bluuebunny/crossref_metadata_2025_split huggingface dataset:
Résonance magnétique nucléaire du noyau 14N par Transformée de Fourier
Authors: Kintzinger Jean‐Pierre , Lehn Jean‐Marie 
Published: December 2004

Abstract14N‐NMR. measurements using the Fourier Transform technique are presented and compared to C. W. experiments. The F. T. technique is especially advantageous for relaxation time measurements. However, since 14N‐nuclei may have widely different relaxation times, it is often not possible to have optimal gain in sensitivity (as compared to C. W. measurements) in a single F. T. experiment for different 14N‐nuclei contained in the same sample. Different experiments have to be performed, optimizing the spectrometer parameters for each 14N‐resonance of appreciably different linewidth.The technique is applied to three different problems. 14N‐relaxation in symmetrical ammonium salts is shown to arise from reorientation of the water dipoles. The use of a double spin‐probe, 13C‐14N, allows the determination of the electric field gradients in cyclic ammonium salts. The electronic distribution is especially distorted from tetrahedral symmetry in the highly strained N, N‐dimethyl‐aziridinium cation. Finally, electric and dynamic effects in ion pairing may be studied as shown on the case of tetrabutylammonium iodide in water and in benzene.
«Template»‐Reaktionen I. Herstellung von tricyclischen und tetracyclischen Metallkomplexen aus aromatischen 1,2‐Diaminen und 1,3‐Dicarbonylverbindungen
Authors: L'Eplattenier François A. , Pugin André 
Published: December 2004

AbstractThe condensation of 1,2‐phenylenediamine 1 and 1,3‐dicarbonyl compounds 2 in the presence of a divalent metal ion such as Ni2+, Cu2+, Co2+, yields the tricyclic 4 or tetracyclic complexes 5. The yields of these one step template reactions is very high in a large number of examples with differently substituted diamines 1 and 1,3‐dicarbonyls 2.
Synthesis of 1,4,9,12‐Tetraoxa‐dispiro[4.2.4.2] tetradeca‐6, 13‐diene via an Electrochemical Path
Authors: Margaretha Paul , Tissot Paul 
Published: December 2004

AbstractThe electrolysis of hydroquinone bis(2′‐hydroxyethyl)ether (3) in alkaline methanol gives 8‐[(2′‐hydroxy)ethoxy]‐8‐methoxy‐1, 4‐dioxa‐spiro[4.5]deca‐6, 9‐diene (4) which is converted to the title compound by treatment with traces of p‐toluenesulfonic acid in ether at 0° in 50% overall yield.
A Quantitative Assessment of „Through‐space”︁ and „Through‐bond”︁ Interactions. Application to Semi‐empirical SCF Models
Authors: Heilbronner Edgar , Schmelzer Andreas 
Published: December 2004

AbstractThe scheme of ‘through‐space’ and ‘through‐bond’ interaction of (semi)localized orbitals, originally proposed by Hoffmann, is reexamined in terms of SCF many‐electron treatments. It is shown that the two types of interaction can be characterized by examining the corresponding off‐diagonal matrix elements of the Hartree‐Fock matrices of the localized or the symmetry adapted localized orbitals and of the partially diagonalized Hartree‐Fock matrices referring to ‘precanonical orbitals’.The procedure outlined is applied to three practical examples using the semiempirical many‐electron treatments SPINDO, MINDO/2 and CNDO/2:

A reassessment of ‘through‐space’ and ‘through‐bond’ interaction in norbornadiene indicates, that the latter type of interaction is also of importance for the orbital based mainly on the antisymmetric combination of the localized x‐orbitals. The differences in the predictions derived from the three models are critically examined.
The competition between ‘through‐space’ and ‘through‐bond’ interaction in the series of bicyclic dienes from norbornadiene to bicyclo[4.2.2]‐dcca‐7,9‐diene and in cyclohexa‐1,4‐diene, i. e. their dependence on the dihedral angle UI is reexamined. It is found that the rationalization for the orbital crossing near ω = 130° deduccd from PE. spectroscopic data can not be as simple as originally suggested and that the relay’ orbitals responsible for ‘through‐bond interaction affecting both the symmetric and the antisymmetric combination of the π‐orbitals extend over the whole CC‐σ‐system of the six membered ring.
‘Through‐bond’ interaction of the two lone pair orbitals in 1,4‐diazabicyclo[2.2.2]octane is found to be large for their symmetric and the antisymmetric linear combination.
The analysis quoted, draws attention to some of the dangers involved in using semiempirical treatments for the interpretation of PE. data in terms of Koopmans′ theorem, without due caution.
Phthalimido‐nitren I. Bleitetraacetat‐Oxydation von N‐Aminophthalimid in inerten Lösungsmitteln. Bildung und Eigenschaften von trans‐1,4‐Bisphthaloyl‐2‐tetrazen
Authors: Hoesch Lienhard , Dreiding André S. 
Published: December 2004

AbstractLead tetraacetate oxidation of N‐aminophthalimide (11) in inert solvents gives as major products phthalimide (15) or trans‐1,4‐bisphthaloyl‐2‐tetrazene (12), the former (15) on slow, the latter (12) on fast addition of the oxidizing agent. As by‐products are found: (a) in the presence of acetic acid: N‐acetylamino‐phthalimide (14), and (b) in its absence (especially at higher temperatures): benzocyclobutenedione (13) along with N‐phthalimido‐phthalimide (16) as well as traces of phthalic anhydride (17).The tetrazene 12 and phthalimide (15) are considered to be formed by oxidation and fragmentation, respectively, of the intermediate 1,4‐bisphthaloyl‐tetrazane (18). Phthalimido‐nitrene (22), or its conjugated acid 23, is postulated to be the species which initiates the major reactions, namely: (a) addition to the educt 11 to give the tetrazane 18 and (b) fragmentation with loss of N2 to give the dione 13. The minor by‐products 16 and 17 may be the result of cross‐amidation of 11 with 15 and rearrangement‐oxidation via phthalazine‐1,4‐dione (30), respectively.The structure of the tetraacyltetrazene 12 follows from its properties, among others a comparison of its UV. spectrum with that of the known 1,4‐dimethoxycarbonyl‐1,4‐dimethyl‐2‐tetrazene (32). Methanolysis of 12 affords 1,4‐di‐(o‐methoxycarbonyl‐benzoyl)‐2‐tetrazene (33). The diacyltetrazene 33 is converted to methyl N‐methoxycarbonyl‐anthranilate (36), N2 and phthalimide (15) on thermolysis, or to methyl N‐acetylphthalamate (35), methyl N, N′‐carbonyldianthranilate (37) and methyl N‐acetyl‐anthranilate (38) on acetylation in pyridine. The intermediate in these reactions, leading to 36, 37 and 38, probably is o‐methoxycarbonyl‐phenylisocyanate (34), itself the result of a Curtius‐type rearrangement. Acetolysis of the tetrazene 12 gives phthalimide (15), N2 and N‐carboxyanthranilic anhydride (42) by a mechanism analogous to that of the methanolysis of 12.In the preparation of 1,4‐dimethoxycarbonyl‐1,4‐dimethyl‐2‐tetrazene (32), required for the above mentioned comparison, by zinc reduction of methyl N‐methyl‐N‐nitro‐carbamate (43), followed by bromine oxidation of methyl N‐amino‐N‐methylcarbamate (44), a deamination of 43 to methyl N‐methyl‐carbamate (45) was observed both in the reductive and in the oxidative step. Both formations of 45 can be formulated via a nitrene and a tetrazane, namely via 47 and 48.
Die Alkaloide von Gabunia eglandulosa STAPF 155. Mitteilung über Alkaloide
Authors: Agwada Vincent C. , Morita Yutaka , Renner Ulrich , Hesse Manfred , Schmid Hans 
Published: December 2004

AbstractFrom the root bark of the Apocynaceae Gabunia eglandulosa STAPE seven indole alkaloids were isolated. Besides the known indole alkaloids (−)‐isovoacangine (1), (−)‐coronaridine (2), voacamine (3), vobasine (4), and perivine (5), two new bases (−)‐19‐hydroxy‐isovoacangine (6) and 19‐hydroxy‐coronaridine (15) were isolated. Compound 6 was obtained by oxidation of isovoacangine with iodine. Similar oxidation reactions with voacangine (12) were studied.
Biosynthesis of juvenile hormone in the cecropia moth. labelling pattern from 1‐[14C]‐propionate through degradation to single carbon atom derivatives
Authors: Peter Martin G. , Dahm Karl H. 
Published: December 2004

AbstractIn the adult made cecropia moth, 1‐[14C]‐propionate is incorporated specifically into juvenile hormone I (1). By chemical degradation it was found that only C(7) and C(11) are labelled, each carbon atom bearing 50% of the radioactivity originally present in JH‐I. It is concluded that propionate serves as a precursor of homomevalonate, which in turn is a precursor for JH‐I. Application of 2‐[14C]‐propionate and 3‐[14C]‐propionate leads to extensive randomization of the label. Apparently propionate is metabolized such that C(2) and C(3) can be reused as smaller fragments–probably acetate–while C(1) is either highly diluted or removed from the propionate in a metabolically inactive form.
Sur la synthèse du pollinastanol à partir du cycloartanol
Authors: Bekaert Alain , Devys Michel , Barbier Michel 
Published: December 2004

AbstractThe partial synthesis of pollinastanol (14) from cycloartanol (3) is reported. The transformation proceeds through the methylenic intermediate 12; the ring enlargement with cyanogen azide affords pollinastanone (13) further reduced to 14, The 4‐keto isomer of pollinastanone (17) as well as a series of 5‐β isomeric compounds are also described.
Identification of the Bitter Principle of Cocoa
Authors: Pickenhagen Wilhelm , Dietrich Paul , Keil Borivoij , Polonsky Judith , Nouaille Françoise , Lederer Edgar 
Published: December 2004

AbstractThe following diketopiperazines have been identified in roasted cocoa: Cyclo(‐Pro‐Leu‐), Cyclo(‐Val‐Phe‐), Cyclo(‐Pro‐Phe‐), Cyclo(‐Pro‐Gly‐), Cyclo(‐Ala‐Val‐), Cyclo(‐Ala‐Gly‐), Cyclo(‐Ala‐Phe‐), Cyclo(‐Phe‐Gly‐), Cyclo(‐Pro‐Asn‐), Cyclo(‐Asn‐Phe‐).The typical bitterness of cocoa is due to an interaction of the purine theobromine (2) and diketopiperazines, which are formed during the roasting of the coca beans.
Selektive Synthesen mit Organometallen IV: Gezielte Hydroxylierung von Allylstellungen
Authors: Rauchschwalbe Günter , Schlosser Manfred 
Published: December 2004

AbstractConversion of alkenes into 2‐alken‐1‐ols of predictable constitution and configuration can be readily achieved via alkenylpotassium and boronic ester intermediates.
Stereoselektive Synthese von optisch aktivem Vincamin
Authors: Pfäffli Paul , Oppolzer Wolfgang , Wenger Roland , Hauth Hartmut 
Published: December 2004

AbstractVincamine (13) was prepared from the aldehyde 8 in 5 steps using methyl dimethyl‐phosphono‐methoxy‐acetate as a synthon for the pyruvic ester residue. A method to convert apovincamine (12) into vincamine (13) has hen worked out. Optically active 8 was synthesized from ethyl‐malonaldehydic acid ethyl ester in 9 steps including optical revolution of the acid intermediate 3 by means of salt formation with L‐(+)‐pseudoephedrine. The two diastereomeric salts were distinguishable by NMR. in carbontetrachloride.
13C‐NMR.‐Spectroscopy of the Trichothecane Derivatives Verrucarol, Verrucarins A and B and Roridins A, D and H Verrucarins and Roridins, 33rd Communication [1]
Authors: Breitenstein Werner , Tamm Christoph 
Published: December 2004

AbstractPartial decoupling experiments permitted assignment of carbon magnetic resonance spectra of verrucarins A (1) and B (4), of roridin A (2), D (5), and H (6), and of verrucarol (9). In this connection new verrucarol derivatives were prepared and are described.
Darstellung und Konfiguration von Tricarbonylchromat‐Anionen mit SnCl3− und GeCl3− als Liganden
Authors: Herber Brigitte , Scotti Mario , Werner Helmut 
Published: December 2004

AbstractB3N3Me6Cr(CO)3 reacts with [AsPh4] [SnCl3] and [AsPh4] [GeCl3] in tetrahydrofuran to give [AsPh4]3[Cr(CO)3(SnCl3)3] and [AsPh4]3[Cr(CO)3(GeCl3)3], respectively. According to IR. and 13C‐NMR.‐data, the tricarbonylate anions possess a meridional configuration. The donor‐acceptor properties of SnCl3− and GeCl3− in the anions [Cr(CO)3(ECl3)3]3− (E = Sn, Ge) are very similar. A similar synthesis of [AsPh4]3[Cr(CO)3(SnF3)3] was not successful.
Effect of Substituents and of Wavelength of Irradiation on the Photo‐Fries‐Rearrangement of Enol‐Esters Preliminary Communication
Authors: Veierov Dan , Bercovici Tuvia , Fischer Ernst , Mazur Yehuda , Yogev Amnon 
Published: December 2004

AbstractEnol‐esters 1a‐1e undergo clean Photo‐Fries‐rearrangements without side reactions. With anthroyl derivatives the reaction is observed only at 254 nm, not at 366 nm.
The Radical Anion of trans‐10b, 10c‐Dihydropyrene
Authors: Elschenbroich Christoph , Gerson Fabian , Boekelheide Virgil 
Published: December 2004

AbstractThe radical anion of trans‐10b, 10c‐dihydropyrene (V), which is formed upon reduction of the isomeric [2.2]metacyclophane‐1,9‐diene (III) with solvated electrons, has been identified by its ESR.‐spectrum. The large coupling constant (19.1 Gauss), due to the two equivalent β‐protons in the alkyl bridge, gives evidence of an important hyperfine interaction between the σ‐MO's of the C(sp3)‐H bonds and the singly occupied π‐MO of the fourteen‐membered perimeter. This finding supports the assumption that the unexpected energy sequence of the lowest antibonding perimeter MO's in the dihydropyrene V and its 10b, 10c‐dimethyl derivative (VI) is determined by hyperconjugation rather than by the inductive effect of the alkyl bridge.When the solution of V○ in 1,2‐dimethyoxyethane (DME) is brought in contact with an alkali metal mirror, an immediate conversion of VΦ into the radical anion of pyrene (IV) occurs. The anion IVΦ also results from reduction of [2.2.2](1,3,5)cyclophane‐1,9,17‐triene (VIII) with potassium in DME, whereas the radical anions of 4,5,9,10‐tetrahydropyrene (II) and its 2,7‐dimethyl‐derivative (IX) are obtained by corresponding reactions of [2.2]metacyclophane (I) and [2.2.2](1,3,5)cyclophane (VII), respectively.
Contribution à l'étude de la mésomérie, X Simplification du calcul des éléments du déterminant séculaire par voie graphique Système formé d'un atome à quatre électrons et de n atomes à un électron chacun
Authors: Klement Oscar , Rigamonti Flaviano , Portmann Josef 
Published: December 2004

AbstractOn indique une méthode graphique simplifiant considérablement, dans le cadre de la méthode de mésomérie, le calcul des éléments du déterminant séculaire et par conséquent celui de l'énergie et de la répartition électronique. Les régles de calcul présentées sont valables pour un système formé d'un atome à quatre électrons et d'un nombre quelconque d'atomes à un électron chacun. En outre, il a été possible de réunir dans un seul ensemble les règles valables pour des systèmes d'un atome à 1, 2, 3 ou 4 électrons et de n atomes à un électron chacun.
Horminon, Taxochinon und weitere Royleanone aus 2 abessinischen Plectranthus‐Spezies (Labiatae)
Authors: Hensch Marcel , Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

Horminone, taxoquinone and other royleanones, obtained from two Abyssinian Plectranthus species (Labiatae).From the coloured glands on the leaves of two botanically unclassified Plectranthus sp. from Abyssinia, a series of royleanones has been isolated, namely royleanone (1) and 6,7‐dehydroroyleanone (2) from one species, and 6,7‐dehydroroyleanone, horminone (3), taxoquinone (4), 6β, 7α‐dihydroxyroyleanone (5), 7α‐acetoxy‐6β‐hydroxyroyleanone (6) and 7‐oxoroyleanone (7) respectively, from the other.
Säurekatalysierte Umlagerung von 7‐Hydroxy‐royleanon in ein 20(10→9) abeo‐Abietan‐Derivat und zwei Phenalenone
Authors: Hensch Marcel , Eugster Conrad Hans , Weber Hans‐Peter 
Published: December 2004

Acid‐catalyzed rearrangement of 7‐hydroxyroyleanone into a 20(10→9) abeo‐abietane derivative and two phenalenonesShort treatment of either horminone (1b), taxoquinone (1a), 6,7‐dehydroroyleanone (3) or 6β‐hydroxyroyleanone (1c) with 80% H2SO4 at 0° leads to a mixture of rearranged products. Two of the structures, determined by X‐ray‐cristallography, were found to be (9R, 10R)‐20(10→9)‐abeo‐12‐hydroxy‐5,7, 12‐abietatriene‐11,14‐dione (4) and 9‐isopropyl‐2,2,5‐trimethyl‐8H‐phenaleno[1,9‐bc]furan‐8‐one (5), and the third compound, isolated in very small amounts, has been provisionally identified as 3‐hydroxy‐9‐isopropyl‐2,2,5‐trimethyl‐8H‐phenaleno[1,9‐bc]furan‐8‐one (6) from the spectroscopic data.
Phthalimido‐nitren II. cis‐ und trans‐2,3‐Dimethyl‐1‐phthalimido‐aziridin. Synthese und Solvolysen
Authors: Hoesch Lienhard , Dreiding André S. 
Published: December 2004

Phthalimido‐nitrene IITeil I, siehe [1].

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cis‐ and trans‐2,3‐Dimethyl‐1‐phthalimido‐aziridine. Synthesis and Solvolytic Reactions

Teilweise vorgetragen in der Versammlung der Schweizerischen Chemischen Gesellschaft in St. Gallen am 4. Oktober 1969 und in vorläufiger Form veröffentlicht [2].
The addition of phthalimido‐nitrene (2), generated by lead tetraacetate oxidation of N‐amino‐phthalimide (1), to cis‐ and trans‐2‐butene gave stereospecifically cis‐ 3 and trans‐2,3‐dimethyl‐1‐phthalimido‐aziridine 4 respectively. Acetolysis converted the cis‐aziridine 3 slowly and the trans‐aziridine 4 rapidly, again stereospecifically, to threo‐7 and erythro‐O‐acetoxy‐3‐phthalimidoamino‐2‐butanol (8) respectively. The velocity relation of the two acetolyses is considered to be due to a difference in steric release on the way to the transition state of a SN2‐type reaction. Acid‐catalysis converted 7 to threo‐11 and 8 to erythro‐3‐(N‐acetyl‐N‐phthalimido‐amino)‐2‐butanol (12). The equilibria in this acetyl migration between oxygen and nitrogen (threo‐pair 7:11 = 65:35; erythro‐pair 8:12 = 91:9) are rationalized on steric grounds.The hydrolyses of 3 and 4 were equally stereospecific, leading to threo‐9 and erythro‐3‐phthalimidoamino‐2‐butanol (10) respectively. These two compounds 9 and 10 were also available by reacting phthalimide (23) respectively with threo‐17 and erythro‐3‐hydrazino‐2‐butanol (18) which in turn were prepared by hydrazinolysis of cis‐13 and trans‐2,3‐dimethyloxirane (14) respectively. A N‐phthaloyl to N,N′‐phthaloyl rearrangement (possibly base catalyzed) was observed, which converted 9 and 10 to threo‐19 and erythro‐(N,N′‐phthaloyl)‐3‐hydrazino‐2‐butanol (20) respectively.It is of interest that in the compounds discussed above the NMR.‐coupling (in deuteriotrichloromethane) between H‐‐C(2) and HC(3) is larger (J = 6–9 Hz) in the threo‐series than in the erythro‐series (J = 2–3 Hz). This shows a depopulation of the conformers 21a and 22a with anti‐periplanar arrangement of the hetero substituents, rationalizable by intramolecular hydrogen bonds in the conformers 21b ⇄ 21c and 22b ⇄ 22c. This is confirmed by the observation that the stereomeric pairs 19/20 and 9/10 show equal coupling between HC(2) and HC(3) (J = 8/8 and 6.6/7 respectively) when the NMR.‐spectra were measured in hexadeuterio‐dimethylsulfoxide, a solvent which can compete with intramolecular hydrogen bonding.An attempt is made to rationalize why the NMR.‐chemical shifts in deuteriotrichloromethane of HC(2) and HC(3) in the threo‐series lie at higher fields than those in the erythro‐series, the exception again being the 19/20, pair, measured in hexadeuterio‐dimethylsulfoxide.
Strukturbestimmung von O‐Methylazafrinmethylester durch 13C‐NMR.‐Spektroskopie
Authors: Vögeli Ulrich , Eschenmoser Walter , Eugster Conrad Hans 
Published: December 2004

Structure Determination of Azafrin Methyl Ester 5‐O‐Monomethyl Ether by 13C‐NMR.‐Specta.The structure of the monomethyl ether (2) of azafrin methyl ester (1) was determined by a partial analysis of the 13C‐NMR.‐spectra. Assignments of quaternary carbon atoms and methyl groups in the cyclohexane ring were achieved using vicinal 13C‐, 1H‐spin coupling. Substituent effects on methyl and methylene carbon atoms in 2 are discussed with respect to the conformation of the methoxy group. The spectra prove C(5)OH as the site of methylation. Therefore C(5)OH is less hindered than C(6)OH.
Synthèse et configuration absolue des énantiomères du Vér apamil
Authors: Ramuz Henri 
Published: December 2004

Synthesis and Absolute Confifguration of the Enantiomers of Verapamil.Starting from the acids IV‐(+) and IV‐(−), a synthesis of the enantiomers I‐(+) and I‐(−) of the coronary vasodilator Verapamil is described and their absolute configuration determined through a chemical filiation with the acid XII‐(S)‐(+).
Oxetane vs. cyclobutane formation in the photocycloaddition of enones to olefins. The photoaddition of 6‐fluoro‐4,4‐dimethyl‐2‐cyclohexenone to 2,3‐dimethyl‐2‐butene. Preliminary communication
Authors: Desobry Vincent , Margaretha Paul 
Published: December 2004

Abstractn‐π* Excitation of 6‐fluoro‐4,4‐dimethyl‐2‐cyclohexenone in the presence of 2,3‐dimethyl‐2‐butene leads selectively to the formation of the corresponding oxetane. The factors which influence the oxetane vs. cyclobutane formation ratio in photoadditions of cyclic enones to olefins are discussed.
Physico‐Chemical Properties of Deuteriated Compounds. 1st Communication. The molar volume of n‐heptane
Authors: Öz Hami , Gäumann Tino 
Published: December 2004

AbstractThe molar volumes of mixtures of perdeuteriated and protiated heptane have been measured between ‐10° and 40° and expressed as a second order polynomial of the weight fraction. The difference in molar volumes of about 0.4 ml/mol decreases with temperature. The possibility of using the density measurement to determine the degree of deuteriation of mixtures of partially deuteriated heptanes was examined. The percent deuteriation calculated by this method deviates systematically from the true values.
Über Reaktionen oxygenierter Kobalt(II)‐Chelate. VI. Präparative Darstellung von diastereoisomeren Tetrakis(äthylendiamin)‐μ‐peroxo‐μ‐hydroxodikobalt(III)‐perchloraten
Authors: Zehnder Margareta , Fallab Silvio 
Published: December 2004

On Reactions of oxygenated Cobalt(II) Chelates. VI. Preparation of diastereoisomeric tetrakis(ethylenediamine)‐μ‐peroxo‐μl‐hydroxo‐dicobalt(III) PerchloratesOxygenation of Co(en)22+ leads to a mixture of two isomeric forms of [(en)2Co(O2, OH)‐Co(en)2] (ClO4)3 · H2O from which the less soluble meso form can be readily crystallized. Further crystallization from the mother liquor yields the racemate ΔΔ/ΔΔ. The pure racemate may be obtained by either of the following methods: (a) By ligand exchange starting from mono bridged [(NH3)5CoO2Co(NH3)5] (NO3)4 or from doubly bridged [(SCN) (NH3)3Co(O2, OH)Co(NH3)3(SCN)] SCN · 2H2O. (b) By reaction of cis‐[Co(en)2(OH2)2]3+ with H2O2. Reaction (b) proceeds via an intermediate cis‐[Co(en)2(OOH) (OH2)] (ClO4)2 · H2O which at higher pH reacts with [Co(en)2(OH) (OH2)]2+ to yield the desired doubly bridged ΔΔ/ΔΔ tetrakis(ethylenediamine)‐μ‐peroxo‐μ‐hydroxodikobalt(III)‐perchlorate.
Über die selektive katalytische Reduktion von substituierten Anilinen zu substituierten Cyclohexylaminen und von Benzol‐ bzw. Phenyl‐alkan‐sulfonsäuren zu Cyclohexan‐ bzw. Cyclohexylalkan‐sulfonsäuren
Authors: Egli Robert , Eugster Conrad Hans 
Published: December 2004

AbstractBei Verwendung von Rh‐Alox‐Katalysatoren lassen sich p‐Aminophenyl‐2‐hydroxyäthyl‐äther unter sorgfältig definierten Bedingungen ohne starke Hydrogenolyse zu cis‐/trans‐(4‐Aminocyclohexyl)‐(2‐hydroxyäthyl)‐äthern reduzieren; durch selektive Reduktion erhält man 4‐Benzyl‐cyclohexylamin aus 4‐Benzylanilin sowie 1‐(4‐Aminocyclohexyl)‐2‐phenyl‐äthan aus 1‐(4‐Aminophenyl)‐2‐phenyl‐äthan.Rh‐ und Ru‐Katalysatoren sind imstande, die bisher als nicht hydrierbar geltenden Methyl‐, Amino‐ und Hydroxy‐benzolsulfonsäuren quantitativ in die Methyl‐, Amino‐ und Hydroxy‐cyclohexansulfonsäuren überzuführen. Die Hydrierparameter werden ausführlich diskutiert.Wie sich aus 13C‐NMR.‐Daten herleiten lässt, entstehen bevorzugt die cis‐Stereoisomeren. Die 4‐Methyl‐cyclohexansulfonsäure liegt bei Raumtemperatur zu > 90% in der Konformation mit axialer CH3‐ und äquatorialer SO3Θ‐Gruppe vor (als Na‐Salz in D2O gemessen).