeOH, epimerization of hexamethyl cis‐5,6‐dihydroxycobyrinate c,8‐lactam (3) takes place quantitatively at C(6), yielding the corresponding trans‐diol 4. The corresponding lactone 7, whose structure has been established by X‐ray analysis, is obtained from xanthocorrinoids 5 and 6 under similar conditions.
Reactions of Sulfinylated Radicals. Stereoselectivity in Six‐Membered Rings
Authors: Rehaud Philippe 
Published: December 2004

AbstractThe allylation and deuteration of six‐membered cyclic sulfinylated radicals were investigated. For this purpose, radicals with the predefined conformations I and II were generated from 2‐(phenylselenenyl)thiacyclo‐hexane‐1‐oxide derivatives 7–10 (Scheme). Steric effects were insufficient to account for all the observed selectivities. The participation of stereoelectronic effects are envisaged to explain the stereoselective axial deuteration of type‐II radicals.
Cuprous complexes and dioxygen. Part 11. Concomitant one‐ and two‐electron reduction of O2 by the Cu ion
Authors: Mi Li , Zuberbühler Andreas D. 
Published: December 2004

AbstractThe autoxidation of CuI in aqueous MeCN has been studied using a Clark oxygen electrode in the presence and absence of Cu11. The reaction is inhibited by Cu11 in the pH range of 0.5 to 5.0, reaching a lower limiting value at the highest concentrations. The reaction order changes from 1 to 2 with respect to CuI under the influence of Cu2+ ion. Detailed kinetics analysis of a total of 275 measurements has shown that an unstable primary adduct CuO+2 decomoses to give .O or HO, depnding on pH, and also reacts directly with a second Cu+ ion, avoiding one‐electrton reduction of O2 by this path. Reaction of HO is faster with CuI than with Cu11 by a factor of 20, and single‐electron transfer within CuO+2 to Cu2+ and .O predominates over reaction with a second copper ion for [CuItot] < 2. 10−3M in the absence of Cu2+. The most likely value for the reaction of .O with CuI is 5.3 · 108 M−1S−1, but even this high rate constant is at the limit of significance. All secondary reactions followinfg the initial formation of CuO+2 are shown to be very fast, a fact that should be properly considered in the discussion of mechanisms of copper‐catalyzed oxidations and oxygenations.
A Reduction Catalyst Powered by Its Own 10‐Electron Battery: Synthesis and properties of a pentaviologen‐linked corrinatocobalt complex
Authors: Steiger Beat , Walder Lorenz 
Published: December 2004

AbstractThe synthesis and properties of the molecular reduction device 7b (CoII–V) consisting of a reduction catalyst (a derivative of vitamin B12, CoII) and a covalently linked 10‐electron reservoir (five viologen units, V++) is described. The five viologen subunits were introduced at C(2) and C(3) of the side chains c and g and b, e and f, respectively, of an appropriate derivative of heptamethyl cob(III)yrinate by N‐alkylation of 1‐methyl‐4,4′‐bipyridinium iodide (see Scheme). The pentaviologen‐linked corrinatocobalt(II) complex 7b behaves as a molecular electron trap with respect to the CoIII/CoII redox couple. The phenomenon is related to the structural and thermodynamic relation of the corrin and viologen subunits in 7b, i.e. the relative redoc energies and the spherical inner‐outer arrangement of the types of redox systems. When completely reduced to CoI–V, 7b exhibits multiple reductive elimination of trans‐1,2‐dibromocyclohexane to cyclohexene under concomitant oxidation to CoII–V. Rate measurements indicate that the reduction occurs via CoI which is regenerated by intramolecular electron transfer from the periphery of the molecule, i.e. by V0 and V++.
[(1,3‐Dioxolan‐2‐yliden)methyl]phosphonate und ‐phosphinate als (einfache) Synthone in der Heterocyclensynthese
Authors: Neidlein Richard , Eichinger Thomas 
Published: December 2004

[(1,3‐Dioxolan‐2‐ylidene)methyl]phosphonates and ‐phosphinates as [simple] Synthons in Heterocyclic SynthesisThe readily available [(1,3‐dioxolane‐2‐ylidene)methyl]phosphonates and ‐phosphinates 2a–f (Scheme 1) can be transformed with amines to aliphatic ketene N,O‐and N,N‐acetales (see Scheme 2, 2a → 3–7). Alkanediamines yield with 2a–f the imidazolidines 8a–f and the hexahydropyrimidines 9a–d (Scheme 3). the oxazolidine derivatives 10a–e and the thiazolidine 11 are accessible under special reaction conditions starting from 2a, b (Scheme 4). Hydrazines react with the CN‐group‐containing ketene O,O‐acetals 2a–c to the pyrazoles 12a–g, whereof 12a, d, e can be cyclized to pyrazolo[1,5‐a]pyrimidines 13a–d (Scheme 5). Amidines as starting materials transform 2a–c in an analogous way to the pyrimidine derivatives 14a–c (Scheme 6).
Thermodynamic Enantioface‐Binding Selectivities of Monosubstituted Alkenes to a Highly Discriminating Chiral Transition ‐Metal Lewis Acid; equilibration of diastereoisomeric (cyclopentadienyl)(alkene)(nitrosyl)(triphenylphosphine)rhenium complexes ([Re(η5–C5H5)(CH2 = CHR)(NO) (PPh3)]+BF)
Authors: Peng Tang‐Sheng , Arif Atta M. , Gladysz John A. 
Published: December 2004

AbstractReactions of monosubstituted alkenes RCH = CH2 and [Re(η5–C5H5)(CH2Cl2) (NO)(PPh3)]+BF give complexes ([Re(η5–C5H5))(CH2CHR)(NO) (PPh3)]+BF (1a–g) in 63–99% yields as mixtures of (RS,SR)‐ and (RR,SS)‐diastereoisomers (1a (R = Me), 66:34; 1b (R = Pr), 63:37; 1c (R = PhCH2), 70:30; 1d (R = Ph), 75:25; 1e (R = i‐Pr), 64:36; 1f (R = t‐Bu), 84:16; 1g (R = Me3Si), 69:31; Scheme 2). These differ in the CC enantioface bound to the chiral Re fragment. In most cases, the analogous reactions of RCHCH2 and [Re(η5–C5H5) (C6H5Cl)(NO)(PPh3)]+ BF give comparable results. When 1a–e, g are heated in PhCl at 95–100°, equilibration to 96:4, 97:3, 97:3, 90:10, > 99:< 1, and > 99:< 1 (RS,SR)/(RR,SS) mixtures occurs (79–99% recoveries; Tables 1 and 2). Thus, thermodynamic enantioface‐binding selectivities are much higher than kinetic binding selectivities. This phenomenon is analyzed in detail. A crystal structure of (RS,SR)‐1e (monoclinic, P21/c, a = 10.256(1) Å. b = 17.191(1) Å, c = 16.191(1) Å, β = 101.04(1)°, Z = 4) shows that the Re–C(1)–C(2) plane (see Fig.2) is nearly coincident with the Re–P bond (angle 15°), and that the i‐Pr group is ‘syn’ to the nitrosyl ligand.
O‐Insertion into Nonactivated CH Bonds: The first observation of O2 cleavage by a P‐450 enzyme model in the presence of a thiolate ligand
Authors: Patzelt Heiko , Woggon Wolf‐Dietrich 
Published: December 2004

AbstractOn reaction with ‘O’‐donors or O2, the synthetic P‐450 analogue 2 undergoes O‐insertion at a nonactivated CH bond of the covalently bound substrate. The mechanism of O‐insertion with O2 most likely involves homolytic cleavage of the OO bond followed by O‐insertion via radical recombination.
Eine neue einfache Synthese spirocyclischer 1H‐Chinolin‐Derivate
Authors: Walter Harald , Sauter Hanspeter , Winkler Tammo 
Published: December 2004

A New and Simple Method for the Synthesis of Spirocyclic la‐QuinolinesThe reaction of anilines with (+)‐(R)‐pulegone in toluene at temperatures between 125 and 150° with 4‐toluenesulfonic acid or I2 as catalysts leads to diastereoisomeric mixtures of spiro[cyclohexane‐1,2′(1′H)‐quinoline] derivatives (see 1–4, Scheme 1; Table). The diastereoisomers are separated by column chromatography, and the structure of the single isomers is determined by NMR‐spectroscopic methods. A reaction mechanism proceeding via several 6π‐electrocyclic rearrangements and H‐shifts is proposed for the formation of 1H‐quinolines 1–4 (Scheme 2). This mechanism is in accordance with the results of the reaction of 2‐isopropenylaniline with 3‐methylcyclohexanone which leads to a stereoisomeric mixture of 3,4′‐dimethylspiro[cyclohexane‐1,2′(1H)‐quinolines] (Scheme 3).
Warum Pentose‐ und nicht Hexose‐Nucleinsäuren??. Teil II. Oligonucleotide aus 2′,3′‐Dideoxy‐β‐D‐glucopyranosyl‐Bausteinen (‘Homo‐DNS’): Herstellung.
Authors: Böhringer Markus , Roth Hans‐JÖRg , Hunziker Jürg , Göbel Michael , Krishnan Ravichandran , Giger Alfred , Schweizer Bernd , Schreiber Jakob , Leumann Christian , Eschenmoser Albert 
Published: December 2004

Why Pentose and Not Hexose Nucleic Acids? Part II.
Preparation of Oligonucleotides Containing 2′,3′‐Dideoxy‐β‐D‐glucopyranosyl Building Blocks(7)
This paper describes the preparation of the 2′,3′‐dideoxy‐β‐D‐glucopyranosyl‐( = 2′,3′‐dideoxy‐β‐D‐erythro‐hexopyranosyl)‐derived nucleosides of the five bases adenine, cytosine, guanine, thymine, and uracil ( = ‘homo‐de‐oxyribonucleosides’) as well as the synthesis of oligonucleotides derived from them. The methods used for both nucleoside and oligonucleotide synthesis closely follow the known methods of synthesis in the corresponding series of natural 2′‐deoxyribonucleosides and oligonucleotides. The efficient methods of automated DNA synthesis proved to be fully applicable to the synthesis of homo‐DNA oligonucleotides, the only change necessary for achieving satisfactory coupling yields being a slight lengthening of the coupling time. Homo‐DNA oligonucleotides with chain lengths of up to twelve nucleoside units were assembled on solid support either manually or on a commercial DNA synthesizer in scales of 0.4 μmol to as much as 200 μmol and were purified by either reversed‐phase or ion‐exchange HPLC to single‐peak purity according to both chromatographic systems (estimated purity > 95%). The choice of the specific base sequences to be synthesized was determined primarily by the constitutional problems of base pairing that emerged from experimental observations made in the course of systematic studies of the pairing properties of homo‐DNA oligonucleotides. About 100 homo‐DNA sequences were prepared for this purpose. Their pairing properties will be described in Part III of this series; the present paper is restricted to the characterization of the purity and constitutional integrity of a few selected (single‐stranded) oligonucleotides by 1H‐, 31P‐, and 13C‐NMR spectroscopy as well as by FAB and time‐of‐flight mass spectroscopy.The English Footnotes to Schemes 1–9, Fig. 1–12, and Table 1 provide an extension of this summary.
3‐Deaza‐2′‐deoxyadenosine: Synthesis via 4‐(methylthio)‐1H‐imidazo[4,5‐c]pyridine 2′‐deoxyribonucleosides and properties of oligonucleotides
Authors: Seela Frank , Grein Thomas , Samnick Samuel 
Published: December 2004

AbstractThe synthesis of 4‐(methylthio)‐1H‐imidazo[4,5‐c]pyridine 2′‐deoxy‐β‐D‐ribonucleosides 2 and 9 and the conversion of the N1‐isomer 2 into the 2′,3′‐didehydro‐2′,3′‐dideoxyribonucleoside 3a or (via 7) 3‐deaza‐2′‐deoxyadenosine (1) is described. Phosphonate building blocks of 1 were employed in solid‐phase synthesis of self‐complementary base‐modified oligonucleotides. Their properties were studied with regard to duplex stability and hydrolysis by the restriction enzyme Eco RI.
A Ring‐Enlargement Reaction Yielding 1,2,5‐Benzothiadiazonin‐6‐one 1,1‐Dioxides
Authors: Orahovats Alexander S. , Linden Anthony , Heimgartner Heinz 
Published: December 2004

AbstractAt room temperature or under reflux in MeCN, 3‐amino‐2H‐azirines 2 and 3,4‐dihydro‐2H‐1,2‐benzothiazin‐3‐one 1,1‐dioxide (4) give 1,2,5‐benzothiadiazonin‐6‐one 1,1‐dioxides5 in fair‐to‐good yield (Scheme 2). The structure of this novel type of heterocyclic compounds has been established by X‐ray crystallography of 5a (Fig.). A ring expansion via a zwitterionic intermediate of type A' is proposed as the reaction mechanism of the formation of 5.
Ruthenium‐Catalyzed Enantioselective Hydrogenation of 1,3‐O‐Disubstituted 1,3‐Dihydroxypropan‐2‐ones
Authors: Cesarotti Edoardo , Antognazza Patrizia , Mauri Angela , Pallavicini Marco , Villa Luigi 
Published: December 2004

AbstractOptically active 1,3‐O‐disubstituted glycerols were obtained by enantioselective homogeneous hydrogenation of the corresponding 1,3‐O‐disubstituted 1,3‐dihydroxypropan‐2‐ones with different RuII‐binap complexes. The highest enantioselectivities were obtained with dimeric chloro‐ruthenium complexes on the substrates bearing bulky trityloxy groups.
A New Asymmetric Synthesis of Tricarbonylchromium Complexes of ortho‐Substituted Benzaldehydes. Preliminary communication
Authors: Kündig E. Peter , Liu Ronggang , Ripa Alberto 
Published: December 2004

Abstractortho‐Substituted [Cr(CO)3(benzaldehyde)] complexes are obtained via nucleophilic addition of alkyl‐ and aryllithium reagents to a [Cr(CO)3(phenylmethaneimine)] complex followed by endo‐hydride abstraction with triphenylmethyl cation. This sequence, when carried out with a [Cr(CO)3(benzaldehyde SAMP hydrazone)] complex affords substituted derivatives (Me, Bu, Ph, vinyl) with high (⩾97%) diastereoselectivity and, after hydrolysis, ortho‐ substituted [Cr(CO)3(benzaldehyde)] ((S)‐1) complexes of high enantiomeric purity.
New Monoterpene‐Substituted Dihydrochalcones from Piper aduncum
Authors: Orjala Jimmy , Wright Anthony D. , Erdelmeier Clemens A. J. , Sticher Otto , Rali Topul 
Published: December 2004

AbstractFive New unusual monoterpene‐substituted dihydrochalcones, the adunctins A–E (1″S)‐1‐{2′‐hydroxy‐4′‐methoxy‐6′‐[4″‐methyl‐1″‐(1‴‐methylethyl)cyclohex‐3″ ‐en‐1″ ‐yloxy]phenyl}‐3‐phenylpropan‐1‐one (1), (5aR*,8R*,9aR*)‐3‐phenyl‐1‐[5′,8′,9′,9′a‐tetrahydro‐3′‐hydroxy‐1′‐methoxy‐8′‐(1″‐methylethyl)‐5′‐a‐methyldibenzo‐[b,d]furan‐4′‐yl]propan‐1‐one (2), (2′R*,4″S*)‐1‐{6′‐hydroxy‐4′‐methoxy‐4″‐(1‴‐methylethyl)spiro[benzo[b]‐furan‐2′(3′H),1″ ‐cyclohex‐2″ ‐en]‐7′‐yl}‐3‐phenylpropan‐1‐one (3), (2′R*,4″R*)‐1‐{6′‐hydroxy‐4′‐methylethyl‐4″‐(1‴‐methylethyl)spiro[benzo[b]furan‐2′(3′H),1″‐cyclohex‐2″‐en]‐7′‐yl}‐3‐phenypropan‐1‐one (4), and (5′aR*,6′S*, 9′R*,9′aS*)‐1‐[5′a,6′,7′,8′,9′a‐hexahydro‐3′,6′‐methoxy‐6′‐methyl‐9′‐(1″‐methylethyl)dibenzo[b,d]‐furan‐4′‐yl]‐3‐phenylpropan‐1‐one (5) were isolated from the leaves of Piper aduncum (Piperaceae) by preparative liquid chromatography. In addition, (−)‐methyllindaretin (6), trans‐phytol, and α‐tocopherol ( = vitamin E) were also isolated and identified. The structures were elucidated by spectroscopic methods, including 1D‐ and 2D‐NMR spectroscopy as well as single‐crystal X‐ray diffraction analysis. The antibacterial and cytotoxic potentials of the isolates were also investigated.
Application of Electrospray Mass Spectrometry for Characterizing Supramolecular Coordination Complexes
Authors: Hopfgartner Gérara , Henion Jack D. , Piguet Claude , Williams Alan F. 
Published: December 2004

AbstractThe Electrospray Mass Spectrometry (ES‐MS) of eight different supramolecular complexes shows that the molecular peaks of the desolvated multiply charged cations can be recorded more easily than by Fast‐Atom‐Bom‐bardment Mass Spectrometry (FAB‐MS) measurements of similar compound. The preliminary application of the ES‐MS technique to self‐assembled helical complexes obtained from ligands L3 to L8 with various metal ions (Cu, Co, Eu, Tb) indicates that ES mass spectra qualitatively reflect the species present MeCN solution.