bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Unified Interpretation of Kinetic Data on the Acid‐Induced Cleavage and of Product‐Analysis Data on Spontaneous Cleavage of the Mono‐ol Cation μ‐Hydroxo‐bis[pentaamminecobalt(III)] ([(NH3)5CoOHCo(NH3)5]5+)
Authors: Rotzinger François P. , Marty Werner 
Published: December 2004

AbstractRecent work on the spontaneous (= acid‐independent) cleavage of the mono‐ol cation, i.e.

in Cl−/ClO and NO/ClO mixed‐electrolyte media has established (by analysis of anion‐competition experiments) the existence of reactive ion pairs of the mono‐ol cation with Cl− and NO. Their existence must be allowed for in the analysis of the rate data for the acid‐induced cleavage (pH 0–1) of the mono‐ol cation in these mixed‐electrolyte media. Thus, previous data for acidic Cl−/ClO media have been re‐interpreted in this work, and new data for NO/ClO media have been analyzed in the same sense. This analysis removes an apparent discrepancy in the orders of magnitude of ion aggregate stability constants between the mono‐ol and similar binuclear cations.
Gas‐Phase Basicities of Furan Compounds. The Role of Alkyl Substitution on Proton Affinity and on the Site of Protonation
Authors: Houriet Raymond , Rolli Eric , Bouchoux Guy , Hoppilliard Yannick 
Published: December 2004

AbstractThe gas‐phase protonation of alkyl‐substituted furan compounds is investigated in equilibrium proton‐transfer reactions conducted in an ion cyclotron resonance (ICR) spectrometer. From the effects of substituents on the stability of protonated species, it is concluded that protonation of the majority of these systems occurs specifically on the C(α)‐atom to form carbenium ions. Parallel MO calculations performed on different structures of the products reinforce the experimental conclusions and provide energy values for the less stable structures. The solution reactivity of these compounds towards electrophilic agents and NMR spectra of protonated species obtained in strong acidic media have been investigated.
Enantioselective Syntheses and Absolute Configurations of Viridiene and Aucantene, Two Constitutents of Algae Pheromone Bouquets
Authors: Boland Wilhelm , Niedermeyer Uwe , Jaenicke Lothar , Görisch Helmut 
Published: December 2004

AbstractViridiene ((+)‐6; (+)‐(3R,4S)‐3‐((1Z)‐1,3‐butadienyl)‐4‐vinylcyclopentene) and aucantene ((+)‐18; (+)‐(4R,5R)‐4‐((1E)‐1‐propenyl)‐5‐vinylcyclohexene) are constituents of the pheromone bouquets of several brown algae species. Key synthons to the title compounds are optically active γ‐lactones with known or experimentally determined absolute configurations. Horse liver alcohol dehydrogenase, which catalyses the oxidation of meso‐ and racemic non‐meso diols to chiral lactones, and pig‐liver esterase, which catalyzes the saponification of meso‐diesters to chiral half‐esters, were utilized for the asymmetric synthesis of such precursors. The racemic non‐meso diol rac‐1 is converted to the two stereoisomeric γ‐lactones (+)‐2 and (+)‐3 which are readily separated. meso‐Diol 12 is oxidized to the chiral γ‐lactone (−)‐11. Its enantiomer (+)‐11 is obtained by enantioselective saponification of the meso‐diester 9 with pig‐liver esterase. Appropriately designed syntheses lead from these chiral intermediates to both enantiomers (+)‐ and (−)‐6 of viridiene and (+)‐ and (−)‐18 of aucantene. In addition, kinetically controlled reduction of the racemic aldehydes rac‐5a and rac‐15 with horse liver alcohol dehydrogenase offers a convenient alternative to the enantioselective preparation of the enantiomers of the two hydrocarbons 6 and 18. Chromatography of 6 on triacetylated cellulose as a stationary chiral phase confirms the enantiospecificity of the synthetic routes designed.
Face Selectivity of the Diels‐Alder Additions of Sulfur‐Substituted Dienes and Tetraenes Grafted onto 7‐Oxabicyclo[2.2.1]heptanes
Authors: Tornare Jean‐Marc , Vogel Pierre , Pinkerton A. Alan , Schwarzenbach Dieter 
Published: December 2004

AbstractStereoselective synthesis of 2‐methylidene‐3‐[(Z)‐(2‐nitrophenylsulfenyl)methylidene]‐7‐oxabicyclo[2.2.1]‐heptane (16), 1,4‐epoxy‐1,2,3,4‐tetrahydro‐5,8‐dimethoxy‐2‐methylidene‐3‐[(Z)‐(2‐nitrophenylsulfenyl)methylidene]anthracene (18), and 1,4‐epoxy‐1,2,3,4‐tetrahydro‐5,8‐dimethyoxy‐2‐methylidene‐3‐[(Z)‐(phenylsulfenyl)‐methylidene]anthracene (19) are presented. The Diels‐Alder additions of these S‐substituted dienes and those of 2,5‐dimethylidene‐3,6‐bis{[(Z)‐(2‐nitrophenyl)sulfenyl]methylidene}‐7‐oxabicyclo[2.2.1]heptane (17) have been found to be face selective and ‘ortho’ regiospecific. The face selectivity depends on the nature of the dienophile. It is exo‐face selective with bulky dienophiles such as ethylene‐tetracarbonitrile (TCNE) and 2‐nitro‐1‐butene and endo‐face selective with methyl vinyl ketone, methyl acrylate, and 3‐butyn‐2‐one. In the presence of a Lewis acid, the face selectivity of the Diels‐Alder reaction can be reversed. The addition of the first equivalent of a dienophile to tetraene 17 is at least 100 times faster than the addition of the second equivalent of the same dienophile to the corresponding mono‐adduct. The X‐ray structure of the crystalline bis‐adduct 43, a 7‐oxabicyclo[2.2.1]hepta‐2,5‐diene system annellated to two cyclohexene rings, resulting from the successive additions of methyl acrylate and methyl vinyl ketone to tetraene 17 is presented. Only one of the two endocyclic double bonds of the 7‐oxabicyclo[2.2.1]hepta‐2,5‐diene deviates from planarity, the substituents bending towards the endo face by 5.7°.
Aldonhydroximo‐lactones. Preparation and Determination of Configuration
Authors: Beer Dieter , Vasella Andrea 
Published: December 2004

AbstractThe syntheses of the unprotected, (Z)‐configurated hexon‐ and pentonhydroximo‐lactones 2a–12a by oxidation of D‐glucose, cellobiose, D‐galactose, D‐mannose, 2‐acetamido‐2‐deoxy‐D‐glucose, D‐ribose, and D‐arabinose oxime with MnO2, Hg(OAc)2, or O2 in the presence of Cu2Cl2/pyridine are described. An (E/Z)‐pair of protected hydroximo‐lactones 14 and 15 was obtained by oxidation of the diisopropylidene‐D‐mannose oxime 13 with MnO2. In CH2Cl2 solution, the minor (E)‐isomer 15 was slowly transformed into the major (Z)‐isomer 14. The structure assignments for 2a–12a are based upon IR and NMR data, the Beckmann rearrangement of 1 and 14, and the X‐ray structure analysis of 7a and 47. From the selectively deprotected hydroximo‐lactones 2c, 8c, and 9c, the urethanes 2d, 2f, 8d, and 9d were prepared. (E/Z)‐mixtures of the amino phosphates 27/28, 29/30, and 31/32 were obtained from the bromonitroso ethers 16, 19, and 17 and NaPO(OEt)2. The configuration of the bromonitroso ethers 18 and 19 were assigned on the basis of their CD spectra and of their correlation with the corresponding bromonitro ethers 24 and 25. Factors influencing the configuration of the hydroximo‐lactones are briefly discussed.
The Synthesis and Protonation of 1,1‐Di(1‐pyrrolyl)alkenes
Authors: Schärer Jean‐Claude , Etienne Robert , Burger Ulrich 
Published: December 2004

AbstractIt is shown that lithiation of di(1‐pyrrolyl)methane (3) can be directed either towards the C(α) ring positions or to the central CH2 group, depending upon the solvent and the complexing agents chosen. Di(1‐pyrrolyl)‐methyllithium (6), resulting from CH2 deprotonation, is intercepted by aldehydes and converted to the title alkenes in a few straightforward steps. Protonation of 1,1‐di(1‐pyrrolyl)ethylene (10) is found to occur under kinetic control at the terminal olefinic position. In HBF4. Me2O the resulting 5‐azionafulvene‐type ion 14 can be observed by low‐temperature NMR spectroscopy. In FSO3H, however, protonation is directed under thermodynamic control to both pyrrole rings. The resulting symmetrical dication 13 persists even at room temperature.
Structure and Stereochemistry of New Sesquiterpene Esters from Echinacea purpurea (L.) MOENCH. (Preliminary communication)
Authors: Bauer Rudolf F. X. , Khan Ikhlas A. , Lotter Hermann , Wagner Hildebert , Wray Victor 
Published: December 2004

AbstractThe structure elucidation of four new constituents from the roots of Echinacea purpurea is described. They are shown to be cinnamoyl esters of sesquiterpene alcohols with a germacrane or a guaiane skeleton. First pharmacological results indicate immunological activities.
Synthesis of xanthone O‐glycosides. Part III. Synthesis of 1‐ and 8‐O‐β‐D‐glycosides of 5‐O‐methyl‐ and de‐O‐methylbellidifolin
Authors: Vermes Barbara , Seligmann Otto , Wagner Hildebert 
Published: December 2004

AbstractThe unambiguous synthesis of three naturally occurring and biologically active xanthone 1‐O and 8‐O‐β‐D‐glucosides of 5‐O‐methyl‐ and de‐O‐methylbellidifolin (2–4) was accomplished. The protected xanthone aglycones having only a single reactive OH group were prepared by selective benzylation, methylation, and debenzoylation reactions. An unexpected stability of the 1‐MeO group towards demethylation was observed.
Die toxischen und sedierend wirkenden Bufadienolide von Kalanchoedaigremontiana HAMETet PERR
Authors: Wagner Hildebert , Lotter Hermann , Fischer Manfred 
Published: December 2004

The Toxic and Sedative Bufadienolides of Kalanchoe daigremontiana HAMET et PERR.From the toxic Crassulacee Kalanchoe daigremontiana five biosynthetically related bufadienolides have been isolated and structurally elucidated by X‐ray and 1H‐ and 13C‐NMR spectroscopy. The compounds were identified as bersaldegenin 1,3,5‐orthoacetate (2), bersaldegenin 1‐acetate (4), bersaldegenin 3‐acetate (3), 1β,3β,5,11α,14‐pentahydroxy‐12,19‐dioxo‐5β,14β‐bufa‐20,22‐dienolide 1,3,5‐orthoacetate ( = daigremontianin; 1), and 3β‐acetoxy‐1β,5,14‐trihydroxy‐5β,14β‐bufa‐20,22‐dienolide ( = daigredorigenin‐3‐acetate, 5). According to the pharmacological investigations, the two orthoacetates 1 and 2 comprise the positive inotropic, sedative, and toxic activity of the plant.
Enantioselective Synthesis of D‐erythro‐Sphingosine and of Ceramide
Authors: Julina Radomir , Herzig Thomas , Bernet Bruno , Vasella Andrea 
Published: December 2004

AbstractThe enynol 2 was transformed into D‐erythro‐sphingosine 11 (7 steps, 46%) and into ceramide 1 (8 steps, 41% overall yield). The key steps were the mono‐epoxidation of the enynol 5 (Ti(t‐BuO)4, (−)‐D‐diethyl tartrate, t‐BuOOH) to 6 (86%, ≥ 98% ee), the regioselective intramolecular opening of the oxirane 6 via the benzylurethane 7, and the reductive tranformation of the acetylene 9 into the oxazolidinone 10 (Li, EtNH2, 88%).
Herstellung von disubstituierten Maleinsäure‐anhydriden mit Hilfe von reaktiven 2‐Oxo‐3H‐imidazo[1,2‐a]pyridinium‐Verbindungen
Authors: Baumann Marcus E. , Bosshard Hans , Breitenstein Werner , Rist Günter 
Published: December 2004

Preparation of Disubstituted Maleic Anhydrides from Reactive 2‐Oxo‐3H‐imidazo[1,2‐a]pyridinium CompoundsA new useful method for the preparation of disubstituted maleic anhydrides, most of them bearing additional functional groups in the side chain, is described. The key step of the synthesis consists of the addition of 2‐oxo‐3H‐imidazo[1,2‐a]pyridinium compounds to a variety of different Michael acceptors.
Single‐Centre Model for the Active Site of α‐Chymotrypsin
Authors: Vorherr Thomas , Altmann Karl‐Heinz , Mutter Manfred 
Published: December 2004

AbstractThe polymer‐bound heptapeptide H‐Glu‐His‐Pro‐Gly‐Ser‐Gly‐PEGM was designed as a ‘single‐centre model’ for the active site of α‐chymotrypsin. The peptide was synthesized according to the general principles of the liquid‐phase method for peptide synthesis, and its conformational properties were investigated by CD and IR spectroscopy in solution and in the solid state. In harmony with empirical prediction codes, experimental and theoretical conformational considerations, the peptide adopts a β‐turn conformation stabilized by H‐bonds involving the side chains of Glu, His, and Ser. The development of a H‐bonded system similar to the active site of α‐chymotrypsin leads to implications with respect to a possible catalytic activity of the model peptide.
1,4‐Dithiafulvene aus der Umsetzung von 4,4‐disubstituierten 1,3‐Thiazol‐5(4H)‐thionen mit Acetylenderivaten
Authors: Jenny Christjohannes , Heimgartner Heinz 
Published: December 2004

1,4‐Dithiafulvenes, Products of the Reaction of 4,4‐Disubstituted 1,3‐Thiazol‐5(4H)‐thiones and Acetylenic CompoundsOn heating in toluene, 4,4‐disubstituted 1,3‐thiazol‐5(4H)‐thiones 1 and acetylenecarboxylates or acetylenecarbonitriles 2 undergo a cyclosubstitution reaction to yield 2‐methylidene‐1,3‐dithiol derivatives 3 (1,4‐dithiafulvenes) and a nitrile. Further heating of 3a and 3b in the presence of excess 2a leads to the isomeric 2,3‐dihydrothiophene‐2‐thiones 4a and 4b, respectively. The benzodithiafulvene 14 has been formed in a similar reaction from 1a and in situ generate benzyne.
Photochemical reactions. 147th Communication. Further investigation of the photochemistry of 5,6‐epoxy‐5,6‐dihydro‐β‐ionone: Product formation via a carbonyl‐ylide intermediate
Authors: O'Sullivan Anthony , Frei Bruno , Jeger Oskar 
Published: December 2004

AbstractOn π,π*‐excitation of the epoxyenone (E)‐1 (λ = 254 nm, MeCN), in addition to the previously isolated compounds 2–9, the new products 10–12, derived from the ylide intermediate c were isolated. Further evidence for the ylide c was obtained by the rapid racemization of the optically active epoxyenone (−)‐(E)‐1.
Cacospongione A, cacospongienone A, and cacospongienone B, new C21 difuran terpenoids from the marine sponge Cacospongiascalaris SCHMIDT of the Côte d' Azur
Authors: Guella Graziano , Amade Philippe , Pietra Francesco 
Published: December 2004

AbstractThe sponge Cacospongia scalaris (family Thorectidae), collected at the Cap de Nice (Cǒte d'Azur), is shown to contain a series of truncated, linear C21 difuran terpenoids comprising the known sponge products furospongin‐1 ((+)‐1), furospongin‐2 (2), and dihydrofurospongin‐2 ((−)‐(E)‐3), besides the new products cacospongione A ((−)‐4), cacospongienone A ((−)‐(Z)‐6), and cacospongienone B ((−)‐(E)‐6), whose absolute configurations have been assigned by chemical correlations with (+)‐1. Possibly, one of the two cacospongienones is an artifact, as these two terpenoids interconvert on standing. This is the first finding of linear C21 difuran terpenoids, which are typical of the Spongiidae, in a member of the family Thorectidae.
Preparation via Diastereoselective Hydrogenation, Absolute Conformation and Configuration of Exogeneous Anabolic Zeranol ((3S, 7R)‐3,4,5,6,7,8,9,10,11,12‐Decahydro‐7,14,16‐trihydroxy‐3‐methy‐1H‐2‐benzoxacyclotetradecin‐1‐one)
Authors: Snatzke Günther , Angeli Cristina , Decorte Enio , Moimas Flavio , Kojié‐Prodié Biserka , Ruz̆ić‐Toroš Z̆iva , S̆unjić Vitomir 
Published: December 2004

AbstractHydrogenation of the ketone group in di‐O‐benzylderivative (8) of the known macrocyclic lactone zeralenone (7) using a novel chiral borane complex 3. BH3, prepared in situ, proceeded at lower temperatures with moderate diastereoselectivity (∼40%, d. e. at −60°). Unsaturated diastereomers 9 and 10 were separated, and 9 converted into zeranol (11), a known anabolic agent. Restricted conformational mobility at lower temperatures is assumed for the intermediate 8 on the basis of the temperature‐dependent CD spectra of its acetyl congeners 18 and 19. X‐Ray structure analysis of 7‐O‐acetylderivative (13) of 11 revealed the (R)‐configuration at C(7). Two crystallographically independent H2O molecules are involved in the H‐bonds, one of them (O(21)) rises the helices of the molecules of 13 along b. Small positive torsional angle [C(16)‐]C(161)‐C(1) [=O] (+19.3°), transoid(E) conformation of the lactone group, and nearly achiral arrangement of the C(11)‐C(12) bond (torsional angle [C(11)‐]C(12)‐C(121)[C(161)] is −93°) are the main conformational features that differentiate the macrocylic RAL (resorcinic‐acid lactone) derivatives from the 6‐membered lactone derivative 20, studied earlier by CD. Consequently, the rules developed for the CD effects within conjugation band (around 270 nm), and n→π* band (around 255 nm) of the latter compound, cannot be applied the macrocyclic lactones.
Conformational Analysis of Endoperoxides Grafted onto Bicyclo[2.2.n]alkanes as a Test of the Rigidity of the Bicyclic Skeleton. Photo‐oxidation of [2.2.2] Hericene and 2,3,5,6‐Tetramethylidenebicyclo[2.2.n]alkanes
Authors: Birbaum Jean‐Luc , Vogel Pierre 
Published: December 2004

AbstractThe photo‐oxidation of [2.2.2]hericene (6) gave successively the endoperoxides 11 (9,10,11,12‐tetramethylidene‐4,5‐dioxatricyclo[6.2.2.02,7]dodec‐2(7)‐ene), the bis‐endoperoxide 16 (15,16‐dimethylidene‐4,5,11,12‐tetraoxatetracyclo[6.6.2.02,7.o9,14]hexadeca‐2(7),9(14)‐diene), and the tris‐endoperoxide 19 (4,5,11,12,17,18‐hexaoxapentacyclo[6.6.6.02,7.09,14.015,20]icosa‐2(7),9(14),15(20)‐triene). The endoperoxides 11, 16, and 19 were formed in the presence or in the absence of a dye sensitizer. The sensitized photo‐oxidations of 2,3,5,6‐tetramethylidenebicyclo[2.2.2]octane (4), 5,6,7,8‐tetramethylidenebicyclo[2.2.2]oct‐2‐ene (5), 2,3,5,6‐tetramethylidenebicyclo[2.2.1]‐heptane (7), and 2,3,5,6‐tetramethylidene‐7‐oxabicyclo[2.2.1]heptane (8) gave successively the corresponding mono‐endoperoxides 9, 10, 12, and 13 and the bis‐endoperoxides 14, 15, 17, and 18, respectively. Low‐temperature NMR spectra of the bis‐endoperoxides 14 and 16 indicated that their C2 and Cs conformers have the same stability. Similarly, there was no difference in the enthalpy of the D3 and C2 conformers of the tris‐endoperoxide 19. The following reactivity sequence was observed for the sensitized photo‐oxidations of 6–8 and 5,6‐dimethylidene‐7‐oxabicyclo[2.2.1]hept‐2‐ene (23): 6 + 1O2→11 > 7 + 1O2→12>8 + 1O2→13>23 + 1O2→24, a trend parallel with that reported for the ethylenetetracarbonitrile (TCNE) cycloadditions to the same polyenes. The rate‐constant ratios k1/k2 and k2/k3 for the three successive photo‐oxidations of [2.2.2]hericene (6) did not differ significantly from unity, in contrast with the Diels‐Alder additions of 6. Similarly, the rate‐constant ratios k1/k2 for the two successive photo‐oxidations of tetraenes 7 and 8 were significantly smaller than those reported for the successive TCNE cycloadditions to 7 to 8. The endoperoxide formations are not sensitive to the change in the exothermicity of the reactions but they are sensitive to the electronic properties (IP's) of the polyenes.
Aza‐2‐diènes‐1,3 3. Nouvelles voies d'accès à des amino‐2‐pyrazines substituées
Authors: Lang Mare , Schoeni Jean‐Paul , Pont Christiane , Fleury Jean‐Pierre 
Published: December 2004

2‐Aza‐1,3‐dienes. A New Approach to Substituted 2‐AminopyrazinesTreatment of enamines by tosylated isonitrosomalono derivatives gives access to 5‐dialkylamino‐1, 1‐dicyano 2‐aza‐1,3‐dienes (or 1‐methoxycarbonyl analogous) which are precursors of various regiospecific 5,6‐substituted 2‐amino‐3‐cyano (or methoxycarbonyl) pyrazines. Some examples of utilisation of these intermediates for synthesis of lumazines, pteridines, and other bicyclic skeletons are described.
Approaches to Synthetic Vaccines Design of Epitope‐Containing Amphiphilic Peptides Matching the Antigenic Structure in the Native Protein
Authors: Mutter Manfred , Altmann Karl‐Heinz , Müller Klaus , Vuilleumier StéPhane , Vorherr Thomas 
Published: December 2004

AbstractA general procedure for the design of synthetic vaccines with the retained conformational features of protein antigenic determinants is described. This new concept emerges from detailed studies on the relationship between primary sequence and secondary structure formation of synthetic peptides and takes advantage of the amphiphilic nature of epitope‐containing peptide segments in the native protein to accomplish structural modifications. These segments, for example amphiphilic helices or β‐sheets, are stabilized by the insertion of secondary structure‐inducing amino‐acid residues on the hydrophobic part of the peptide without affecting the spatial arrangement of functional residues on the hydrophilic side. The availability of amphiphilic peptides with tailor‐made conformational properties, e.g. helices, β‐sheets, and, moreover, assemblies of these blocks to structures of higher order (‘folding units’), allows the presentation and stabilization of continuous as well as discontinuous epitopes by this approach. This strategy is exemplified for the case of two discontinuous epitopes taken from lysozyme, which are matched to host molecules with adequate conformational features by the help of computer‐assisted molecular modelling. The implications of this new concept for the design of synthetic vaccines are discussed with special emphasis to the important role of peptide synthesis and chemical structure modification.
Aza‐2‐diènes‐1,3 4. Préparation et propriétés d'alkyl‐1‐pyrazone‐imines et de leurs isomères
Authors: Lang Marc , Lacroix Alain , Pont Christiane , Fleury Jean‐Pierre 
Published: December 2004

2‐Aza‐1,3‐dienes. Synthesis and Properties of 1‐Alkylpyrazone‐imines and their TautomersTreatment of 5‐dialkylamino‐1,1‐dicyano‐2‐aza‐1,3‐dienes (or their 1‐methoxycarbonyl analogoues) with primary amines gives substituted 1‐alkyl‐3‐cyano‐(or methoxycarbonyl‐)pyrazoneimines. Tautomeric behaviour, nucleophilic addition to imino function and spectroscopic data of these isomers are examined.
Desoxy‐nitrozucker. 13. Mitteilung. Herstellung ungeschützter und partiell geschützter 1‐Desoxy‐1‐nitro‐D‐aldosen sowie Röntgenstrukturanalysen einiger ihrer Vertreter
Authors: Beer Dieter , Bieri Jost H. , Macher Ingolf , Prewo Roland , Vasella Andrea 
Published: December 2004

Preparation of Unprotected and Partially Protected 1‐Deoxy‐1‐nitro‐D‐aldoses and Some Representative X‐Ray Structure AnalysesThe unprotected and partially protected 1‐deoxy‐1‐nitro derivatives of α‐and β‐D‐glucopyranose (see 15 and 14), β‐D‐mannopyranose (see 16), N‐acetyl‐β‐D‐glucosamine (see 17), β‐D‐galactofuranose (see 19), β‐D‐ribofuranose (see 20), α‐D‐arabinofuranose (see 21), 4,6‐O‐benzylidene‐β‐D‐glucose (see 40), N‐acetyl‐4,6‐O‐benzylidene‐β‐D‐glucosamine (see 41), and 4,6‐O‐benzylidene‐β‐D‐galactose (see 42) were prepared by ozonolysis of the corresponding nitrones which were obtained from the acid‐catalyzed reaction of p‐nitrobenzaldehyde with the hydroxylamine 4, the unprotected oximes 3 and 5–9 and the 4,6‐O‐benzylidene oximes 35–37, respectively (Schemes 1–3). The gluco‐ and manno‐nitrones 10 and 12 were isolated, and their ring size and their anomeric and (E/Z) configurations were determined by NMR spectroscopy and by their transformation into their corresponding nitro derivatives. The structure of the deoxynitroaldoses were determined by NMR spectroscopy, polarimetry, and, in the case of 14, 16, and 17, by formation of the 4,6‐O‐benzylidene (14→40) or 4,6‐O‐isopropylidene (16→43, 17→23) derivatives (Scheme 3). Acetylation of the nitroglucopyranose 14, the 2‐acetamido‐nitroglucopyranose 17, and the nitrogalactofuranose 19 gave the crystalline peracetylated nitroaldoses 22, 24, and 45, respectively (Scheme 4, Figs. 1 and 3); acetylation of the nitromannopyranose 16 gave the nitro‐arabino‐glycal 44 (Scheme 4). The structure of the peracetylated nitroglucopyranose 22, the nitroglucosamine 25, the nitrogalactofuranose 45, and the nitroribofuranose 20 were confirmed by X‐ray analysis (Figs. 1 4). In all cases, including the β‐D‐glucopyranose derivative 22, considerably shortening of the (endocyclic) C(1)‐O bond was observed. Base‐catalyzed anomerization of the β‐D‐configurated nitroglucopyranose 14, the nitromannopyranose 16, the benzylidene acetal 40 of nitroglucose, and the 2,3,4,6‐tetraacetylated glucosamine derivative 24 gave the corresponding nitro‐α‐D‐aldoses 15, 26, 47, and 25, respectively (Scheme 4).