bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die massenspektrometrische retro‐Diels‐Alder‐Reaktion: 1, 2, 3, 4‐Tetrahydroisochinolin und 1, 2, 3, 4‐Tetrahydronaphthalin (Tetralin). 31. Mitteilung über massenspektrometrische Untersuchungen
Authors: Gretler Rudolf , Askitol̈ Elefteria , Kühne Hardy , Hesse Manfred 
Published: December 2004

The Mass Spectral retro‐Diels‐Alder‐Reaction: 1,2,3,4‐Tetrahydroisoquinoline and 1,2,3,4‐Tetrahydronaphthaline (Tetraline)The retro‐Diels‐Alder reaction of 1,2,3,4‐tetrahydroisoquinoline and of its N‐acetyl derivative was confirmed on the basis of labelled derivatives (Scheme 2). Furthermore, the loss of ethylene was investigated with the 1,2,3,4‐tetrahydronaphthalene‐ and 1,2,3,4‐tetrahydronaphthalen‐1‐one‐derivatives given in Schemes 4, 5 and 6. In the case of the 1,2,3,4‐tetrahydronaphthalen‐1‐one‐derivatives ethylene is lost via a retro‐Diels‐Alder reaction. The loss of ethylene from 1,2,3,4‐tetrahydronaphthalene (1) and from its derivatives is a rather complex reaction (Scheme 8): 1/3 of ethylene is split off 1+ via a formal retro‐Diels‐Alder reaction, 2/3 are lost after a specific rearrangement. The ratio of these two fragmentation pathways depends very much on the substituents placed at the aliphatic and the aromatic rings, compare e.g. Table 4.
[1,2,3]Triazoloazine/(Diazomethyl)azine Valence Tautomers from 5‐Azinyltetrazoles
Authors: Wentrup Curt 
Published: December 2004

Abstract[1,2,3]Triazoloazines are formed by thermolysis of 5‐azinyltetrazoles in the gasphase or in solution. Thus, 5‐(2‐pyridyl)tetrazole (7) and 5‐(2‐pyrazinyl)tetrazole (11) yield [1,2,3]triazolo[1,5‐a]pyridine (9) and [1,2,3]triazolo[1,5‐a]pyrazine (13), respectively, at 400°/10−3 ‐ 10−5 Torr. 5‐(2‐Phenyl‐4‐quinazolinyl)tetrazole (15) gives 5‐phenyl[1,2,3]triazolo[1,5‐c]quinazoline (17) in 75% yield by heating under reflux in mesitylene solution. 2‐(Diazomethyl)pyridine (8), a valence tautomer of 9, can be trapped by fumaronitrile, leading to 3‐(2‐pyridyl)‐1, 2‐cyclopropanedicarbonitrile (19). The [1,2,3]triazoloazines undergo base catalysed H/D‐exchange in D2O solution.
Zur Aktivierung partiell silylierter Kohlenhydrate mittels Triphenylphosphan/Azodicarbonsäureester
Authors: Brandstetter Hannelore H. , Zbiral Erich 
Published: December 2004

On the Activation of Partially Silylated Carbohydrates Using Triphenylphosphane/DiethylazodicarboxylateReaction of methyl α‐D‐glucopyranoside (1) with two equivalents of t‐butyldimethylchlorosilane yields methyl 2,6‐bis[O‐(t‐butyldimethylsilyl)]‐α‐D‐glucopyranoside (1a) and methyl 3,6‐bis[O(t‐butyldimethylsilyl)]‐α‐D‐glucopyranoside (1b) in a ratio of 4:1. The anomeric β‐pyranoside 2 affords methyl 2,6‐bis[O(t‐butyldimethylsilyl)]‐β‐D‐glucopyranoside (2a) and methyl 3,6‐bis[O(t‐butyldimethylsilyl)]‐β‐D‐glucopyranoside (2b) in nearly equal amounts. 2b is isomerized to methyl 4,6‐bis[O(t‐butyldimethylsilyl)]‐β;‐D‐glucopyranoside (2c) (83%) and 2a (10%) with triphenylphosphane/diethylazodicarboxylate. Structures were assigned by NMR.‐analysis and CD.‐analysis of the corresponding benzoates 1c, 1d and 2d and of the acetates 2e and 2f.1a is transformed into methyl 4‐azido‐2, 6‐bis[O(t‐butyldimethylsilyl)]‐4‐deoxy‐α‐D‐galactopyranoside (3) with triphenylphosphane/diethylazodicarboxylate/HN3. 2a and 2c yield the 3‐azido‐allosides 5 and 7 respectively under similar conditions. The activation by triphenylphosphane/diethylazodicarboxylate is high enough to introduce also p‐nitrobenzoate groups with inversion of configuration at the reaction center. By this way 1a and 2a give methyl 2, 6‐bis[O(t‐butyldimethylsilyl)]‐4‐O‐p‐nitrobenzoyl‐α‐D‐galactopyranoside (4) and methyl 2, 6‐bis[O‐(t‐butyldimethylsilyl)]‐3‐O−ptrobenzoyl‐β‐D‐allopyranoside (6) respectively. For elucidation of structures the acetate derivatives 3a‐7a were prepared.
Chemically modified silicon dioxide surfaces. Wetting properties of compact n‐alkyl‐dimethylsiloxy layers, and their mixed surface crystals. The Question of Wetting of Molecularly Rough and of Swollen Surfaces
Authors: Riedo François , Czencz Maria , Liardon Olivier , Kováts Ervin sz. 
Published: December 2004

AbstractBy means of contact angle measurements, it has been shown that compact alkyl‐dimethyl‐siloxy layers can be obtained on the surface of acid leached glass using the method previously developed for fume silica. Subsequently, a series of densest possible alkyl‐dimethylsiloxy layers were prepared having non‐branched alkyl substituents, CzH2z+1, (with z=1, 2, 3, 6, 10, 14, 18 and 22) and wetting angles were measured as a function of the temperature. On surfaces coated with longer alkyl substituents the formation of mixed crystals, consisting of the sparse chemically bonded alkyl layer and a n‐alkane acting as a wetting agent, has been observed at low temperatures. At higher temperatures such surfaces appeared to be «molten», and at the same time swollen by the wetting agent. Equations have been derived to deduce the free surface energies and to account for the wetting properties of rough and swollen surfaces. Application of the results to the data presented in this paper revealed that glass surfaces covered with short alkyl chains (methyl, ethyl and propyl) are rough and those covered with long chains (tetradecyl, octadecyl and docosyl) are swollen. Surfaces formed by hexyl‐ and decyl‐dimethylsiloxy substituents exhibit intermediate properties.
Esters phosphoriques, phosphonates et oxydes de phosphine dérivés de sucres. Communication préliminaire
Authors: Tronchet Jean M. J. , Neeser Jean‐Richard , Charollais Etienne J. 
Published: December 2004

Some sugar phosphates, phosphonates and phosphine oxides, Preliminary communicationSome new phosphates of 1, 2‐O‐isopropylidene‐α‐D‐ribofuranose have been prepared. Reactions of 3‐C‐cyanomethylidene‐3‐deoxy‐1, 2‐O‐isopropylidene‐5‐O‐trityl‐α‐D‐erythro‐pentofuranose (9) have been studied. On treatment with phosphorus nucleophiles, 9 led to phosphorus bearing branched‐chain sugar derivatives. Branched‐chain cyanosugars as 15 and 16 prepared by cis‐vic‐dihydroxylation of 9 constitute interesting potential precursors of new types of cyclic sugar phosphates.
Edulon A, ein 2H‐1‐Oxapyrenderivat aus Plectranthus edulis (Labiatae)
Authors: Buchbauer Gerhard , Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

Edulon A, a Derivative of 2H‐1‐Oxapyrene from Plectranthus edulis (LabiataeFrom the coloured leaf‐glands of the above mentioned East‐african labiate we have isolated Edulon A, A new, deeply coloured diterpenoid. Based mainly on spectroscopic arguments, we propose its structure to be (5a R, 1′ ζ)‐10‐(2′‐acetoxy‐1′‐methylethyl)‐6, 7, 9‐trihydroxy‐3, 5a‐dimethyl‐4, 5, 5a, 8‐tetrahydro‐2H,‐l‐oxapyrene‐2, 8‐dione (1a). The compound may be regarded as a 4, 5‐seco‐abietane derivative that has formed new bonds (between C(18 or 19)COOH and C(12)OH), and between C(3) and C (11)) by lactonisation and condensation, respectively.
Biosynthesis of Mikrolin
Authors: Chexal Kuldip K. , Tamm Christoph 
Published: December 2004

AbstractMikrolin (8) and dechloromikrolin (9) have been shown to exist as tautomeric mixtures in solution. The structures of mono‐O‐trifluoroacetyl Mikrolin (10) and di‐O‐acetyl Mikrolin (11) have been elucidated. The products 15 to 23 from reduction of the metabolites 8 9 with Pd/C and Zn in aqueous acetic acid have been identified. The 13C‐NMR. spectra of Mikrolin (8) and dechloromikrolin (9) and their derivatives have been completely assigned Based on the results of incorporation experiments with sodium [1‐13C]‐, [2‐13C]‐ and [1, 2‐13C]‐acetate, a biosynthetic pathway is proposed for Mikrolin (8).
Chloracylierung und Bromacylierung von Carbonylverbindungen: Eine in Vergessenheit geratene Carbonylreaktion. I. Präparative Anwendungsbreite
Authors: Neuenschwander Markus , Bigler Peter , Christen Klaus , Iseli Rudolf , Kyburz Rolf , Mühle Hansueli 
Published: December 2004

Chloroacylation and bromoacylation of carbonyl compounds: A forgotten carbonyl reaction. I. Scope of the reactionAliphatic, α,β‐unsaturated and aromatic aldehydes as well as aliphatic ketones react with acyl halides to (α‐haloalkyl)esters. These bifunctional derivates contain two leaving groups of different reactivity. The scope of this scarcely of this scarcely known carbonyl reaction is discussed.
Chloracylierung und Bromacylierung von Carbonylverbindungen. II. Analyse der Nebenprodukte
Authors: Bigler Peter , Schönholzer Stefan , Neuenschwander Markus 
Published: December 2004

Chloroacylation and bromoacylation of carbonyl compounds II. Structure of the by‐productsThe structures of the by‐products formed in the reaction between paraformaldehyde and acetyl chloride as well as between acetaldehyde and acetyl chloride are elucidated. Optimum conditions for a high yield of the (α‐chloroalkyl) ester 1 were obtained by variation of structure and reaction parameters. A speculative reaction scheme of the formation of by‐products is discussed.
Gleichgewichtsgeometrie und spektroskopische Eigenschaften des Biphenyls im S0‐und S1‐Zustand
Authors: Gustav Klaus , Sühnel Jürgen , Wild Urs P. 
Published: December 2004

Equilibrium geometry and spectroscopic properties of biphenyl in the S0 and S1 stateEquilibrium geometries for the S0 and S1 state of biphenyl were determined by minimization of the total energy with respect to all cartesian coordinates. The molecule is twisted in the S0 state (20°), but becomes planar in the S1 state. Using these results, an interpretation of the fluorescence and absorption spectra can be given. In passing from the S0 to the S1 state equilibrium geometry a remarkable change of the state ordering occurs.
Chloracylierung und Bromacylierung von Carbonylverbindungen. III. Lage des Gleichgewichts
Authors: Bigler Peter , Neuenschwander Markus 
Published: December 2004

Chloroacylation and Bromoacylation of Carbonyl Compounds III. Reactant/Product EquilibriaAliphatic, α, β‐unsaturated and aromatic aldehydes 1 as well as aliphatic ketones react with acyl halides 2 to α‐haloalkyl esters 3. In the presence of Lewis acids there is an equilibrium between reactants and product. The position of the equilibrium depends on the nature of the carbonyl compound as well as that of the acyl halide: The products 3 are favoured in the case of aldehydes, cyclobutanone and cyclohexanone, and the equilibrium constant increases in the series F < Cl < Br < I. Low reaction temperature, nonpolar solvents as well as high reactant concentrations favour the product 3.
Cyclodextrin chemistry. Selective modification of all primary hydroxyl groups of α‐ and β‐cyclodextrins
Authors: Boger Joshua , Corcoran Richard J. , Lehn Jean‐Marie 
Published: December 2004

AbstractTwo efficient methods are described for the selective modification of all six primary hydroxyl groups of α‐cyclodextrin (α‐CD, 11). One, using an indirect strategy, involves protection of all 18 hydroxyl functions as benzoate esters, followed by selective deprotection of the six primary alcohol groups. The other, using a direct strategy, involves selective activation of the primary hydroxyl groups via a bulky triphenylphosphonium salt, which is then substituted by azide anion as the reaction proceeds. A number of modified α‐cyclodextrin derivatives have been prepared and fully characterized, among which are: the useful intermediate α‐cyclodextrin‐dodeca (2, 3) benzoate (3); hexakis (6‐amino‐6‐deoxy)‐α‐cyclodextrin hexahydrochloride (7); hexakis (6‐amino‐6‐deoxy)‐dodeca (2, 3)‐O‐methyl‐α‐cyclodextrin hexahydrochloride (9), hexa (6)‐O‐methyl‐α‐cyclodextrin (13). The direct substitution is shown to be even more efficient for β‐cyclodextrin (16), giving the heptakis (6‐azido‐6‐deoxy)‐β‐CD‐tetradeca (2, 3)acetate (17), while the indirect strategy fails. The compounds are characterized by extensive use of 13C‐ and 1H‐NMR. spectroscopy. The steric and statistical problems of selective polysubstitution reactions for the cyclodextrins are discussed, and possible reasons for the observed differences in reactivity between α‐ and β‐cyclodextrins are examined.The dodecabenzoate 3 presents a very marked solvent effect on physical properties (IR. and NMR. spectra, optical rotation); the effects observed may be ascribed to an unusually strong intramolecular network of hydrogen bonds which severely distorts the α‐cyclodextrin ring and lowers the symmetry from six‐fold to three‐fold.
Über Pterinchemie 67. Mitteilung Zum Verlauf der katalytischen Reduktion von 6, 7‐Diphenylpterin
Authors: Antoulas Symeon , Bieri Jost H. , Viscontini Max 
Published: December 2004

On the pathway of the catalytic reduction of 6,7‐diphenylpterinThe pathway of the hydrogen addition to the pyrazine ring of 6, 7‐diphenylpterin (1a) during acid‐catalyzed reduction was elucidated. Initial hydrogenation of the 5, 6‐double bond produces 6, 7‐diphenyl‐5, 6‐dihydropterin (2a); this then undergoes a [1, 2]‐H‐rearrangement, which yields the thermodynamically more stable 6, 7‐diphenyl‐7, 8‐dihydropterin (3a).Subsequent reduction of 3a gives 4.
An Enantioselective Total Synthesis of Natural (+)‐Luciduline
Authors: Oppolzer Wolfgang , Petrzilka Martin 
Published: December 2004

AbstractThe naturally occurring Lycopodium alkaloid (+)‐luciduline (1) has been synthesized from (R)‐5‐methyl‐cyclohex‐2‐en‐1‐one (12) by a sequence of seven steps (s. Scheme 6) in 33% overall yield. The key step 4→6 presumably involves a transient nitrone 5 which undergoes a highly regioselective intramolecular addition to a non‐polarized olefinic bond.
Preference for Syn Ene Additions of 1O2 to Trisubstituted, Acyclic Olefins
Authors: Schulte‐Elte Karl H. , Muller Bernard L. , Rautenstrauch Valentin 
Published: December 2004

AbstractDye‐sensitized photooxygenations of 3 pairs of (E)/(Z) trisubstituted olefins were studied in order to establish the partitioning between the 3 possible ene additions. The (E)‐isomers underwent only the 2 ene additions (>95%) involving H‐atom abstractions at the same, disubstituted side of the olefins, termed syn ene additions, with almost equal ease. The (Z)‐isomers underwent mainly (85‐90%) the syn ene additions, with the ones leading to the tertiary hydroperoxides distinctly favoured, and some (10‐15%)ene additions at the monosubstituted side of the olefin, termed anti ene addition.
Über 3,3,6,9,9‐Pentamethyl‐2,10‐diaza‐bicyclo‐[4.4.0]‐1‐decen und einige seiner Derivate. Über synthetische Methoden. 13. Mitteilung
Authors: Heinzer Franz , Soukup Milan , Eschenmoser Albert 
Published: December 2004

3,3,6,9,9‐Pentamethyl‐2,10‐diaza‐bicyclo[4.4.0]‐1‐decen and some of its derivativesA simple synthesis for the bicyclic amidine 1 (Scheme 3) is described. This base and the salts which were prepared from it show solubility characteristics which make the amidine a potentially useful reagent for salt formation of carboxylic acids and related proton complexes of bidentate ligands. Among the derivatives made from 1 are the sterically strongly hindered N‐alkylated amidines 11, 12 and 14 (Scheme 5), as well as the stable crystalline N1‐oxidoamidine‐N2‐oxyl radical 2 (Scheme 6). The ability of the latter to serve as a paramagnetic chelating ligand for metal ions is illustrated by the preparation of a corresponding nickel(II) complex. The radical is also a source for the α‐nitronyl‐nitrosonium cation 4 which shows in its reactivity towards conjugated dienes and olefines some of the expected resemblance to singlet oxygen.
Anil‐Synthese 18. Mitteilung. Über die Herstellung von Styryl‐Derivaten des 3‐Phenyl‐benzisoxazols
Authors: De Sousa Benardo F. S. E. , Siegrist Adolf Emil 
Published: December 2004

Preparation of styryl derivatives of 3‐phenyl‐benzisoxazole3‐(p‐Tolyl)‐1,2‐or 2, 1‐benzisoxazoles and 6‐methyl‐3‐phenyl‐1,2‐benzisoxazoles react with anils of aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide or potassium t‐butoxide to yield the corresponding 3‐(stilben‐4‐yl)‐1,2‐ or 2,1‐benzisoxazoles and the 3‐phenyl‐6‐styryl‐1,2‐benzisoxazoles respectively (‘Anil Synthesis’). Further, the Schiff's bases derived form chloroanilines and 3‐(p‐formylphenyl)‐1,2‐benzisoxazoles yield, with methyl‐and p‐tolyl substituted heterocyles the corresponding heterocyclic substitued styryl and stilbenyl derivatives.
Zur Kenntnis der β‐Lysin‐Mutase‐Reaktion: Mechanismus und sterischer Verlauf
Authors: Rétey János , Kunz Fritz , Arigoni Duilio , Stadtman Thressa C. 
Published: December 2004

Investigations on the β‐lysine mutase reaction: Mechanism and steric courseThe steric course and some mechanistic aspects of the coenzyme‐B12‐dependent β‐lysine‐mutase reaction, in which (3 S)‐β‐lysine is converted to (3 S, 5 S)‐3, 5‐diaminohexanoate, have been investigated by means of tritium labelling. The reaction involves migration of an hydrogen atom from C(5) of the substrate to C(5′) of coenzyme B12 and back‐transfer to C(6) of the product. In the presence of [5′‐3H]‐coenzyme B12 the enzyme catalyzes the exchange of label between the cofactor and one of the diastereotopic H‐atoms at C(5) of the substrate. The exchangeable hydrogen atom is identical with the one specifically involved in the migration reaction. Degradation of the tritiated β‐lysine obtained in such experiments yielded a sample of tritiated succinic acid which was shown in an enzymic assay involving partial oxidation with succinate dehydrogenase, to possess the (S)‐configuration. Thus, the overall substitution at C(5) occurs with inversion of configuration.
Stereochemie der Bildung und Spaltung der (CoC)‐Bindung an einem Vitamin‐B12‐Modell 3. (vorläufige) Mitteilung
Authors: Walder Lorenz , Rytz Gerhard , Meier Kurt , Scheffold Rolf 
Published: December 2004

Stereochemical Course of the Formation and Cleavage of the CoC Bond in a Vitamin B12 ModalThe electrosynthesis and properties of a chiral cobalt alkyl complex 4 are described. The reductive cleavage of the Co–C bond occurs with retention of configuration at the C‐atom.
1, 5, 6, 7‐Tetrahydro‐2H‐[1,4]diazepin‐5,7‐dione aus Malonimiden und 3‐Dimethylamino‐2,2‐dimethyl‐2H‐azirin
Authors: Scholl Bernhard , Bieri Jost H. , Heimgartner Heinz 
Published: December 2004

1, 5, 6, 7‐Tetrahydro‐2H‐[1, 4]diazepin‐5, 7‐diones from Malonimides and 3‐Dimethylamino‐2, 2‐dimethyl‐2H‐azirineReaction of the aminoazirine 1 with malonimides of type 7 in 2‐propanol at room temperature leads to the 1,4‐diazepine derivatives of type 9 (Scheme 3). The structure of 6, 6‐diethyl‐3‐dimethylamino‐2,2‐dimethyl‐1,5,6, 7‐tetrahydro‐2H‐ [1,4] diazepin‐5, 7‐dione (9a) has been proved by single crystal X‐ray analysis (Chapter 4). Reduction of the 7‐membered heterocycle 9a with sodium borohydride yields the perhydro‐[1,4]diazepin‐5, 7‐dione 10, while 9a in ethanol at 60° undergoes a ring contraction to the 4 H‐imidazole derivative 11a (Scheme 4): Mechanisms of these two reactions are discussed in comparison with previously reported reactions (Chapter 5).
A New Method for the Construction of Macrolides Stereoselective Synthesis of (±)‐Phoracantholide J. Preliminary communication
Authors: Petrzilka Martin 
Published: December 2004

AbstractStarting from 5‐chloro‐2‐pentanone (1) the naturally occurring 10‐membered lactone phoracantholide J (8a) has been synthesized as its racemate in a sequence of six steps (Scheme 2). Salient features of the syntheis include an internal selenium assisted acetal formation (4→5) and a stereoselective Claisen rearrangement (6→7→8). This general synthetic strategy offers an alternative approach towards the construction of macrocyclic lactones.
A New Type of Claisen Rearrangement Involving 1,3‐Dipolar Intermediates. Preliminary communication
Authors: Malherbe Roger , Belluš Daniel 
Published: December 2004

AbstractDuring the reaction of allyl ethers, allyl sulfides and allyl selenides with in situ prepared dichloroketene (1), 2 competing pathways are observed. Besides [2+2]‐cycloaddition, an unprecedented [3,3]‐sigmatropic (Claisen) rearrangement via a 1,3‐dipolar intermediate takes place. It leads to O‐, S‐ or Se‐esters of α,α‐dichloro‐γ, δ‐unsaturated acids containing an inverted allylic group. Starting from cyclic n‐membered α‐vinyl‐substituted ethers, lactones with n+4‐membered rings are formed. A very facile synthesis of the naturally occurring macrolides (±)‐phoracantholide I (10) and (±)‐phoracantholide J (11) illustrates the synthetic utility of this new ‘ketene’ Claisen rearrangement.
Nucleosid‐Synthesen in der Imidazolreihe
Authors: Wyss Pierre C. , Fischer Ulf 
Published: December 2004

Synthesis of Imidazole NucleosidesThe acid‐catalyzed fusion of dimethyl imidazole‐4,5‐dicarboxylate (7) with 1‐O‐acetyl‐2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranose (6) provided dimethyl 1‐(2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranosyl)imidazole‐4,5‐dicarboxylate (11) as the major product together with some β‐anomer (13). The β‐anomer (11) was obtained as the only product when the trimethylsilyl derivative (9) of 7 was condensed with 6 in the presence of stannic chloride. Nucleoside 11 was treated with ammonia, and various primary amines to provide 1‐β‐D‐ribofuranosylimidazole‐4, 5‐dicarbox‐amide (5) and N, N'‐disubstitued dicarboxamides (18‐26) respectively. The synthesis of 1‐β‐(33) and 1‐β‐D‐arabinofuranosylimidazole‐4,5‐dicarboxamide (34), is also described. The conformation of 5, as studied by 1H‐and 13C‐NMR.‐spectroscopy, was shown to be very similar to that of adenosine.The oxidation of the 2′,3′‐O′‐isopropylidene derivative (15) of 5 with potassium permanganate or chromic oxide, followed by deprotection, or the direct oxidation of 5 with oxygen in the presence of platinum catalyst, led to the corresponding 5′‐carboxylic acid 36. This was further converted into esters (37 and 38) and amides (39‐42).Treatment of some nucleosides with fuming nitric acid in oleum at ‐ 30° yielded the nitric acid esters 43‐51. Beside the nitration of their sugar residues, one of the imidazolecarboxamide functions in nucleosides 46‐51 and both N‐methyl‐carboxamide functions in 44 were nitrated. Finally, reaction of the N, N'‐dimethyl‐N, N'‐dinitrodicarboxamide 44 with alkyl‐ und aralkylamines, afforded the N, N'‐dialkyl‐and N, N'‐diaralkyldicarboxamides 52‐56.
(cis‐6‐Methyltetrahydropyran‐2‐yl)acetic Acid, a Novel Compound from Civet (Viverra civetta)
Authors: Maurer Bruno , Grieder Alfred , Thommen Walter 
Published: December 2004

AbstractThe isolation and synthesis of (cis‐6‐methyltetrahydropyran‐2‐yl)acetic acid (1a), a novel compound from civet (Viverra civetta), are reported.
Déconjugaison d'énones dérivées de sucres Communication préliminaire
Authors: Tronchet Jean M. J. , Gentile Bernard , Nguyen‐Xuan Tho 
Published: December 2004

Deconjugation of sugars enones. Preliminary CommunicationBranched‐chain sugar enones 1 and 2 (R = Ac) deconjugated toposelectively (only the E isomers reacting) to 3. The same phenomenon was noted in the case of Z‐4 which gave E‐5. The kinetic parameters of these reactions favored a concerted mechanism, i.e. a [1, 5]‐sigmatropic shift.
Specifically (π → π*)‐Induced Cyclohexenone Reactions 6‐Benzylbicyclo [4.4.0]dec‐1‐en‐3‐ones
Authors: Mariaca Raul , Schaffner Kurt 
Published: December 2004

Abstract6‐Benzylbicyclo [4.4.0]dec‐1‐en‐3‐one (9) and the 2‐methyl homologue (10) underwent a (γ → α )‐1, 3‐benzyl shift to the β,γ‐unsaturated ketones 21 and 22, respectively, when excited in the π π* absorption band. The quantum yield was ca. 0.1 at 254 nm for the formation of both products in alkane solvents. These reactions occur specifically from the S2(π, π*) state in competition with its decay to the S1(n, π*) and T states. The triplet reaction of 9, initiated by n → π* irradiation and by sensitization, was a double‐bond shift to 20, whereas no identifiable product was observed from 10 under these conditions. Direct and acetone‐sensitized irradiations of 21 and 22 resulted in oxadi‐π‐methane rearrangements to mixtures of syn‐ and anti‐30 and syn‐ and anti‐31, respectively.