bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and determination of the enantiomeric purity of (R)‐ and (S)‐2,3‐Dihydroxy‐3‐methylbutyl p‐Toluensulfonate
Authors: Schrötter Eberhard , Hauser Andre , Hamann Hans‐Jürgen , Schick Hans , Schönecker Bruno 
Published: December 2004

Abstract(R)‐ and (S)‐2,3‐dihydroxy‐3‐methylbutyl p‐toluenesulfonate, used as building blocks for vitamine D3 metabolites and carotenoids, respectively, were resynthesized since differing melting points and optical rotations are reported in the literature. The given data of the (S)‐enantiomer could be corrected. A method for the determination of the enantiomeric purity was elaborated using the influence of a chiral lanthanide shift reagent on the 1H‐n.m.r. spectra of these compounds. By this way it was shown that both compounds exhibit an enantiomeric excess of more than 94%. The (S)‐enantiomer was synthesized according to an improved synthetic scheme starting from L‐serine.
Quantum chemical calculations of the molecular geometries and electronic absorption spectra of simple Cumulenes and Aza‐cumulenium Cations
Authors: Mehlhorn Achim 
Published: December 2004

AbstractThe molecular geometries in the electronic states S0and T1, heats of formation, singlet‐triplet splitting and transition energies of cumulenes and 1‐ and 2‐aza‐cumulenium cations up to chain lengths of 11 C‐atoms have been investigated by means of MINDO/3, CNDO/S and a modified PPP procedure. As far as experimental data are available their agreement with the theoretical results is satisfactory. This enables the molecular structure, the spectral behaviour and the colour of cumulated chains to be extrapolated up to chains of 20 C‐atoms. The properties of the cumulenes studied are compared with those of polyenes and polymethines and attempts were made to integrate cumulated chains within these classes of unsaturated chain molecules.
MO‐LCAO‐Berechnungen an schwefelhaltigen π‐Elektronensystemen. XLIX. Tetramethinverbrückte Oxalsäurederivate – neue farbige Pigmente von indigoider Struktur
Authors: Beckert R. , Fabian J. 
Published: December 2004

MO‐LCAO Calculations on Sulfur‐containing π‐Electron Systems. XLIX. Tetramethine Bridged Derivatives of the Oxalic Acid – Novel Coloured Pigments of Indigoid StructureWhereas thioamides react with the oxalylchloride to Δ2‐thiazoline‐4,5‐diones 1, which are precursors of the versatile thioacylisocyanate 2 synthons, the analogous reaction between thioamides and oxalyl‐bis(arylimidchlorides) completely fails. In the case of aliphatic thioamides the intermediate 2‐methyl‐Δ2‐thiazoline‐4,5‐diimides 3 undergo oxydative dimerization. The poorly soluble products are tetramethine bridged heteroanalogous oxalates 4 or isomers. The u.v./vis spectra of the blue compounds are in favour with structure 4 rather than with structure 6. This conclusion has been drawn from the results of Pariser‐Parr‐Pople(PPP) type calculations. According to the calculated position of the colour band of the pigments and of different molecular subunits, and the correspondence of their electronic states involved in the excitation, the dye molecules can be thought as consisting of two symmetrically crossed polymethine chains. This structural feature is inherent to the H indigo chromophore.
MO‐LCAO‐Berechnungen an schwefelhaltigen π‐Elektronensystemen. L. Synthese und UV/S‐spektrale Eigenschaften von 1H‐Perimidinthioncarbonsäurederivaten
Authors: Thiel W. , Fabian J. , Friebe B. 
Published: December 2004

MO‐LCAO Calculations on Sulfur‐containing π‐Electron Systems. L. Synthesis and UV/VIS Spectral Properties of Derivatives of 1H‐Perimidine‐2‐thioncarbonic AcidEsters of the 1H‐perimidine‐2‐dithiocarbonic acid are easily accessible from 1.8‐diamino‐naphthalene and chloroacetyl chloride and subsequent thiolation of the reaction product under mild conditions and alkylation. The dithioesters react with aliphatic and aromatic amines to form thioamides. Both the resulting dithioesters and thioamides are clearly distinguished by their colour from the vast majority of known derivatives of thioncarbonic acids. While dithioesters and thioamides are generally red and yellow, respectively, in solution the corresponding derivatives of the 1H‐perimidine are blue and red, respectively. The detailed examination of the experimental data has revealed that the colour determining longest wavelength absorption bands are due to the π→π* rather than to the n→π* transitions. Due to the efficient mixing of the lowest energy locally excited (LE) state of the heterocyclic moiety and the lowest energy perimidine‐to‐substituent charge transfer (CT) state the low‐intensity longwavelength π→π* transition of perimidine undergoes a pronounced red shift by acceptor substituents of high electron affinity in 2‐position. This interpretation of the deep colour of the 1H‐perimidine‐2‐thiocarbonic acid is in harmony with substituent effects and fully born out by Pariser‐Parr‐Pople(PPP) type calculations completed by additional analyses of electronic state (Baba‐Suzuki‐Takemura analysis) and electronic transitions (Ohta‐Kuroda‐Kunii analysis).
Exo‐ and endohormones. IX. Syntheses of Monounsaturated Sex Pheromones of Lepidoptera via 3‐alkyn‐1‐ols
Authors: Pop Lidia , Oprean I. , Barabas A. , Hodosan F. 
Published: December 2004

Abstract3‐Alkyn‐1‐ols as intermediate synthons in the preparation of some Lepidoteran sex pheromones were utilized. Characteristic fragmentations reflecting the position of the triple bond were found in the mass spectra of 3‐alkyn‐1‐ols and alkyn‐1‐yl acetates in contrast to 1‐tert.‐butoxy‐alkynes. A partial isomerization of 1‐tosyloxy‐3‐(Z)‐octene to 1‐bromo‐3‐(E)‐octene within the reaction with NaBr in DMF was noticed by GC and 13C‐n.m.r., for which a mecanism involving homoconjugation in an intermediate non‐classical carbonium ion was suggested.
Versuche zur Synthese sterisch gehinderter Thiazylarene und deren Beziehung zu Arylsulfenylnitrenen
Authors: Mayer R. , Decker D. , Bleisch S. , Domschke G. 
Published: December 2004

Attempts to Synthesize Sterically Hindered Thiazyl Arenes and Their Relationship to Arylsulfenyl NitrenesUp till now all attempts to synthesize organic thiazyl compounds in substance failed. Stabilization leads to the corresponding disulfide 2, the thioaminyl radical 7 and the sulphur diimide 8. Formally thiazyl compounds 1 and sulfenyl nitrenes 1 were resonance structures. Via sulfenyl nitrenes 1 the formation of 2, 7, 8 can be discussed. An in situ preparation of sulfenyl nitrene 1a via the sulfenyl chloride 5a, synthesized by chlorination of the disulfide 2a, and the sulfenyl azide 6a is described in detail. 1a can also be prepared from the sulfenyl amide 4a by oxidation. The structures of the radicals 7a–f and 12f are discussed.
1H‐NMR‐Untersuchung von Pyrido[1,2‐a]1,3,5‐triazinen: Through bond‐ und through space‐Effekte ringintegrierter Carbonyl‐, Thiocarbonyl‐ und Iminocarbonylgruppen
Authors: Bödeker J. , Köckritz A. , Köppel H. 
Published: December 2004

1H‐N.M.R. Investigation of Pyrido [1.2‐a]1.3.5‐triazines: Through Bond and Through Space Effects of Ringintegrated Carbonyl, Thiocarbonyl, and Iminocarbonyl GroupsFrom the 1H‐n.m.r. spectra of pyrido[1.2‐a]1.3.5‐triazines 1a–i the characteristic data δ(H6), δ(H8), and J(H6, H7) are submitted. The ring‐integrated carbonyl groups in the position 2 (CX) show a deshielding electronic through bond effect on the protons H6 and H8 in the order of CNPh < CO < CS. On the other hand, the relative through space effect of these groups is in the order CO < CNPh < CS; this relation was determined by their deshielding influence in the position 4 (CY) on the peristanding proton H6. Finally the synthesis and the dissoziation behaviour of the new pyridotriazines 1d and 1h are described.
Exo‐ und Endohormone. XI. Synthese von monoolefinischen Sexualpheromonen der Lepidopteren über die α‐Diketone
Authors: Oprean I. , Ciupe Hilke , Gansca Lucia , Hodosan F. 
Published: December 2004

Exo‐ and Endohormones. XI. Synthesis of Monounsaturated Sex Pheromones of Lepitopetra via α‐Diketonesα‐Diketones (5), prepared starting either with cyanohydrines (1) or with N,N‐diethyl oxamate (6), were converted via the dihydrazones (11) into acetylenes (12). Replacement of the protecting group by the acetate group and partial stereoselective reduction of the triple bond led finally to the title compounds.
The aldol reaction of substituted cyclopentane carbaldehydes with 2‐heptanone. A novel approach to the construction of the alkyl side chain of prostaglandins
Authors: Mahrwald Rainer , Schick Hans , Schwarz Sigfrid 
Published: December 2004

AbstractThe aldol reaction of suitably substituted cyclopentane carbaldehydes (1a–c, 4) with 2‐heptanone affords β‐hydroxy ketones (2a–c, 5) in yields up to 60%. These aldolization products can be dehydrated to known prostaglandin intermediates. Due to the difficulty to convert β,δ‐dihydroxy ketones selectively into α,β‐unsaturated δ‐hydroxy ketones this reaction sequence for the construction of the (E)‐3‐oxooct‐1‐enyl side chain of prostaglandins seems to be especially advantageous for the synthesis of 11‐deoxy‐prostaglandins.
Zur Alkylierung und Acylierung von 5‐Hydrazino‐1,2,3,4‐thiatriazolderivaten
Authors: Graubaum Heinz , Seeboth Helmuth 
Published: December 2004

On Alkylation and Acylation of 5‐Hydrazino‐1,2,3,4‐thiatriazole Derivatives5‐Hydrazino‐1,2,3,4‐thiatriazole reacts with oxo carboxylic acids to give highly unstable 5‐carboxyalkylidene‐hydrazino‐1,2,3,4‐thiatriazoles (2). The more stable 5‐alkylidenehydrazino‐1,2,3,4‐thiatriazoles (3) may be alkylated; the thiatriazole system is retained. On action of activated nitriles or isocyanates 1,2,4‐thiadiazole (6) or 1,2,4‐thiadiazoline derivatives (7) are formed with nitrogen evolution. At temperatures above 40°C, the described thiatriazoles decomposed to give undefinable components.
β‐Fur‐2‐yl‐α‐halogenacrylonitrile. VIII. Konformationsuntersuchungen an substituierten β‐Fur‐2‐yl‐acrylonitrilen
Authors: Hauser A. , Jähnisch K. , Kuban R. J. 
Published: December 2004

β‐Fur‐2‐yl‐β‐halogenacrylonitriles. VIII. Investigations of the Conformation of Substituted β‐Fur‐2‐yl‐acrylonitrilesX‐ray analysis, n.m.r.‐investigations in the presence of Eu(FOD)3 and NOE‐measurement indicate, that the E‐isomer of β‐substituted β‐fur‐2‐yl‐acrylonitriles exist in the s‐cis conformation, whereas the E‐isomer of the α‐substituted β‐fur‐2‐yl‐acrylonitriles prefer the s‐trans‐conformation. The influence of the configuration and conformation on the chemical shift of the H‐3‐furan protons is discussed.
Synthese von bipolaren Ionenaustauscherharzen
Authors: Wolf F. , Eckert S. , Schwachula G. , Sabrowski E. 
Published: December 2004

Synthesis of Bipolar Ion Exchange ResinsSyntheses of weakly acid/strongly basic and weakly acid/weakly basic bipolar ion exchange resins with varying acid and basic capacities via subsequent introduction of the exchange active groups in suitable crosslinked skeletal polymers are described.Methylacrylate‐styrene‐divinylbenzene polymers of varying composition which can be quantitatively chloromethylated and subsequently fully aminated (trimethylamine) and partially saponified in one process step were used as starting polymers for weakly acid/strongly basic resins. The reverse route saponification of the ester groups first, followed by chloromethylation of the aromatic parts of the matrix and animation turned out to the possible, if at all, only for bipolar resins of strongly predominant basic character. The capacity parameters can be controlled through the composition of the matrix.Polymethylacrylates crosslinked with divinylbenzene served as polymer basis of the weakly acid/weakly basic bipolar ion exchange resins. The functionalization was achieved by partial aminolysis with polyamines (dimethylaminopropylamine, ethylenediamine, diethylenetriamine) and saponification with lyes. The number of basic and acid groups which can be introduced is governed primarily by the conditions of the aminolysis. The capacity parameters are controllable within a broad range by the procedures.
Electronic Structure of Indandiones
Authors: Tyutyulkov N. , Tasseva M. , Georgiev E. 
Published: December 2004

AbstractIt is shown that the anions of the enolate forms of 1, 2‐ and 1, 3‐indandiones have antiaromatic character. This conclusion is reached after studying the geometry, the electron density distribution and the energy spectrum of the molecules.The anion of the 1,2‐indandione enolate form is unstable because of strong electron‐vibronic interaction.
Anodic oxidation of 3‐amino‐5‐(pyrid‐4‐yl)‐1, 2‐dihydropyrid‐2‐one (amrinone)
Authors: Hagen V. , Klauschenz E. , Pragst F. 
Published: December 2004

AbstractThe anodic behavior of the cardiotonic drug 3‐amino‐5‐(pyrid‐4‐yl)‐1,2‐dihydropyrid‐2‐one 1 and of 6 compounds with similar structure was investigated at platinum and vitreous carbon electrodes in acetonitrile and in aqueous medium. Caused by the 3‐amino group 1 is oxidized at a relatively small oxidation potential in an irreversible two‐electron process. Depending on the addition of a strong base or a strong acid the oxidation potential vs. SCE in acetonitrile is −0.08 V (anion), +0.66 V (neutral compound), +0.93 V (monocation) or +1.15 V (dication). In H2O a strong decrease of the oxidation potential with increasing pH was found as a reason for the sensitivity of 1 against oxygen in alkaline solution. The anodic oxidation of 3‐dimethylamino‐5‐(pyrid‐4‐yl)‐1, 2‐dihydro‐pyrid‐2‐one 3 in 0.1 m H2SO4 leads to 5‐(pyrid‐4‐yl)‐piperidine‐2,3,6‐trione 9a or 5‐(pyrid‐4‐yl)‐piperidine‐2,3,4‐trione 9b, which is also the oxidation product of 1 at small concentration. At high concentration of 1 coupling reactions at the 3‐amino‐group lead to dimeric products, which could not be identified.
Characterization of Microemulsions
Authors: Sowada Rudolf , Hauthal Hermann G. , Grossklaus Simone 
Published: December 2004

AbstractMicroemulsions have been characterized by determining water uptake capacity as well as paraffin oil uptake capacity by nephelometric titration. The term “Hydrophile‐Lipophile Index” (abbreviated HLK) for the ratio water uptake capacity to oil uptake capacity has been proposed for the characterization of microemulsions. It has been shown that both water uptake capacity WA and oil uptake capacity 0A are temperature‐dependent quantities. The temperature
coefficients d WA/d T as well as d OA/d T may be: > 0; = 0; < 0. Based on these findings microemulsion systems of any composition, any origin or any application purpose is classified into nine categories.
EPR‐spektroskopische Charakterisierung der Assoziation von Cu(II)‐Komplexen vinyloger Amide
Authors: Ewert Uwe , Freyer Wolfgang 
Published: December 2004

EPR‐Spectroscopic Characterization of Assoziating Cu(II)‐complexes of Vinylogic AmidesThe e.s.r. spectra of glassy solutions of the Cu(II)‐complexes with different enaminone‐ligands were measured in dependence on substituents and solvent polarity.CuCu distance and spatial angle α are calculated using the model of SMITH and PILBROW. In methylcylohexane only dimers could be detected. Two types of dimeric compounds were observed for which an interplane distance of r = 0.4 nm was calculated.In dimeric Cu‐complexes of 4‐anilinomethylen‐δ2‐pyrazolin‐5‐ones the CuCu axis is perpendicular (α = 0°), in dimeric Cu‐complexes of anilinomethylenpentan‐2,4‐diones the CuCu‐axis is inclined (α = 35°).
Zur Reaktion von Dicyclopentadiendiepoxid mit Acrylsäure
Authors: Heublein Günther , Burckhardt Astrid 
Published: December 2004

On the Reaction of Dicyclopentadiene Diepoxide with Acrylic AcidThe esterification of dicyclopentadiene diepoxide as a bifunctional epoxide with acrylic acid was investigated. The influence of solvent polarity, reaction temperature and the catalytic system used are discussed. It was found, that the reaction rate increased with increasing solvent polarity. By using tertiary amines as catalysts, only a small catalytic effect was observed. On the contrary, a good catalytic effect was achieved with Lewis‐acids. By means of FeCl3, a vinylester containing epoxide groups and CC‐double‐bonds is obtained, which polymerizes via various mechanisms.
Kinetischer H/D‐Isotopeneffekt der Photooxidation von 3,5‐Dimethyl‐1,1‐dioxo‐2‐(p‐tolyl)‐1,2‐thiazin durch Singulettsauerstoff
Authors: Fanghänel E. , Bode B. , Bedemann K.‐H. , Radeglia R. 
Published: December 2004

Kinetic H/D Isotope Effect of the Photooxidation of 3,5‐Dimethyl‐1,1‐dioxo‐2‐(p‐tolyl)‐1,2‐thiazine by Singlet OxygenThe hydrogen atoms of the thiazine ring and of the methyl groups of 3,5‐dimethyl‐1,1‐dioxo‐2‐(p‐tolyl)‐1,2‐thiazine 1a can be exchanged by deuterium in basic or acidic deutero methanol (CH3OD). In CD3OD/D2SO4 the rate of the H/D‐exchange of the different protons of 1a was determined by 1H‐n.m.r. spectroscopy.A kinetic isotope effect of 1.5–1.8 was determined from the rate of the oxygen consumption and also by using a competitive method. The results are in accordance with an “ene” reaction of 1a with singlet oxygen.
Chinolinanaloge Chalkone: Wittig‐Synthese, 13C‐NMR‐Spektren und Bestimmung von σ‐Konstanten für die 2‐, 3 und 4‐Position des Chinolins
Authors: Bödeker J. , Fieblinger D. , Radeglia R. 
Published: December 2004

Quinolineanalogous Chalcones: Wittig Synthesis, 13C‐N.M.R. Spectra and Estimation of σ‐Constants for the 2‐, 3‐ and 4‐Position of QuinolineThe Wittig type reaction of the quinolinealdehydes 2a—c with benzoylmethylentriphenylphosphorane (1) gives stereoselectively the E‐configurated quinolineanalogous chalcones 3a—c. These compounds react with methyl iodide to the N‐methyl‐quinolinium salts 4a—c. The complete 13C‐n.m.r. analysis of 3a—c is reported. From the chemical shift of the Cα‐signals and on the basis of a Hammett relationship σ‐constants were calculated for the 2‐, 3‐ and 4‐position of quinoline. These values are compared with those from kinetic measurements; the observed deviations are chiefly attributed to the extent of the resonance interaction in 3a—c.
Vibronic Spectral Behaviour of Molecules: Theoretical study on the vibrational structure of 9‐phenyl anthracene S1S0 absorption and fluorescence
Authors: Gustav K. 
Published: December 2004

AbstractUnderlying the completely‐optimized S0 and S1 molecular geometries of 9‐phenylanthracene, the vibronic ‘line’ spectra of the S0S1 absorption and fluorescence have been calculated within the Condon approximation. On this basis the corresponding theoretical spectrum contours as obtained by superposition of individual Gaussian line width functions are presented. For the spectroscopic peaks an analysis of the vibronic levels is given. The theory/experiment comparison of the respective vibrationally structured spectra of 9‐phenyl‐anthracene turns out to be satisfactory. It confirms likewise the geometric structure data calculated for both electronic states.
Spaltung von 1,2,4‐Thiadiazol‐3‐onen mit Triphenylphosphan: Triphenylphosphonio‐thioimidazolate und ihre Folgereaktionen
Authors: Tittelbach Franz , Martin Dieter 
Published: December 2004

Fission of 1,2,4‐Thiadiazol‐3‐ones by Triphenylphosphane: gewidinet Triphenylphosphonio Thioimidazolates and Their Consecutive ReactionsTreatment of benzimidazo[1,2‐d][1,2,4]thiadiazol‐3(2H)‐ones (1) and imidazo[1,2‐d]‐[1,2,4]thiadiazol‐3(2H)‐ones (17) with triphenylphosphan leads to the liberation of isocyanate and the formation of triphenylphosphonio‐thiobenzimidazolat (4) and triphenylphosphonio‐thioimidazolat (18), respectively. 2,4‐Diphenyl‐5‐phenylimino‐1,2,4‐thiadiazol‐3‐one (23) is desulfurized with Ph3P and decomposed into phenyl isocyanate and diphenylcarbodiimide whereas the N‐unsubstituted imino‐thiadiazol‐3‐one (25) is attacked at the exocyclic imino group by Ph3P to give the N‐phosphoranylidene thiourea (26). The structure of 4 can be rationalized as a dynamic system between polar and apolar valence isomeres. Reactions of 1 and 17 with cyanates, isocyanates, carbon disulfide, acetic anhydride, amines, benzyl chloride, grignard compounds, and CH acidic compounds are described.
Action of Grignard Reagents on 6‐Arylpyridazin‐3(2H)‐thiones
Authors: Fekry Ismail M. , Kaddah A. M. , Elkafrawy A. F. , Sayed Fekria S. , El‐Sawy O. M. 
Published: December 2004

Abstract6‐Arylpyridazin‐3(2H)‐thiones (1a—c) react with Grignard reagents by 1,4‐addition to give either 4‐substituted 6‐aryl‐4,5‐dihydropyridazin‐3(2H)‐thiones (2a—c) or their dehydrogenated products, namely 4‐substituted 6‐arylpyridazin‐3(2H)‐thiones (3d—k). The reaction of Grignard reagents with 6‐aryl‐4‐methylpyridazin‐3(2H)‐thiones (3d—f) proceeds also by 1,4‐addition yielding 4,4‐disubstituted 6‐aryl‐4,5‐dihydropyridazin‐3(2H)‐thiones (5). Structural assignments are based on analytical and spectral data and also on the synthesis of authentic samples in some cases.
The “normalizing factor” for the tomato mutant chloronerva. XXX. Synthesis of 3,4‐Seconicotianamine
Authors: Ripperger H. 
Published: December 2004

Abstract3,4‐Seconicotianamine (7) was synthesized by stepwise reductive alkylation of (S)‐N‐methylalanine ethyl ester (3) with ethyl (S)‐4‐oxo‐2‐(trifluoroacetylamino)butanoate (4). 3,4‐Seconicotianamine showed biological activity with regard to the phenotypical normalization of the tomato mutant chloronerva, but to a lesser degree than nicotianamine (1).
Nucleophile Substitutionen an Bischlornitrosoverbindungen. IV. Sulfonylaminooxime als Extraktionsmittel für Kupfer(II)
Authors: Beger J. , Neumann R. , Gloe K. , Mühl P. 
Published: December 2004

Nucleophilic Substitutions with Bischloronitroso Compounds. IV. Sulfonylaminooximes as Extracting Agents for Copper(II)New vicinal sulfonylaminooximes 5a–5v are synthesized from bischloronitroso compounds 1 or 2‐chlorooximes 2 and sulfonamides 4 under alkaline conditions. In several cases oligomeric products 6 result instead of 5. 2‐Sulfonylaminobenzophenoneoximes 8a–g are also prepared from 2‐aminobenzophenones and sulfonyl chlorides and subsequent reaction with hydroxylamine. The pH0,5 values for the extraction of copper‐(II)‐ions into a chloroformic solution are between 2,8 and 4. Compounds 8 are comparably weaker extragents then oximes 5.
Alkylierung und Umalkylierung von Aromaten an Alumosilicaten
Authors: Vogt F. , Wendlandt K.‐P. , Isakov Ja. I. , Isakova T. A. , Minačev Ch. M. 
Published: December 2004

Alkylation and Transalkylation of Aromatics on AlumosilicatesThe alkylation of toluene (benzene) with methanol and the isomerization of metaxylene on alumina‐silica and modified zeolites (HNaY, HM, HZSM‐5) are acid‐catalyzed proceed via a same intermediate. Except for the samples HZSM‐5, the alkylation of toluene (benzene) can be explained by activity — selectivity — correlations.The referential diffusion of para‐xylene in the channels of zeolithe ZSM‐5 leads to a high product selectivity in alkylation and transalkylation reactions. Suggesting the supposition of a triangular reaction scheme.
The improved Synthesis of 8‐Methylene‐des‐AB‐cholestan‐9‐one
Authors: Morzycki Jacek W. , Rodewald Wladyslaw J. , Jurek Jaroslaw 
Published: December 2004

AbstractAn improved synthesis of the title compound 6 is described. The starting cholesterol was transformed into 3β‐methoxy‐5β‐methyl‐19‐nor‐9,10‐secocholestane‐6,9,10‐trione (6E)‐monooxime derivative (2b). Its fragmentation under acidic conditions afforded 2‐cyano‐4‐methoxy‐2‐methylcyclohexanone (8) and 8‐methylene‐des‐AB‐cholestan‐9‐one (6). The mechanisms of this reaction and the isomerization of the latter compound to 8‐methyl‐des‐AB‐cholest‐8(14)‐en‐9‐one (7) are discussed.