bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Spirostaphylotrichins from Staphylotrichum coccosporum
Authors: Sandmeier Peter , Tamm Christoph 
Published: December 2004

AbstractThe isolation and structure elucidation of the new spirostaphylotrichins B (2), C and D (3/4), F (5), Q (6), and R (7) are described. Compounds 2 and 3 are artefacts formed during the isolation of the metabolites from the cultures. The absolute configuration of spirostaphylotrichin A (1) has been determined by CD spectroscopy.
Stereoselektive Synthese von 3,5‐disubstituierten Octahydroindolizinen
Authors: Vavrecka Mojmir , Hesse Manfred 
Published: December 2004

AbstractA Stereoselective Synthesis of 3,5‐Disubstituted OctahydroindolizinesOn catalytic hydrogenation, methyl 6‐nitro‐9‐oxodecanoate (1) underwent cyclization to 2 which, after hydrolysis, gave the bicyclic product 4. By another series of reactions, 2 was transformed to methyl 3‐methyloctahydroindolizine‐5‐carboxylate (7), Conversions of 7a to its C(5)‐epimer 7b and vice versa were accomplished and the configurations of 7a and 7b determined. Finally, 7b was reduced in three steps to 11 (overall yield from 1, 24%), which is an analog of several natural products.
Modelling the Metabolic Epimerization of Anti‐inflammatory 2‐Arylpropanoyl‐coenzyme‐A Conjugates: Solvent effects on the 1H/2H exchange in S‐[2‐(dimethylamino)ethyl] 2‐phenylpropanethioate
Authors: Mayer Joachim M. , Young Malcolm , Testa Bernard , Etter Jean‐Claude 
Published: December 2004

AbstractThe 1H/2H exchange at the methine position of S‐[2‐(dimethylamino)ethyl] 2‐phenylpropanethioate (DEPP) in solvent/D2O mixtures was taken as a model reaction for the metabolic epimerization of 2‐arylpropanoyl‐coenzyme‐A thioesters and was monitored by 1H‐NMR spectroscopy at 37°. The solvents used were (D6)acetone, (D3)acetonitrile, (D6)dimethylsulfoxide, and (D5)pyridine. In the investigated range of D2O percentage (10–50%), the exchange reaction was found to increase linearily with D2O content and with the basicity of the organic solvent, the fastest rates being close to 0.09 h−1 (t½ ca. 8 h). These rates are slower than those observed in vivo for the configurational inversion of profens, and they are elicited in totally unphysiological concentrations of bases. The hypothesis thus formulated is that the metabolic epimerization of 2‐arylpropanoyl‐coenzyme‐A thioesters cannot occur nonenzymatically.
Synthesis of an N‐Acetylated Heparin Pentasaccharide and its anticoagulant activity in comparison with the heparin pentasaccharide with high anti‐factor‐Xa activity
Authors: Peter Wessel Hans , Labler Ludvik , Tschopp Thomas B. 
Published: December 2004

AbstractThe synthesis of tri‐N‐acetylated heparin pentasaccharide 2 is described. It was assembled from five suitably blocked monosaccharide units (3–7). Glucuronic‐acid building block 4 was prepared from glucose by direct Jones oxidation of the 6‐O‐trityl derivative 18. The resulting acid 16 was esterified to 17 in large mounts using methyl chloroformate/base. Trimethylsilyl bromide proved to be an excellent reagent for the hydrolysis of a prop‐1‐enyl glycoside (19 →21). The pentasaccharide 29 was obtained by a [2 + 2] + 1 synthesis, the glycosylation reactions furnished good to very good yields. The identity of protected oligosaccharides was confirmed by 1H‐NMR spectroscopy. Sequential deblocking of the pentasaccharide, O‐sulfation, and N‐acetylation gave 2 which was shown to exhibit ca. 600 times lower anticoagulant activity than pentasaccharide 1.
Separation of enantiomeric algal pheromones and related hydrocarbons by gas‐liquid Chromatography on Modified Cyclodextrins as Chiral Stationary Phases. Biosynthetic relevance of racemic by‐products
Authors: Boland Wilhelm , König Wilfried A. , Krebber Ralph , Müller Dieter G. 
Published: December 2004

AbstractThe separation of the enantiomers of the olefinic hydrocarbons multifidene 3 and aucantene 5 from the pheromone blend of the two seaweeds Cutleria multifida and Chorda tomentosa is achieved by gas chromatography on modified cyclodextrins as chiral stationary phases. The method is also applicable for the separation of enantiomeric alkyl‐, alkenyl‐ or alkynyl‐substituted cyclooctadienes and cyclopentenes. A plausible rational is presented for the biosynthesis of racemic by‐products of algal pheromone blends.
Nucleotides part XXX Chemical synthesis of adenylyl‐(2′ → 5′)‐adenylyl‐(2′ → 5′)‐8‐azidoadenosine, and activation and photoaffinity labelling of RNase L by [32P]p5′A2′p5′A2′p5′N38A
Authors: Charubala Ramamurthy , Pfleiderer Wolfgang , Sobol Robert W. , Wu Li Shi , Suhadolnik Robert J. 
Published: December 2004

AbstractThe chemical synthesis of adenylyl‐(2′–5′)‐adenylyl‐(2′–5′)‐8‐azidoadenosine (15) was performed by the phosphotriester approach. Enzymatic phosphorylation of 15 by [γ‐32P]ATP led to the corresponding labelled 5′‐monophosphate 16. Photoinsertion of 16 took place on UV irradiation by covalent cross linking to a protein of Mr 80 K known to be RNase L. Radiobinding and core‐cellulose assays as well as photoaffinity labelling experiments with 16 are described.
Application of the gold(I)‐Catalyzed aldol reaction to a stereoselective synthesis of (2S, 3R, 4R, 6E)‐3‐Hydroxy‐4‐methyl‐2‐(methylamino)oct‐6‐enoic Acid ( = MeBmt), Cyclosporin's unusual amino acid
Authors: Togni Antonio , Pastor Stephen D. , Rihs Grety 
Published: December 2004

AbstractThe title compound 8 was prepared in three steps starting from the optically pure aldehyde (2R, 4E)‐2‐methyl‐hex‐4‐enal (3), thus constituting the shortest synthetic approach reported. Two of the three stereogenic centers in the product were generated in a coupling reaction of 3 with ethyl isocyanoacetate, catalyzed by a gold(I)/chiral ferrocenylphosphine system, giving the dihydrooxazole 5 in 85% diastereoselectivity (mismatchedcase). The weak effect of double stereodifferentiation in this reaction (matched case 90% ds) is discussed. N‐Methylation and hydrolytic ring opening of 5 gave the protected form 7 of MeBmt, The X‐ray diffraction study carried out on 7 confirms the absolute configuration of the two stereogenic centers formed in the gold(I)‐catalytic reaction.
Untersuchungen zur Thermochromie von Heterospiranen und Farbbildnern mit heterocyclischen Teilsystemen und O oder N als Ringschlussatom
Authors: Hellrung Bruno , Balli Heinz 
Published: December 2004

Investigations on the Thermochromism of a Series of Spirocyclic Compounds and ‘Colourformers’ with Heterocyclic Parts and O or N as the ‘Key’ Atom.The thermochromism of a series of spirocyclic compounds with heterocyclic parts and O or N as the ‘key’ atom and of ‘colourformers’ was investigated in different solvents such as benzyl alcohol, dimethyl phthalate, decaline, toluence, or xylene. Thermodynamic data for the involed equilibria (ΔH°, ΔS°, and ΔG°298k) and VIS‐spectroscopic data were determined and discussed in relation to the ones known spiropyrances. Compounds with O as ‘key’ atom behave very similary to the known spiropyrances, compounds with N as ‘key’ atom mostly are unstable undergoing irreversible bleaching. The ‘colour formers’ usually show only small thermochromic effects and very small equilibrium concentration of the coloured form.
Bildung von 5,6‐Dihydro‐1,3(4H)‐thiazin‐4‐carbonsäure‐estern aus 4‐Allyl‐1,3‐thiazol‐5(4H)‐onen
Authors: Jenny Christjohannes , Heimgartner Heinz 
Published: December 2004

Formation of Methyl 5,6‐Dihydro‐l, 3(4H)‐thiazine‐4‐carboxyiates from 4‐Allyl‐l, 3‐thiazol‐5(4H)‐ones.The reaction of N‐[1‐(N, N‐dimethylthiocarbamoyl)‐1‐methyl‐3‐butenyl]benzamid (1) with HCl or TsOH in MeCN or toluene yields a mixture of 4‐allyl‐4‐methyl‐2‐phenyl‐1,3‐thiazol‐5(4H)‐one (5a) and allyl 4‐methyl‐2‐phenyl‐1,3‐thiazol‐2‐yl sulfide (11; Scheme 3). Most probably, the corresponding 1,3‐oxazol‐5(4H)‐thiones B are intermediates in this reaction. With HCl in MeOH, 1 is transformed into methyl 5,6‐dihydro‐4,6‐dimethyl‐2‐phenyl‐1,3(4H)‐thiazine‐4‐carboxylate (12a). The same product 12a is formed on treatment of the 1,3‐thiazol‐5(4H)‐one 5a with HCl in MeOH (Scheme 4). It is shown that the latter reaction type is common for 4‐allyl‐substituted 1,3‐thiazol‐5(4H)‐ones.
The Photochemical Synthesis and Denitrogenation of 8,9‐diazadibenzo[c, e]isobullvalene
Authors: Burger Ulrich , Mentha Yves G. , Millasson Patricia , Lottaz Pierre‐André , Mareda Jiri 
Published: December 2004

AbstractStarting from dibenzo[a, c]cyclooctene (4) and 4‐methyl‐3H‐1,2,4‐triazol‐3,5(4H)‐dione (MTAD), the strained skeleton of the title azo compound 1 is assembled in a tandem photo‐Diels‐Alder addition/di‐π‐methane rearrangement sequence. The synthesis is completed by a stepwise hydrolytic oxidation of the ensuing triazolidine‐dione 2 with nickel peroxide. Thermolysis of 1 in benzene solution is shown to be governed by an initial 1,3‐dipolar cycloreversion which leads, via an intermediate diazo compound 11, to cyclobuta[1]phenanthrene 8 and two further carbene‐derived C16H12 products. Photolysis of 1 at 350 nm leads in modest yield (12%), via a diazenyl diradical, to an unstable bridged bicyclobutane 10 (dibenzooctavalene). MNDO calculations suggest the latter to have a rapidly inverting, twisted structure of C2 symmetry.
Nucleotides. Part. XXXII. Synthesis of 2′–5′ Connected oligonucleotides. Prodrugs for antiviral and antitumoral nucleosides
Authors: Herdewijn Piet , Charubala Ramamurthy , De Clercq Erik , Pfleiderer Wolfgang 
Published: December 2004

AbstractThe cytotoxically and antivirally active compounds bvUd (1), flUd (4), acyclovir (7), and Aa (12) have chemically been combined with the appropriately protected (2′–5′)diadenylate 20 by the phosphotriester approach to give the 2′–5′ oligonucleotide trimers 21–24. The deprotection of the various blocking groups by chemical means afforded the 2′–5′ trimers 25–28, which can be regarded as new type of a potential prodrug form delivering nucleotides to the targets inside cells. In an analogous series of reactions, 9‐(3′‐azido‐3′‐deoxy‐β‐D‐xylofuranosyl)adenine was coupled with 7 to the 2′–5′ trimer 31. The antiviral screening of the oligonucleotides 25–27 and 31 showed biological activities closely related to the parent nucleosides, possibly indicating their release by enzymatic cleavage of the oligomers.
Allobetonicoside and 6‐O‐Acetylmioporoside: Two new iridoid glycosides from Betonica officinalis L.
Authors: Jeker Marianne , Sticher Otto , Çaliş İhsan , Rüedi Peter 
Published: December 2004

AbstractA new allose‐containing iridoid diglycoside, allobetonicoside (1), and a new acyl iridoid glucoside, 6‐O‐acetylmioporoside (2) have been isolated from the aerial parts of Betonica officinalis L. in addition to two known iridoid glucosides, acetylharpagide (3) and reptoside (4). Their structures have been determined by spectroscopic methods as well as by means of chemical evidence.
Molecular‐Graphics Modelling of the Acid Strength in Zeolites: Influence of the Aluminium Distribution in Offretite
Authors: Goursot Annick , Fajula François , Figueras François , Daul Claude , Weber Jacques 
Published: December 2004

AbstractUsing extended Hückel wave functions, molecular electrostatic potentials (MEP's) have been calculated for several model clusters representative of zeolites of offretite type. The clusters studied, which are all made of a central unit comprising 2 AlO4 and 16 SiO4 tetrahedra, differ only by the relative positions of the Al‐atoms occupying the same crystallographic sites (T2) within the zeolite framework. using the MEP values as a color‐coded acidity index for the various clusters, three‐dimensional representations of their molecular surfaces are generated as solid models on a performing computer graphics system. Important differences in acidity are predicted for the clusters which can he classified into two types according to the distribution of Al‐atoms: the first one is characterized by nearly independent acid sites localized around the main channel of zeolite (Figs. 3 and 6) whereas the second one exhibits interacting acid sites located longitudinally along the channel of the same gmelinite cage (Figs. 4 and 5). The possible relationship between the structure of the clusters and their catalytic activity towards organic species is discussed.
1,2,3,4,4a,5,8,8a‐Octahydro‐4β,8aα‐dimethylnaphthalen‐4aβ‐ol ( = Dehydrogeosmin), a Novel Compound Occurring in the Flower Scent of Various Species of cactaceae
Authors: Kaiser Roman , Nussbaumer Cornelius 
Published: December 2004

AbstractThe 1,2,3,4,4a,5,8,8a‐octahydro‐4β8aα‐dimethylnaphthalen‐4aβ‐ol (= dehydrogeosmin; 1) has been identified as the olfactorily dominant compound in the flower scents of Rebutia marsoneri WERD., Dolichothele longimamma (DC.) BR. et R., and Sulcorebutia kruegeri (CARD.) RITT. The structure of 1, which might be of importance to the pollination biology of such Cactaceae, is based on spectral data and synthesis.
Total Syntheses of (−)‐Conduritol B ((−)‐1L‐Cyclohex‐5‐ene‐1,3/2,4‐tetrol) and of (+)‐Conduritol F((+)‐1D‐Cyclohex‐5‐ene‐1,2,4/3‐tetrol). Determination of the Absolute Configuration of (+)‐Leucanthemito
Authors: Le Drian Claude , Vionnet Jean‐Paul , Vogel Pierre 
Published: December 2004

AbstractThe ‘naked sugar’ (+)‐(1R,2R4R)‐2‐endo‐cyano‐7‐oxabicyclo[2.2.1]hept‐5‐sn‐2‐exo‐yl acetate ((+)‐4) was converted (7 steps, 45% overall) with high stereoselectivity into (−)‐(4R,5S,6R)‐4,5,6‐tris{[(tert‐butyl)dimethylsilyl]oxy}cyclohex‐2‐en‐1‐one ((−)‐11). Reduction of (−)‐1 with NaBH4‐ CeCl3 · 7 H2O, followed by deprotection of the silyl ether moieties gave (+)‐conduritol F ((+)‐1; 47%) whose characteristics were identical to those of natural (+)‐leucanthemitol. Reduction of (−)‐11 with DIBAH, followed by deprotection of the silyl ether moiety led to (−)‐conduritol B ((−)‐3; 51 %).
Synthesis and Complexation of 1,2‐Bis[(monoaza[15]crown‐5)‐N‐yl]glyoxime. Crystal Structure of (1,2‐Bis[(monoaza[15]crown‐5)‐N‐yl]glyoximato)palladium(II)
Authors: Ahsen Vefa , Musluoǧlu Emel , Gürek Ayşegül , Gül Ahmet , Bekâroǧlu Özer , Zehnder Margareta 
Published: December 2004

AbstractA new vicinal dioxime ligand with two crown‐ether groups, 1,2‐bis[(monoaza[15]crown‐5)‐N‐Yl]‐glyoxime(LH2), has been prepared from cyanogen di‐N‐oxide and monoaza[15]crown‐5. Ni(II), Pd(II), and Pt(IV) complexes of LH2 with or without alkali‐metal ions bound to macrocyclic groups have been isolated. The high affinity of [Pd(LH)2] and [Ni(LH)2] for the K+ ion is observed in solvent extraction experiments. A single‐crystal X‐ray structure confirms the postulated geometry of [Pd(LH)2]‐ The Pd‐atom of the centro‐symmetric molecule has square‐planar PdN4 coordination where Pd–N distances range from 1.978(3) to 1.970(3) Å. The N–Pd–N intraligand angle is 79.9(1)°.
A Variable‐Pressure 2D 1H‐NMR Study of the Mechanism of Trimethyl Phosphate Intermolecular Exchange and cis/trains‐Isomerisation of Tetrachlorobis(trimethyl phosphate)zirconium(IV)
Authors: Frey Urban , Helm Lothar , Merbach André E. 
Published: December 2004

AbstractIn chloroform, [ZrCl4·2(MeO)3PO] exists in both cis‐ and trans‐isomeric forms. Three reactions can be envisaged in the presence of excess (MeO)3PO = L: (1) cis‐[ZrCl4·2L] + *L⇆cis‐[ZrCl4·L*L]+ L; (2) trans‐[ZrCl4·2L] + *L ⇆ trans‐[ZrCl4·L*L] + L; (3) cis‐[ZrCl4·2L]⇆ trans‐[ZrCl4·2L]. To distinguish between these possible reaction pathways, we have used 2D 1H‐NMR spectroscopy. For the first time, variable‐pressure 2D exchange spectra were used for mechanistic assignments. cis/trans‐Isomerisation was found to be the fastest reaction (in CHCl3/CDCl3), with a small acceleration at higher pressure: it is concluded to be an intramolecular process with a slightly contracted six‐coordinate transition state. The intermolecular (MeO)3PO exchange on the cis‐ and trans‐isomer are second‐order processes and are strongly accelerated by increased pressure: Ia mechanisms are suggested without ruling out limiting A mechanisms.
Blockcopolymers in microemulsions differential heats of solution and shift of the percolation temperature in W/O microemulsions
Authors: Eicke Hans‐Friedrich , Hilfiker Rolf , Xu Gu 
Published: December 2004

AbstractSolutions of blockcopolymers (POE‐b‐PI‐b‐POE) in fluids of interacting aqueous nanodroplets (W/O microemulsions) are studied. The interaction strength between the (pseudo) two components is measured by the shift of the percolation temperature relative to that of the pure microemulsion. A quantitative measure of the interaction, the differential heat of solution, is thermodynamically related to the slopes of the equilibrium temperature of the system with varying monomeric nanodroplet concentration and the experimental percolation line in the presence of copolymer.
Cycloalkylations of N‐(ω‐Halogenoalkyl)‐substituted Macrocyclic Imides
Authors: Ognyanov Vassil I. , Hesse Manfred 
Published: December 2004

AbstractWith ω‐halogenoalkyl isocyanates, 2‐oxocyclododecane‐l‐carbonitrile is transformed under ring enlargement to 1‐(ω‐halogenoalkyl)‐2,14‐dioxo‐1‐azacyclotetradecane‐3‐carbonitriles. In the presence of base, these products undergo O‐ or C‐alkylation leading to bicyclic compounds. The C‐alkylation product 7 undergoes solvolysis to form a sixteen‐membered ring compound.
Synthesis of Aristotelia‐type alkaloids. Part V. Biomimetic synthesis of (±)‐aristomakine and (±)‐aristomakinine
Authors: Burkard Stefan , Borsehberg Hans‐Jürg 
Published: December 2004

AbstractBiomimetic syntheses of racemic aristomakinine ((±)‐3) and aristomakine ((±)‐4), an unusual indole alkaloid bearing an N‐isopropyl group, are described. The key step is a Grob‐type fragmentation of anti‐15‐aristotelinyl methanesulfonate ((±)‐2) to the intermediate iminium ion I which, upon subsequent hydrolysis, furnished aristomakinine ((±)‐3). On the other hand, the same intermediate could be reduced in situ to aristomakine ((±)‐4). The controversial relative configurations of the two alkaloids have been firmly established by means of NOE difference experiments.
Effets de substituant, d'hétéroatome et de solvant sur les cinétiques de décoloration thermique et les spectres d'absorption de photomérocyanines en série spiro[indoline‐oxazine]
Authors: Pottier Eliane , Dubest Roger , Guglielmetti Robert , Tardieu Pascale , Kellmann Arlette , Tfibel Francis , Levoir Patrick , Aubard Jean 
Published: December 2004

Substituent, Heteroatom, and Solvent Effects on the Thermal‐Bleaching Kinetics and Absorption Spectra of Photomerocyanines Issued from Spiro[indoline‐oxazines]Quantitative information useful for the development of new photochromic systems is obtained from the study of heteroatom and substituent effects on the thermal‐bleaching kinetics and the absorption spectra of the photomerocyanines issued from spiro[indoline‐oxazines]. The effect on photochromic properties of the presence of N‐atoms either in the dimethine bridge or in the aromatic rings has been investigated through the comparison of spiro[indoline‐naphthopyrans] C with spiro[indoline‐naphthoxazines] A and with spiro[indoline‐quinolinoxazines] B. Besides the occurrence of biexponential thermal‐bleaching kinetics in non‐polar solvents is observed: a tentative explanation for this observation is given which involves the formation, in either sequential or parallel steps, of energetically distinct stereoisomers of the opened form.
Synthesis of 8‐Aza‐1,3‐dideaza‐2′‐deoxyadenosine and 5,6‐Disubstituted Benzotriazole 2′‐Deoxy‐β‐D‐Ribofuranosides via Nucleobase‐Anion Glycosylation
Authors: Kazimierczuk Zygmunt , Seela Frank 
Published: December 2004

AbstractThe synthesis of 8‐aza‐1,3‐dideaza‐2′‐deoxyadenosine (3a) as well as of 4‐ and 5,6‐substituted benzotriazole 2′‐deoxy‐β‐D‐ribonucleosides is described (Schemes 1–3). Glycosylation of benzotriazole anions is stereoselective in all cases (exclusive β‐D‐anomer formation), but regioisomeric N1, N2, and N3‐(2′‐deoxyribofuranosides) are formed. The distribution of the regioisomers is controlled by the nucleobase substituents. Anomeric configuration as well as the position of glycosylation are determined by UV and NMR in combination with 1D‐NOE‐difference spectroscopy. The unprotonated forms of 4‐aminobenzotriazoic 2′‐deoxy‐β‐D‐ribofuranosides 3a–c exhibit strong fluorescence.
Über Pterin‐Chemie 87. Mitteilung. Regiospezifische Synthese von (Polyhydroxypropyl)‐pterinen: Herstellung von D‐Anapterin und L‐Primapterin
Authors: Viscontini Max , Bosshard René 
Published: December 2004

Regiospecific Synthesis of (Polyhydroxypropyl)‐pterins: Synthesis of D‐Anapterin and L‐PrimapterinCondensation of 2,5,6‐triaminopyrimidin‐4‐one(5) with the semicarbazone of pentoses proceeds regiospecifically with formation of 7‐(polyhydroxypropyl)pterins. D‐Anapterin (=7‐(D‐erythro‐1′,2′,3′‐trihydroxypropyl)pterin; D‐3) was obtained in 40% yield, and L‐primapterin (=7‐(L‐erythro‐1′,2′‐dihydroxypropyl)pterin; L‐4)in 10% yield.
Potential antipsychotic agents. Part 8. Antidopaminergic properties of a potent series of 5‐substituted (−)‐(S)‐N‐[(1‐ethylpyrrolidin‐2‐yl)methyl]‐2,3‐dimethoxybcnzaimides. Synthesis via common lithio intermediates
Authors: Högberg Thomas , Ström Peter , Hall Håkan , Ögren Sven Ove 
Published: December 2004

AbstractA series of 5‐substituted (−)‐(S)‐N‐[(1‐ethylpyrrolidin‐2‐yl)methyl]‐2,3‐diniethoxybenzanndes were made by reaction of the corresponding benzoyl chlorides with (S)‐1‐ethylpyrrolidine‐2‐methylaruine (→ 14–16, 18–21). The acids required were prepared in a regiospecific manner from 5‐bromo‐2,3‐dimethoxybenzoic acid which was protected as dihydrooxazole (→ 4–8), metalated, reacted with various electrophiles (MeI, EtI, BuBr, CC13CCl3 or MeSSMe), and hydrolyzed (→9–13). Alternatively, (‐)‐(S)‐5‐bromo‐N‐[(1‐ethylpyrrolidin‐2‐yl)methyl]‐2,3‐di‐methoxybenzamide was treated with KH followed by BuLi and an electrophile (I2 or Me3SiCl) to give the 5‐iodo and 5‐(trimethylsilyl) derivatives 17 and 22, respectively. All 5‐substituted amides were highly potent inhibitors of [3H]spiperone binding in rat striatal membranes with IC50 values of 0.5 to 5 nM (Table 3). Thus, a relatively large steric bulk can be accomodated in the position para to the 2‐MeO group. This work also supports the notion that a positive as well as negative electrostatic potential can be located in this position. A selected number of derivatives were also investigated in vivo and found to inhibit apomorphine‐induced behavioural responses in the same dose range as haloperidol and raclopride (Table 4). This new group of benzamides is suitable for investigations of dopamine D‐2 receptors in labelled or unlabelled form.
Structure Determination of a New Spirobicyclic Triterpenoid from Iris foetidissima
Authors: Marner Franz‐Josef , Karimi‐Nejad Yasmin , Jaenicke Lothar , Wray Victor 
Published: December 2004

AbstractThe novel iridal 10 has been isolated from rhizome extracts of Iris foetidissima. Its structure was established by spectroscopic methods and oxidative degradation. Final proof of the spirobicyclic nature of the compound – a new feature in the triterpenoid field – was afforded by the correlations observed in the 2D‐HMBC‐ (1H‐detected multiple‐bond heteronuclear multiple‐quantum coherence) spectrum. The possible biogenesis of this unusual compound is discussed.
Further Studies on the Biosynthesis of Tabtoxin (Wildfire Toxin): Incorporation of [2,3‐13C2]Pyruvate into the β‐Lactam Moiety
Authors: Roth Patricia , Hädener Alfons , Tamm Christoph 
Published: December 2004

Abstract[2,3‐13C2]Pyruvic acid (7) was synthesized and administered to cultures of Pseudomonas syringae pv tabaci. C(2) and C(3) of 7 were incorporated as an intact unit into the β‐lactam moiety of tabtoxin (1). The result suggests that the biosynthesis of 1 is proceeding in part along the lysine pathway. The labelling pattern in 1 and an incorporation experiment with α,α′‐dideuterated (±)‐2,6‐diaminopimelic acid (19) indicate that the branching in the biosynthesis of 1 occurs before lysine is formed.