bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel concepts in directed biaryl synthesis, XXXVII. Synthesis and enantiomerization of a nonracemic 2‐hydroxy‐2′‐biarylcarbaldehyde, a probable intermediate in the atropo‐enantioselective ring opening of biaryl lactones
Authors: Bringmann Gerhard , Hartung Thomas 
Published: July 2007

AbstractThe directed preparation of a “free”, i.e. nonprotected biaryl with a phenolic OH function and a formyl group in opposite ortho positions, in a nonracemic form, is described. The free activation barrier ΔG≠ for the atropisomerization, which was determined to be 99.2 kJ mol−1, is far lower than expected for an exclusively physical rotation process and is more likely in agreement with an isomerization via lactol‐type cyclic intermediates previously postulated. magnified image
Selektive Synthese ortho‐disubstituierter Tetrahydroanthracene mit Retinoidstruktur
Authors: Hanefeld Wolfgang , Jung Manfred 
Published: July 2007

Selective Synthesis of ortho‐Disubstituted Tetrahydroanthracenes with Retinoid StructureA synthesis of analogues of Temarotene (Ro 15‐0778) (1) is described. This synthesis achieves the selective substitution in ortho‐positions of a tetrahydroanthracene system using palladium‐catalyzed coupling techniques. magnified image
Synthese, Strukturaufklärung und Reaktionen trans‐verknüpfter 3, 6‐Anhydro‐1, 2‐O‐isopropyliden‐α‐D‐hexofuranosen
Authors: Reckendorf Wolfgang Meyer Zu , Schultz Norbert , Kreimeier Richard 
Published: July 2007

Synthesis, Structure Elucidation and Reactions of trans‐Fused 3, 6‐Anhydro‐1, 2‐O‐isopropylidene‐α‐D‐hexofuranosesUnexpectedly, the reaction of 1, 2‐O‐isopropylidene‐5, 6‐di‐O‐(p‐tolylsulfonyl)‐α‐D‐allofuranose (7) with KCN in ethanol yielded the first trans‐fused 3,6‐anhydro‐hexofuranose 10. Besides by spectroscopic evidence the structure of 10 was proved by transformation to the tosylated acetal 13 which could also be obtained via an independent route. Further reactions of 10 all resulted in opening of the strained ring system yielding acetals (18–22). By blocking the 5‐position with the alkali‐resistant ether function this cyclization could also be achieved by more common reagents like NaH in DMF (32). – By applying this procedure to the corresponding α‐D‐galactofuranose derivative 41 3,6‐anhydro‐α‐D‐galactofuranose 42 could also be obtained albeit in low yield. For comparison purposes the 3,6‐anhydro‐α‐D‐gulo derivative 47 was synthesized from easily accessible 44. magnified image
Amination of Some Nitroisoquinolines with Liquid Methylamine/Potassium Permanganate
Authors: Woźniak Marian , Nowak Krystyna 
Published: July 2007

Abstract5‐Nitro‐, 3‐methyl‐5‐nitro‐, 5, 7‐dinitro‐, 5‐chloro‐8‐nitro‐ and 8‐chloro‐5‐nitroisoquinoline (1a–e) as well as 5‐nitroisoquinoline N‐oxide (1f) are aminated with a liquid methylamine solution of potassium permanganate (LMA/PP) to the corresponding mono‐ or mono‐ and bis(methylamino)‐substituted nitro compounds 2 (a–m). 1‐Nitroisoquinoline (1g) is aminated with LMA/PP to 1‐(methylamino)isoquinoline (2n). Quantum‐chemical calculations for some mononitroisoquinolines suggest that, in general, the experimentally observed regioselectivity of the amination is controlled by an interaction of frontal molecular orbitals (FMO) of the reagents. magnified image
2‐Trifluormethyl‐substituierte Aminosäuren, 19. 2‐Trifluormethylaminosäureester, Bausteine für Trifluormethyl‐substituierte Harnstoff‐, Thioharnstoff‐Derivate und andere potentielle Wirkstrukturen
Authors: Burger Klaus , Schierlinger Christian , Hollweck Wolfgang , Mütze Kerstin 
Published: July 2007

2‐Trifluoromethyl‐Substituted Amino Acids, 19. – 2‐Trifluoromethyl α‐Amino Acid Esters, Building Blocks for Trifluoromethyl‐Substituted Ureas, Thioureas and Other Potential Biological Active StructuresThe preparative value of trifluoromethyl‐substituted building blocks increases with the number of additional functionalities present. 2‐Trifluoromethyl α‐amino acid esters 2 represent readily available starting materials, excellently suited for the introduction of the biologically interesting trifluoromethyl group into a variety of classes of compounds, like ureas 4 and thioureas, acylureas 5 and acylthioureas 12, imidazolidin‐2,4‐diones 8 and imidazolidin‐4‐on‐2‐thiones 11 as well as 2‐isocyanatoalkanoic acids 13. Via the latter Fmoc‐2‐trifluoromethyl α‐amino acid 16a can be readily prepared. magnified image
2‐Trifluormethyl‐substituierte Aminosäuren, 20. N‐ und C‐terminaler Einbau von α‐Trifluormethyl‐substituierten α‐Aminosäuren in Azapeptide
Authors: Burger Klaus , Schierlinger Christian , Mütze Kerstin , Hollweck Wolfgang , Koksch Beate 
Published: July 2007

2‐Trifluoromethyl‐Substituted Amino Acids, 20. – Incorporation of α‐Trifluoromethyl‐Substituted α‐Amino Acids into the N‐ and C‐Terminal Position of AzapeptidesCoupling reactions of α‐trifluoromethyl‐substituted α‐amino acids and azaamino acids via α‐isocyanatocarboxylic acid derivatives are described. magnified image
Sterically Congested Molecules, 11. The 2,6‐Diisopropylphenyl Substituent at CC and CN Groups
Authors: Knorr Rudolf , Ruhdorfer Jakob , Böhrer Petra , Bronberger Hildegard , Räpple Edith 
Published: July 2007

AbstractTwo series of new compounds with sterically shielded, sp2‐hybridized C‐α atoms are prepared from bromo(chloro)‐2,6‐diisopropylbenzene. The α‐(2,6‐diisopropylphenyl) substituent common to all of them is used as an NMR‐spectroscopic indicator for the ease of aryl‐α single‐bond rotation. The corresponding ΔG≠ values are >23.8 kcal/mol with methyl or bromine as additional α substituents at a CC bond, but <8.5 kcal/mol with α‐H. The analogous 2,6‐diisopropylacetophenone imine has ΔG* = 18.0 kcal/mol while the N‐substituted imines prefer the (Z) conformations with ΔG≠ > 23.3 kcal/mol, and ΔG≠ ≈ 31.5 kcal/mol for the (Z)‐hydrazone. Comparisons of these data with reaction conditions show that chemical transformations are not seriously impeded unless they depend on reagent attack at a π face of the C‐α atom in a CC or CN group which rotates slowly about the bond to 2,6‐diisopropylphenyl. magnified image
Unerwartete Reaktion von gemischten Azinen von Dihydrocodeinon mit Methansulfonsäure
Authors: Schmidhammer Helmut , Schwarz Peter 
Published: July 2007

Unexpected Reaction of Mixed Azines of Dihydrocodeinone with Methanesulfonic AcidBy treatment of the mixed azines 7 and 8 with methanesulfonic acid in dimethyl sulfoxide the corresponding pyrroles 9 and 10 were not obtained. In both cases the main product was the pyrrole 11, which was also synthesized from dihydrocodeinone azine (12) by reaction with methanesulfonic acid in dimethyl sulfoxide. magnified image
Asymmetric Synthesis of ent‐Corey Lactone Alcohol and its 12‐(all‐cis)‐ and 11‐Epimers via Free Radical 5‐exo‐trig‐C, C Cyclization
Authors: Mulzer Johann , Kermanchahi Abdul Kader , Buschmann Jürgen , Luger Peter 
Published: July 2007

AbstractAsymmetric eight‐step syntheses are reported for the ent‐Corey lactone alcohol derivatives 3a–d and their epimers 4a–d and 14a, b from (R)‐2,3‐isopropylidene glyceraldehyde (5) as the starting material. The key step of the synthesis is the free radical cyclization of the butenolide thiocarbonates 11, 12 and 13. This reaction produces 3 and 4 in ratios between 57:43 and 30:70 from 11 and 12, whereas 14a and 14b are generated from 13 in a ratio of 19:81. From 3d the prostanoid enone 18 is prepared via the configurationally stable aldehyde 17. magnified image
Synthesis of Dipeptides Containing Novel Cyclopropyl‐ and Cyclopropenyl‐Substituted β‐ and γ‐Amino Acids
Authors: Paulini Klaus , Reißig Hans‐Ulrich 
Published: July 2007

AbstractThe N‐silylated methyl 2‐aminocyclopropanecarboxylate 1 can be incorporated into a dipeptide via a CsF‐mediated condensation reaction with N‐tosylated phenylalanine chloride 5. Due to its instability the corresponding free β‐amino acid 4 could not be isolated up to now, and peptides containing this structural element have previously not been accessible. After desilylation, the aminomethyl‐substituted cyclopropane or cyclopropene derivatives trans‐ 10, 12, and 13 also provided N‐protected dipeptides in good yields. magnified image
Cyclopropandiamine, 4. Synthese und 1H‐NMR‐Spektren diastereomerenreiner 1,2‐Cyclopropandiamine und 1,2‐Cyclopropandiammonium‐dibromide
Authors: von der Saal Wolfgang , Reinhardt Robert , Seidenspinner Hubert‐Matthias , Stawitz Josef , Quast Helmut 
Published: July 2007

Cyclopropanediamines, 4. – Synthesis and 1H‐NMR Spectra of Pure Diastereomers of 1,2‐Cyclopropanediamines and 1,2‐Cyclopropanediammonium DibromidesThe efficient preparation of pure diastereomers of N,N′‐(1,2‐cyclopropanediyl)diurethanes 16–18 and ‐diammonium dibromides 4, 19, and 20 is reported. Curtius rearrangement of cis‐ and trans‐1,2‐cyclopropandicarboxylic dihydrazides 14 yields di(O‐benzyl) diurethanes 16 on a 10‐100 g scale. The cis‐1,2‐cyclopropanedicarboxylic dihydrazides cis‐14 tend to form bicyclic products. Thus, from cis‐14a a small amount of 22a is obtained besides the diurethane cis‐16a. Cyclisation is the main reaction in the case of cis‐1,2‐dimethyl‐1,2‐cyclopropanedicarboxylic hydrazide (cis‐14e) which affords the bicyclic products 22e and 24, but no diurethane. The 1,2‐dimethyl‐1,2‐cyclopropanedicarboxylic acid (27) reacts with diphenyl phosphorazidate to produce the monobenzyl ester 29. The diurethanes 16 are methylated (→ 17) and benzylated (→ 18) at both nitrogen atoms. The benzyloxycarbonyl group is removed from the diurethanes 16–18 by the action of hydrogen bromide in acetic acid to yield the 1,2‐cyclopropanediammonium dibromides 4, 19, and 20. The 1H‐NMR spectra are analysed and the results are employed as criteria for the configurations. magnified image
Tetrahydrofurane und γ‐Lactone, VII. Synthese und Reaktionen von γ,γ‐disubstituierten γ‐Lactonen – ein Weg zu funktionalisierten Dodecandisäure‐Derivaten
Authors: Tochtermann Werner , Weidner Fritjof 
Published: July 2007

Tetrahydrofurans and γ‐Lactones, VII. – Synthesis and Reactions of γ,γ‐Disubstituted γ‐Lactones – an Approach to 4,5‐Functionalized Dodecanedioic Acid DerivativesThe title compounds 5 are obtained by Diels‐Alder reaction of cyclooctyne and 2‐substituted furans, subsequent hydrogenation, ozonolysis and oxidation with air. The lactone ring of 6c is opened by treatment with sodium iodide and zinc to give the methylene carbonyl derivative 9a. Compound 9a is converted into the cyclopropane 13 via the pyrazoline 12. magnified image
Vicarious Nucleophilic Substitution (VNS) of Hydrogen in Azulenes
Authors: Ma̧goikosza Mieczyslaw , Kuciak Renata , Wojciechowski Krzysztof 
Published: July 2007

AbstractAzulene reacts with carbanions bearing a leaving group according to the vicarious nucleophilic substitution (VNS) scheme. Treatment of 6‐chloroazulene with such carbanions affords the VNS reaction and nucleophilic aromatic substitution (SNAr) products. magnified image
Pheromone Synthesis, CLXII. Synthesis of Methyl 2,6,10‐Trimethyltridecanoate, the Male‐Produced Pheromone of the Stink Bugs, Euschistus heros and E. obscurus, as a Stereoisomeric Mixture
Authors: Mori Kenji , Murata Noriaki 
Published: July 2007

AbstractMethyl 2,6,10‐trimethyltridecanoate (1), the male‐produced attractant pheromone of the South American soybean pest, Euschistus heros, and that of E. obscurus, was synthesized as a stereoisomeric mixture and identified by a comparison with the natural product on the basis of GC and MS data. magnified image
The 2‐(Chloroacetoxymethyl)benzoyl (CAMB) Group as a Novel Protecting Group for Carbohydrates
Authors: Ziegler Thomas , Pantkowski Guido 
Published: July 2007

AbstractThe application of the 2‐(chloroacetoxymethyl)benzoyl (CAMB) group to the O‐protection of position 2 in glycosyl donors is described. Saponification of the phthalide and subsequent chloroacetylation of 2‐(hydroxymethyl)benzoic acid (1) gave 2‐(chloroacetoxymethyl)benzoic acid (2). Treatment of 2 with thionyl chloride afforded the acyl chloride 3. Acylation of O‐2 of 1,3,4,6‐tetra‐O‐acetyl‐α‐D‐glucopyranose (4a), galactopyranose (4b) and of the amino group of 1,3,4,6‐tetra‐O‐acetyl‐2‐amino‐2‐deoxy‐β‐D‐glucopyranose (4c) afforded the fully protected pyranose derivatives 5a–c in high yields. Compounds 5a and 5b were converted with HBr in acetic acid into the corresponding 2‐O‐CAMB‐protected bromides 6a, b in excellent yields. Silver trifluoromethanesulfonate promoted glycosylation of the latter with 2‐hydroxyethyl benzoate yielded the β‐glycosides 8a (74%) and 8b (69%). Direct activation of the glucosamine derivative 5c with ferric chloride gave the glucoside 8c (54%). Furthermore, the galactosyl bromide 6b was coupled with methyl 2,3,4‐tri‐O‐benzoyl‐β‐D‐glucopyranoside (11) affording the 2′‐O‐CAMB‐protected methyl glycoside disaccharide 12 (63%). Similarly, condensation of the glucosyl bromide 6a with 4a gave the β‐(1→2)‐linked disaccharide 13 (45%). Treatment of compounds 8a and 13 with thiourea resulted in the deblocked glycosides 9a and 14. Similar deprotection of 8b gave 2‐benzoyloxyethyl 3,4,6‐tri‐O‐acetyl‐β‐D‐galactopyranoside (9b) and the 2‐O‐[2‐(hydroxymethyl)benzoyl] derivative 10. Reaction of 8c with thiourea afforded solely the dechloroacetylated glucoside 9c. magnified image
Stereoselective Synthesis of Steroids and Related Compounds, III. Synthesis of Enantiomerically Pure Hexahydro‐1H‐indenes and Substituted Cyclopentanes as Intermediates for the Synthesis of Steroids
Authors: Groth Ulrich , Taapken Thomas 
Published: July 2007

AbstractThe indene derivative 7 and the 1,2,2,3‐tetrasubstituted cyclopentane derivative 8 have been synthesized in three steps starting from the Hajos‐Wiechert ketone 1. magnified image
Synthesis and Oral Uptake Studies of Lipidic and Glyco‐Lipidic Conjugates of β‐Lactam Antibiotics
Authors: Toth Istvan , Hughes Richard A. , Dekany Gyula , Hillery Anya M. , Ward Peter 
Published: July 2007

AbstractLipidic and glyco‐lipidic cephalosporin conjugates 1c and 1i were synthesised as diastereomeric mixtures to improve their oral absorption. 2‐(tert‐Butoxycarbonylamino)tetradecanoic acid was condensed with thiazole 1d and by following basecatalysed hydrolysis of the fully protected rac‐1e, the free acid rac‐1f was produced. This was then used to acylate the carboxy‐protected cephalosporin analog 1g by using a modified Vilsmeier reaction. Removal of the protecting groups of 1b resulted in conjugate 1c. Cephalosporin conjugate li, which contains a sugar moiety in addition to a lipidic amino acid residue, was synthesised to produce a drug conjugate with both lipophilic and hydrophilic properties [radiolabelled (14C) analogs 1a, 1c and 1i were also synthesised]. The radio‐labelled parent 1a and conjugates 1c and 1i were administered orally to rats and uptake of the radiolabel in the blood, various organs, urine and faeces was determined. The results showed that an increase in lipophilicity caused an increase in the oral uptake, suggesting that conjugation to lipidic amino acids and peptides is a useful approach to the improvement of the absorption of poorly absorbed drugs. magnified image
Stereoselective Synthesis of Steroids and Related Compounds, V. Synthesis of (±)‐Chokol A by a Tandem Michael‐Addition/Dieckmann Cyclization
Authors: Groth Ulrich , Halfbrodt Wolfgang , Köhler Thomas , Kreye Paul 
Published: July 2007

AbstractA total synthesis of (±)‐chokol A (rac‐12) was accomplished in five steps by starting from the α,β‐unsaturated ester (E)‐2 in an overall yield of 24%. The key step of this synthesis is the tandem conjugate addition/Dieckmann cyclization of the cuprate derived from vinyl bromide 9 with the α,β‐unsaturated ester (E)‐2.
The First Synthesis of Azapterocarpans and Azaisoflavans: A Convenient Route to 3‐Aryl‐1,2,3,4‐Tetrahydroquinolines
Authors: Tőkés Adrienne L. , Antus Sándor 
Published: July 2007

AbstractThe first synthesis of the 5,6,6a,11a‐tetrahydro[1]benzofuro[3,2‐c]quinolines (5‐azapterocarpans) 1–4 has been achieved by palladium‐catalyzed arylation of the appropriately substituted 1,2‐dihydroquinolines 15, 16. The 5‐azapterocarpans 3 and 4 have been transformed into the 3‐aryl‐1,2,3,4‐tetrahydroquinolines (azaisoflavans) 24 and 26, respectively, by reduction with Red‐Al®.
Chiral Polymethine Dyes, III. Synthesis and Spectroscopic Properties of an Unsymmetrical, Chiral Monomethine Cyanine Dye with a Thiazolyl and Quinolyl End Group
Authors: Reichardt Christian , Budnik Ulrich 
Published: July 2007

AbstractThe synthesis of the unsymmetrical monomethine cyanine dye 6 in its monochiral (6a, b) and isochiral form (6c), first realized by Götze in 1938, has been significantly improved and its spectroscopic properties have been studied. According to the synthetic pathway, the stereogenic center in dye 6 is delivered by monochiral 1‐phenylethylamine.
Sterically Congested Molecules, 12. Acidity Constants of Sterically Shielded Protonated Imines in Hydroxylic Solvents
Authors: Knorr Rudolf , Ferchland Kathrin , Hoang Thi Phung 
Published: July 2007

AbstractNMR spectra in combination with pH measurements are shown to provide a simple and convenient procedure for determining the basicities of imines which are either slowly hydrolyzed (4, 5) or completely stable but inconveniently weak bases (11–13). The method has the advantage that it does not require any precise knowledge of the concentrations of the substrates or reagents. N‐Alkyl (4, 15) and N‐unsubstituted imines (5, 8, 9, 14) show quite similar basicities with a weak solvent dependence (from pure water to 99.5% methanol) which is akin to that of pyridine. The N‐aryl imines 10–13 are less basic by ca. 4 pK units. It is concluded that spatial solvent exclusion by bulky substituents has remarkably little effect on the pKa′ values.
Synthesis of 3‐Acyl‐5,6‐dihydro‐2‐phenylthieno(‐furo‐)[2,3‐d]pyrimidin‐4(3H)‐ones
Authors: Maruoka Hiroshi , Yamagata Kenji , Yamazaki Motoyoshi 
Published: July 2007

AbstractThe reactions of 2‐benzamido‐4,5‐dihydro‐3‐thiophene(‐3‐furan‐)carbonitriles 1a–c (and 11a–c) with acetic (or propionic) anhydride in the presence of tin(IV) chloride give the corresponding 3‐acetyl‐5,6‐dihydro‐2‐phenylthieno(‐furo‐)‐[2,3‐d]pyrimidin‐4(3H)‐ones 2a–c (and 12a–c) or 5,6‐dihydro‐2‐phenyl‐3‐propionylthieno(‐furo‐)[2,3‐d]pyrimidin‐4(3H)‐ones 3a–c (and 13a–c). Hydrolysis of compounds 2a–c (and 12a–c) or 3a–c (and 13a–c) leads to the corresponding N‐acetyl‐2‐benzamido‐4,5‐dihydro‐3‐thiophene‐(‐3‐furan‐)carboxamides 4a–c (and 14a–c) or 2‐benzamido‐4,5‐dihydro‐N‐propionyl‐3‐thiophene‐(‐3‐furan‐)carboxamides 5a–c (and 15a–c). The reaction of compounds 4a, b (or 14a, b) with acid anhydrides in the presence of potassium carbonate or triethylamine gives the corresponding 3‐acyl‐2‐benzamido‐4,5‐dihydrothiophenes (or furans) 9, 10, 16, and 17.
Synthesis and Stereochemistry of Some New Diazatricyclic Compounds
Authors: Scheiber Pál , Nemes Péter 
Published: July 2007

AbstractThe diazatricyclic ketone 3 was synthesized by a double Mannich condensation starting from 2‐quinolizidone (2). Reductions of 3 by complex hydrides and hydrazine gave a mixture of isomeric amino alcohols rac‐4/5 and the diamine 6, respectively. Compounds rac‐4 and rac‐5 could be separated by selective acylation with 4‐chlorobenzoyl chloride due to the fundamental steric differences in the N → O acyl transfer interactions within the isomeric molecules. The cis‐ and trans‐4‐phenyl‐2‐quinolizidones (rac‐10, rac‐11) also underwent a Mannich condensation affording the same product rac‐12 in both cases.
Pheromone Synthesis, CLXIV. Synthesis of (2S, 6Z)‐6,8‐Nonadien‐2‐ol, a Pheromone Component of the Leafminer Nepticula malella, and Its Antipode
Authors: Mori Kenji , Ogita Haruhisa 
Published: July 2007

AbstractBoth the enantiomers of (Z)‐6,8‐nonadien‐2‐ol were synthesized via lipase‐catalyzed asymmetric hydrolysis of the acetate of its racemate, which was prepared from ethyl levulinate.
Biologically Active Metabolites from Fungi, 5. Palmarumycins C1–C16 from Coniothyrium sp.: Isolation, Structure Elucidation, and Biological Activity
Authors: Krohn Karsten , Michel Andreas , Flörke Ulrich , Aust Hans‐Jürgen , Draeger Siegfried , Schulz Barbara 
Published: July 2007

AbstractTwelve new spiro acetal metabolites, the palmarumycins C1–C8, (1–8), C11 (11), C12 (12), C15 (15), C16 (16), and three known representatives (10, 13, 14) of this new class of antibiotics were isolated from Coniothyrium sp. The compounds show antibacterial, antifungal and herbicidal activity at concentrations of 10−6–10−4 mol/l. The structures of palmarumycin C2 (2), palmarumycin C3 (3), and palmarumycin C5 (5) were confirmed by X‐ray structure analysis.
Synthese von Azaanalogen der Ascorbinsäure und der Isoascorbinsäure
Authors: Stachel Hans‐Dietrich , Zeitler Klaus , Lotter Hermann 
Published: July 2007

Synthesis of Azaanalogues of Ascorbic Acid and Isoascorbic AcidThe synthesis of the hitherto unknown azaanalogues of ascorbic acid (±)‐10b and isoascorbic acid (±)‐10a is described. The aldol‐type reaction of the tetramic acid derivative 4 with benzyloxyacetaldehyde gives rise to a mixture of the adducts (±)‐5a and (±)‐5b. By X‐ray analysis 5b proved to represent the threo isomer. Catalytic debenzylation of both adducts 5 to the glycols 9 was successful only with 5a leading to 9a. On the other hand, both isomers (±)‐9a and (±)‐9b have been obtained from the aldols 6a/6b by successive debenzylation and desilylation. Removal of the remaining protective group from 9a/9b yielded racemic N‐benzylazaisoascorbic acid and racemic N‐benzylazaascorbic acid, respectively.
Synthesis of Medium and Large Ring Compounds, XXXVIII. Ring Enlargement of Cyclodecanone by a Chiral Building Block: Synthesis and Olfactory Properties of (12R)‐(+)‐12‐Methyl‐13‐Tridecanolide
Authors: Kraft Philip , Tochtermann Werner 
Published: July 2007

AbstractThe title compound (+)‐3 was synthesized in four steps by ring enlargement of cyclodecanone (6) with the chiral building block 5. The protected hydroxy halide 5, easily prepared from commercially available (2S)‐(+)‐methyl 3‐hydroxy‐2‐methylpropanoate (4), was introduced by HMPA‐mediated enolate alkylation and subsequent formation of the cyclic enol ether 8. Ozonolysis and mild chemoselective reduction of the carbonyl function led to the optically active target molecule (+)‐3, which possesses a very interesting clear musk note with elegant sandalwood aspects.
Zur Dimerisierung von Indolizinen an Palladium‐Kohle
Authors: Kreher Thomas , Sonnenschein Helmut , Schmidt Lothar , Hünig Siegfried 
Published: July 2007

Dimerisation of Indolizines by Palladium CoalOxidative dimerisation of some indolizines by Pd/C in p‐xylene was undertaken in order to evaluate reaction conditions for cyclophane syntheses. Surprisingly, alkylation by the solvent occurred at the 3‐position of the indolizines 2 and 5 as a side reaction. In toluene, yields of alkylation products 4b and 8 exceeded those of dimerisation products 3 and 6. The alkylation by the solvent was fully suppressed by using chlorobenzene or chlorotoluene. Alkylation products of indolizines with p‐xylene or toluene and previously unknown dimeric indolizines are described.
Axiceramide A and B, Two Novel tri‐α‐Glycosylceramides from the Marine Sponge Axinella sp.
Authors: Costantino Valeria , Fattorusso Ernesto , Mangoni Alfonso , Aknin Maurice , Gaydou Emil M. 
Published: July 2007

AbstractTwo new glycosphingolipids, axiceramide A (1a) and B (2a), have been isolated as their peracetates (1b and 2b, respectively) from the marine sponge Axinella sp., and their structures elucidated by spectroscopic and chemical analysis. Axiceramide A and B, both composed of a complex mixture of homologues, are the first example of natural triglycosylceramides with three hexopyranose units all engaged in α‐glycosidic linkages.
The Redox Pair Vitamin E and Vitamin C, A 13C‐NMR Study
Authors: Wijesundara Muthu B. J. , Berger Stefan 
Published: July 2007

AbstractVitamin E is oxidized with iodine and the oxidation product reduced with vitamin C with 13C‐NMR monitoring. It is shown that both the tocopheryl radical and the tocopherylquinone are reduced back to vitamin E by ascorbic acid.