bluuebunny/crossref_metadata_2025_split huggingface dataset:
Konformation und Circulardichroismus der Sesquiterpene vom Trichothecan‐Typ und deren makrocyclischen Estern
Authors: Snatzke G. , Tamm C. H. 
Published: December 2004

AbstractThe circular dichroism of keto derivatives with trichothecane skeleton and some of their rearrangement products has been measured. The sign (and sometimes even the magnitude) of all COTTON effects can be explained by applying the respective rules for the cyclohexanone, cyclopentanone, enone and ene‐ester chromophores. Thus conformations could also be determined in those cases which did not follow unambiguously from conformational analysis. The conformation of the muconic acid moiety of the macrocyclic ring of verrucarin A is the same in dioxane solution as in the crystalline state.
Darstellung und Charakterisierung einige Thiocyanat‐ und Selenocyanat‐Komplexe von Übergangsmetallen
Authors: Schmidtke Hans‐Herbert , Garthoff Dieter 
Published: December 2004

AbstractSome 6:1 thiocyanate complexes of FeIII, MoIII, RuIII, OsIII, IrIII and some 6:1 or 4:1 selenocyanate complexes of FeII, FeIII, MoIII, RhIII, PdII, PtII, and AuIII have been prepared as salts of large organic cations. The compounds are characterized by their infra‐red spectra and by conductance measurements. In particular the linkage property of the thiocyanate and selenocyanate ligand is discussed together with the consequences it has on the AHRLAND‐CHATT‐DAVIES‐PEARSON classification of the central ions.
Organische Phosphorverbindungen XXVIII. Die α‐Aminoalkylierung von elementarem weissem Phosphor. Eine einfache Methode zur Darstellung von tertiären Phosphinoxiden, Phosphinsäuren und Phosphonsäuren [1]
Authors: Maier Ludwig 
Published: December 2004

AbstractWhite phosphorus reacts with N‐hydroxymethyl‐dialkylamines to give mainly three products, i.e., tris(dialkylaminomethyl) phosphine oxides, bis(dialkylamino‐methyl) phosphinic acids, and dialkylaminomethyl phosphonic acids, according to the equation:

The yield of the various products depends mainly upon the ratio of the reactants, the pH, and the solvents used.
Pyrazines. 1re communication. I. Synthèse de méthyl‐2‐pyrazines alcoylées en 3, par condensation de l'éthylènediamine avec les dioxo‐2,3‐alcanes
Authors: Flament I. , Stoll M. 
Published: December 2004

AbstractThe synthesis of eight 2‐methyl 3‐alkyl pyrazines by catalytic dehydrogenation of condensation products of ethylenediamine with 2,3‐diketoalkanes is described.
Synthese funktionell abgewandelter Flavocoenzyme: 3‐Alkyl‐ und 2‐Alkylimino‐flavin‐mononucleotide und ‐flavin‐adenin‐dinucleotide. Studien in der Flavinreihe, 14. Mitteilung
Authors: Föry W. , Hemmerich P. 
Published: December 2004

AbstractFunctional derivatives of flavo‐coenzymes, altered in position 2 or 3, have been synthesized in order to check the coenzyme specificity of flavo‐apoproteins. Phosphorylation and phosphate separation methods have been adapted to the synthesis of 2‐imino‐,2‐thio‐ and 3‐alkyl‐flavin mono‐ and di‐nucleotides.
Über die strukturellen Probleme des Di‐cyclopentadienyl‐titans
Authors: Salzmann J.‐J. , Mosimann P. 
Published: December 2004

AbstractOn the basis of spectral and chemical evidence it is shown that bis(cyclopentadienyl)titanium is not a sandwich‐π‐type compound. The most probable structure in solution is that of a dimer containing metal‐metal bond and π‐and σ‐bonded cyclopentadienyl rings.
Über die Ringspannung in pentacyclischen Azofarbstoff‐Chrom(III)‐Komplexen
Authors: Schetty G. 
Published: December 2004

AbstractIn pentacyclic chromium‐azo dyestuff complexes in which two azo dyestuffs in a vertical position to each other are so linked that a metal‐containing hetero ring
magnified image
is formed, the number of members of this hetero ring was systematically increased. The alterations occurring in the electron spectra express the change in the position of the two azo dyestuff residues or the change in tension occurring in the hetero ring. When the number of ring atoms is sufficiently large, which in this series of compounds was 15 (n = 10), the electron spectrum is identical with that of the «open» form, i.e. with that of the corresponding 1:2 complex devoid of this particular ring. The position of the two azo dyestuff residues, therefore, must be identical in both complexes, and this is only possible when the adjoining ring is completely free from tension. The phenomenon of ring tension can, therefore, be visibly followed in these examples.
Die Koordinationstendenz des Murexid‐Ions
Authors: Geier G. 
Published: December 2004

AbstractThe stability constants of the murexide complexes with various metal ions were determined spectrophotometrically. The coordination tendencies of the tridentate ligands iminodiacetate, dipicolinate and murexide are compared. In terms of basicity and charge, the murexide complexes exhibit a stability which is remarkably high and most of all pronounced with A‐metal ions. The possible reason for this fact is discussed.
ψ‐Bufarenogin, ein neues Bufadienolid aus Ch'an Su und Umlagerungsprodukt des Arenobufagins sowie Bemerkung zur Konfiguration des Bufarenogins. Über Krötengifte 32. Mitteilung
Authors: Huber Kurt , Linde Horst , Meyer Kuno 
Published: December 2004

AbstractAus der chinesischen Krötengiftdroge Ch'an Su konnte ein bisher unbekanntes Bufogenin isoliert werden, das sich bei den chromatographischen Auftrennverfahren wie Bufarenogin verhält, weshalb wir es ψ‐Bufarenogin 5 nennen. −5 und Arenobufogin (3) gehen bei der vorsichtigen Dehydrierung in dasselbe 3,11,12‐Trioxobufadienolid über, unterscheiden sich somit lediglich in ihrer Ketolstruktur an C‐11/C‐12. Der aus der Acetylverbindung von 5 durch Abbau erhaltene Ätiansäure‐methylester 17 war mit den vier möglichen, bereits bekannten C‐11/C‐12‐Acetoxy‐ketonen der Ätiansäure‐Reihe nicht identisch. Auf Grund chemischer und vor allem spektroskopischer Befunde dürfte der aus 5 erhaltene Abbauester 17βH‐Konfiguration besitzen, die sich im Laufe des Abbaus durch Umlagerung ausgebildet hat. ψhyphen;Bufarenogin ist 3β, 12α,14‐Trihydroxy‐11‐oxo‐5β‐bufa‐20,22‐dienolid entsprechend Formel 5. Bufarenogin besitzt 12β‐Hydroxy‐11‐oxo‐Struktur; die Stereochemie an C‐17 ist noch nicht abgeklärt.
Zur Kenntnis der Benzylpenicilloinsäure
Authors: Schneider C. H. , De Weck A. L. 
Published: December 2004

AbstractThe molar penamaldate value of benzylpenicilloic acid and the influence of large amounts of benzylpenicillin on the estimation of penamaldate values and penamaldate stabilities of benzylpenicilloic acid and ε‐(benzylpenicilloyl‐α‐amido)‐caproic acid have been determined. The molar penamaldate values of purified benzylpenicilloate and of benzylpenicillin hydrolyzed in alkali were equal, indicating that benzylpenicillin upon alkaline hydrolysis is converted to penicilloic acid exclusively, with no side reactions occurring to any considerable degree. Benzylpenicilloate mutarotates in neutral solution as well as in alkali, the reaction being unaffected by metal ion complexing with ethylene diamine tetraacetate. ε‐(Benzylpenicilloyl‐α‐amido)‐caproate also mutarotates in alkali; no mutarotation occurs however in neutral solution. Different mechanisms of epimerisation have therefore to be considered for the mutarotations of penicilloates and of α‐amides of penicilloic acid respectively.
Löslichkeitsprodukte von Metalloxiden und ‐hydroxiden. 11. Mitteilung [1]. Die Löslichkeit von α‐GaO(OH) bei 60°C in perchlorsauren Lösungen konstanter Ionenstärke
Authors: Gamsjäger H. , Schindler P. 
Published: December 2004

AbstractThe solubility equilibrium of α‐GaO(OH) has been investigated at 60°C in solutions of perchloric acid having a constant ionic strength I = 3 m (Na, H)ClO4. The hydrogen ion concentration of the equilibrated solutions was measured with a glass electrode and the concentration of the dissolved GaIII was determined by chelometric titration. The experimental data can be explained by assuming the equilibrium

.
Trypsinhemmstoffe aus Ascaris lumbricoides var. suum I. Herstellung von reinen Trypsininhibitoren
Authors: Portmann P. , Fraefel W. 
Published: December 2004

AbstractThe purification of a trypsin inhibitor from Ascaris lumbricoides var. suum is described. The electrophoretically pure preparation which inhibits trypsin in a specific manner is a relatively small peptide containing 5 Asp, 4 Thr, 1 Ser, 11 Glu, 6 Pro, 6 Gly, 5 Ala, 2 Val, 10 (Cys)1/2, 3 Ile, 2 Phe, 7 Lys, 3 Arg and 1 Try.
Versuche zur Strukturermittlung der Cardenolide F, H, I, T und U aus Glossostelma carsoni (N. E. BR.) BULLOCK. Glykoside und Aglykone 298. Mitteilung
Authors: Reichstein P. , Stöcklin W. , Reichstein T. 
Published: December 2004

AbstractPhysical data and a few chemical reactions have been used to try to elucidate some of the structural features of a few cardenolides which are present in small quantities in the roots of Glossostelma carsoni (N.E. BR.) BULLOCK. The glycoside F is probably a derivative of xysmalogenin‐β‐D‐sarmentoside, whereas fermentative degradation of glycoside U yielded the genin H which was identified through paper chromatography. The genins H, I and T are possibly O‐acetyl‐cardenolides which, however, do not correspond to any known compounds.
Über den pentacylischen Chrom (III)‐Komplex aus 1,6‐Di‐(2‐amino‐benzolsulfonamido)‐hexan ⇉β‐Naphtol
Authors: Schetty G. 
Published: December 2004

AbstractA five‐ or six‐membered ring in pentacyclic azo‐dyestuff‐chromium complexes with the sandwich arrangement, having sulphonamido groups as complex formers, was extended into a nine‐membered ring. This altered not only the electron spectrum but also the stability of the complex. Whilst the five‐ and six‐membered pentacycles are very stable, the corresponding nine‐membered ring complex is considerably less stable. Its stability approaches that of the corresponding 1:2‐Cr complexes which, because of deformed valency angles, are very strained and, therefore, are also very unstable. This tension is counteracted in pentacycles having a lower number of members (5 and 6), and so the system is stabilised. If the number of ring members is increased, this counteraction is reduced and, therefore, the stabilising effect is lessened.
Photoisomerisierung von Pyrazolen und Indazolen zu Imidazolen bzw. Benzimidazolen und 2‐Amino‐benzonitrilen
Authors: Tiefenthaler H. , Dörscheln W. , Göth H. , Schmid H. 
Published: December 2004

AbstractIt is shown that pyrazoles and indazoles undergo photochemical bond‐switching.
6‐Desoxy‐L‐idose, 6‐Desoxy‐L‐sorbose und 6‐Desoxy‐L‐psicose. Desoxyzucker, 41. Mittelung [1]
Authors: Kaufmann Heinz , Reischstein T. 
Published: December 2004

AbstractAlthough crystalline 6‐deoxy‐L‐idose (2) and crystalline 6‐deoxy‐L‐sorbose (3) have similar melting points and specific rotations, they can be conclusively differentiated from one another through paper chromatography and paper electrophoresis. 6‐Deoxy‐L‐idose cannot be converted into 6‐deoxy‐L‐sorbose on short heating in very dilute aequeous mineral acids. The synthesis of amorphous 6‐deoxy‐L‐psicose (17), through oxidative fermentation of 6‐deoxy‐L‐allitol with Acetobacter suboxydans, has been described.
Steroide und Sexualhormone 233. Mitteilung [1]. Synthese von 4 stereoisomeren 1, 4‐Oxido‐3‐oxa‐A‐homo‐androstan‐Derivaten
Authors: Eggart Fr L. G. , Wehrli H. 
Published: December 2004

AbstractA synthesis of the four stereoisomeric 1,4‐oxido‐3‐oxa‐A‐homo‐androstane‐derivatives 3, 9, 13, and 19 is described, starting from the lactones 1, 11, and 15.
Photochemische Reaktionen 42. Mitteilung [1]. Photoisomerisierung von α, β‐Epoxyketonen II Der sterische Verlauf der Umlagerung von 3‐Oxo‐4, 5‐oxido‐Steroiden
Authors: Wehrli H. , Lehmann C. , Iizuka T. , Schaffner K. , Jeger O. 
Published: December 2004

AbstractThe photorearrangement previously described [3] of saturated and Δ1‐unsaturated 3‐oxo‐4,5‐epoxy‐10β‐steroids to 3,5‐dioxo‐10(5 →4)‐abeo compounds proceeds most likely via a radical 1,2‐alkyl shift (Chart 1). The similar rearrangements of the related 10α‐epoxyketone 10 and the 4‐methyl‐epoxyketones 13, 15, 16, 20 and 21 to the corresponding 3,5‐diketones occurred without epimerization at the migrating carbon atom (C‐10) and the site of substitution (C‐4) (Chart 3). The stereochemical control of the rearrangement is in agreement with the earlier proposed mechanism of a concerted alkyl radical shift in these alicyclic systems.
Synthese der Dl‐Form eines natürlichen Prostaglandins. Vorläufige Mitteilung
Authors: Hardegger E. , Schenk H. P. , Broger E. 
Published: December 2004

AbstractAusgehend vom bekannten, leicht zugänglichen Cyclopentenon‐Derivat I wird ein präparativ gangbarer Weg skizziert, der zur Racemform des natürlichen Prostaglandins E1‐278 und zu rac‐Prostaglandin E1‐237 führt.
Spektroskopische Eigenschaften alkylsubstituierter Diazulyle (Die photochemische Darstellung des 3,3′ und des 2,2′ ‐Di‐guaj‐azulyls)
Authors: Hagen R. , Heilbronner E. , Straub P. A. 
Published: December 2004

AbstractIrradiation with light of 366 nm wave‐length of guay‐azulene‐2‐sulfonic acid (IV) or of guay‐azulene‐3‐sulfonic acid (I) dissolved in concentrated sulfuric acid yields 2,2′‐di‐guayazulyl (VI) or 3,3′‐di‐guay‐azulyl (III) respectively. The nmr and electronic spectra of III and VI and of their conjugate acids are recorded. The essential features of the electronic spectra of III and VI can be understood in terms of a model based on SIMPSON'S «independent system approach».
Über primäre Disazofarbstoffe mit Aminonaphtol‐sulfonsäuren
Authors: Schneider L. 
Published: December 2004

AbstractDisazo dyes from 6‐amino‐1‐hydroxy‐naphthalene‐3‐sulfonic acid (J acid) were synthesized by coupling ortho‐hydroxy monoazo dyes with different diazonium compounds in acid medium (dyes No 3–14. A second coupling to the ortho position of the amino group was also possible with the copper complexes of o,o' ‐dihydroxy monoazo dyes from 8‐amino‐1‐hydroxynaphthalene‐3,6‐disulfonic acid (H acid) dyes No 19–22). This is a reversal of the well known rule that the formation of disazo dyes with aminonaphthol‐sulfonic acids is only practicable when an acid coupling is followed by an alkaline one. 5‐Amino‐1‐hydroxy‐naphthalene‐3‐sulfonic acid (M acid), which is said to form no disazo dyes, could be coupled twice with several diazonium compounds to yield disazo dyes (dyes No 24, 26, 27, 29).
Drevogenin A und Drevogenin B, zusätzlicher Strukturbeweis. Glykoside und Aglykone, 306. Mitteilung
Authors: Bhatnagar Ajay S. , Stöcklin W. , Reichstein T. 
Published: December 2004

AbstractDrevogenin B is shown to be 11‐O‐acetyl‐drevogenin P. The earlier derived structure for drevogenin A (11‐O‐acetyl‐drevogenin P) is further confirmed by conversion of 3‐O‐acetyl‐drevogenin A.
Cycloaddition von N‐Phenylmaleinimid an (1,2,3,6‐Tetrahydropyridyl)‐indole
Authors: Beck D. , Schenker K. 
Published: December 2004

Abstract1‐Methyl‐2‐and 1‐methyl‐3‐(1‐methyl‐1,2,3,6‐tetrahydro‐4‐pyridyl)‐indole undergo 1,4‐cycloaddition (formally of the DIELS‐ALDER‐type) with N‐phenyl‐maleimide, leading to the pentacyclic compounds III and IV.
Die Fraktionierung von Serumproteinen mit flüssigen Phasenpaaren. 3. Mitteilung [1] Eine Zentrifuge für Gegenstromverteilung
Authors: Tavel P. V. , Bolliger W. 
Published: December 2004

AbstractEine Zentrifuge zur schrittweisen Gegenstromverteilung ist gebaut worden, mit welcher die Phasentrennung nach jedem Verteilungsschritt beschleunigt werden kann. Sie eignet sich für multiplikative Verteilungen mit nahezu kritischen Phasenpaaren und andern Systemen, deren Phasen sich nur langsam trennen. Die Zentrifuge enthält 40 Verteilelemente zu 27 ml und arbeitet voll automatisch auch im Kaltraum. Sie ermöglicht 3 Arbeitsweisen: Schrittweiser Transport der spezifisch leichteren order der schwereren Phase, oder alternierender Transport beider Phasen im Gegenstrom. Ihre Trennschärfe ist geringer als die eines CRAIG'schen Apparates, da sich die überführten Phasenvolumina jeweils in die nächsten Elemente verdrängen. Versuche mit einer Komponente zeigen, dass die Verteilungen den berechneten Werten nahezu entsprechen, wenn pro Verteilungsschritt weniger als ¾ des Volumens an mobiler Phase in einem Element verschoben werden. Die Trennschärfe eines CRAIG'schen Apparates wird mit der Zentrifuge erst nach einer höheren Schrittzahl erreicht.Polyäthylenglykol von M̄w 30000 wurde in Fraktionen verschiedener Viskosität, d. h. verschiedenen mittleren Molekulargewichts, zerlegt. Ein als einheitlich angesehenes Human‐Serumalbumin zeigte eine kleine Nebenkomponente, die auch elektrophoretisch nachzuweisen war.
Synthese und Eigenschaften von 2‐(α‐Hydroxyalkyl)‐und 2‐(α‐alkoxycarbonyl)‐substituierten 4‐Methyl‐5‐(β‐hydroxyäthyl)‐thiazolen und ‐thiazoliumsalzen
Authors: Kiss J. , D'Souza R. , Spiegelberg H. 
Published: December 2004

AbstractCondensation of the tetrahydropyranyl ether of the α‐hydroxyalkyl‐thioamides with 3‐bromo‐4‐hydroxy‐2‐pentanones yields DL‐2‐(α‐hydroxyalkyl)‐4‐methyl‐5‐(β‐hydroxyethyl)‐thiazoles. By oxidation with chromic anhydride 2‐hydroxymethyl‐4‐methyl‐5‐(β‐acetoxyethyl)‐thiazole yields the corresponding 2‐formyl derivative. The latter compound reacted with GRIGNARD complexes gives the homologous DL‐2‐(α‐hydroxyalkyl)‐4‐methyl‐5‐(β‐hydroxyethyl)‐thiazoles. This is a general method for the synthesis of the thiazole part of the «active aldehydes».2‐Acetyl‐4‐methyl‐5‐(β‐hydroxyethyl)‐thiazole is also obtained by chromic oxidation of the suitable methylthiazol‐2‐yl‐carbinol.The condensation of the thioamides obtained from the α‐ethoxycarbonyl‐nitriles with 3‐bromo‐5‐acetoxy‐2‐pentanone results in the DL‐2‐(α‐ethoxycarbonyl‐alkyl)‐4‐methyl‐5‐(β‐acetoxyethyl)‐thiazoles. The α‐hydroxyl function is introduced into the 2‐(α‐ethoxycarbonyl‐alkyl) group by chlorination with sulfuryl chloride and replacement of the introduced chlorine by acetate. The latter compounds are the esters of the thiazole part of the «active α‐oxo‐carboxylic acids» (e.g. active pyruvate, etc.).The reaction of 2‐(α‐hydroxyalkyl)‐4‐methyl‐5‐(β‐hydroxyethyl)‐thiazoles and 2‐(α‐ethoxycarbonyl‐α‐acetoxy‐alkyl)‐4‐methyl‐5‐(β‐acetoxyethyl)‐thiazoles, respectively, with alkyl, alkenyl and aralkyl haloids, or with 2‐methyl‐4‐amino‐5‐bromomethyl‐pyrimidine hydrobromide results in the quaternary thiazolium compounds belonging to the group of the active aldehydes, active α‐oxo‐carboxylic acids, etc. According to this method 2‐hydroxymethyl‐thiamine bromide hydro‐bromide has been synthesized, which can be considered as the pyrophosphate‐free «active formal‐dehyde».The 2‐α‐hydrogen atom in 2‐(α‐hydroxyalkyl)‐thiazolium compounds cannot be replaced by deuterium under conditions similar to those used for the H → D exchange in thiamine.The main peaks in the mass spectra of 2‐(α‐hydroxyalkyl) substituted thiazoles and thiazolium quaternary salts are listed.
Die Elektronen‐ und Infrarotspektren von Hydraten und Clathraten des Nickelcyanids
Authors: Ludi A. , Hügi R. 
Published: December 2004

AbstractThe infrared and diffuse reflectance spectra in the visible and ultraviolet region of the following compounds have been measured: Ni(CN)2, 2 H2O, Ni(CN)2, 1½ H2O, Ni(CN)2, NH3, ¼ H2O, Ni(CN)2, NH3, R (R = C6H6, C6H5NH2, C6H5OH). The structural units of these compounds are shown to be the square planar [NiC4] and the pseudo‐octahedral [NiN4L2]‐group (L = H2O, NH3) with Ni‐C‐N‐Ni‐bridges. Additional water is present as zeolitic water. The magnetic data give a 1:1 relation of the paramagnetic pseudo‐octahedral to the diamagnetic square planar co‐ordination polyhedra.The nitrogen of the cyanide ion is close to ammonia in the spectrochemical as well as in the nephelauxetic series, the values of Dq and B being ˜1000 and ˜900 cm−1 respectively.The absorption bands of the aromatic molecules in the clathrates are shifted towards lower wave numbers compared to the corresponding solution spectra.
Über die sterische Anordnung von Chrom(III)‐ und Kobalt(III)‐1:2‐Azofarbstoff‐Komplexen mit annellierten 5/5‐ und 5/6‐Chelatringen, gebildet mit Azofarbstoffen aus 4,5‐Diphenylimidazol als Kupplungskomponente
Authors: Schetty G. 
Published: December 2004

AbstractOn cuppling 4,5‐diphenylimidazole with a diazotised o‐aminophenol or with a diazotised anthranilic acid, tridentate ligands are produced which, on co‐ordination with the metal atom, form ortho‐condensed 5/5‐ or 5/6‐membered rings. Both ligand systems can form 1:2 chromium (III) and 1:2 cobalt (III) complexes having the DREW‐PFITZNER arrangement. The dimensions of the o‐carboxyazo dyestuff fit well, those of the o‐hydroxyazo dyestuff fit badly into the octahedral crystal lattice. In the same way, on co‐ordination one dyestuff is not deformed but the other is very greatly deformed, as can be concluded from a comparison of the electron spectra of the metal‐free dyestuff with those of the complexes.
Charakterisierung einer neuen organo‐metallischen Titan‐Zink‐ Verbindung
Authors: Salzmann J.‐J. 
Published: December 2004

AbstractA new organo‐metallic titanium‐zinc compound [Ti(C5H5)2Cl]2ZnCl2 has been isolated. Its structure has been characterised by means of spectroscopic, susceptibility and dipole measurements.
Zum chemischen Verhalten des Antiphlogisticums «Azapropazon» (Mi 85) = 3‐Dimethylamino‐7‐methyl‐1,2‐(n‐propylmalonyl)‐1,2‐dihydro‐1,2,4‐benzotriazin
Authors: Mixich G. 
Published: December 2004

AbstractThe chemical properties of the new antiphlogistic substance Mi 85 (generic name ‘Azapropazone’), which contains a 1,2,4‐benzotriazine ring condensed to a 3,5‐dioxo‐pyrazolidine ring, were investigated. It is shown that this molecule is relatively easily attacked by various chemical reactants (scheme) mainly in the 3,5‐dioxo‐pyrazolidine ring and on the dimethylamino group. There are essential differences between Azapropazone and Phenylbutazone concerning their stability towards hydrolyzing and oxidizing agents.
Beiträge zur Chemie der Si‐N‐Bindung XV [1]. α,ω‐Dimethylchlorsilyl‐substituierte Cyclodisilazane
Authors: Fink Walter 
Published: December 2004

Abstractα,ω‐Dimethylchlorosily‐substituted monomeric and oligomeric cyclodisilazanes were prepared by the reaction of dimethyl‐dichlorosilane with hexamethylcyclotrisilazane in the molar ratios 1:1 to 1:3. The mechanism of these reactions was investigated.
Synthese des Thyreocalcitonins
Authors: Guttmann St. , Pless J. , Sandrin Ed. , Jaquenoud P.‐A. , Bossert H. , Willems H. 
Published: December 2004

AbstractA total synthesis of hog thyrocalcitonin is described. A protected C‐terminal tridecapeptide amid (20–32) was coupled with a protected central decapeptide (10–19), and the resulting protected tricosapeptide amide (10–32) was reacted with the N‐terminal protected nonapeptide (1–9). After elimination of the protective groups, a free dotriacontapeptide amide was obtained whose physical, chemical and biological behaviour was indistinguishable from that of the natural hormone.
Steroide und Sexualhormone. 235. Mitteilung [1] Über eine neue ergiebige Synthese von A‐nor‐Testosteron und dessen 6‐Dehydro‐Derivat sowie von 7β‐Methyl‐A‐nor‐testosteron
Authors: Pfister J. , Lehmann [2] C. , Wehrli H. 
Published: December 2004

AbstractA novel synthetic approach to 2‐oxo‐Δ3‐A‐nor‐steroids is described. The photochemical ring contraction of epoxyketones, cf. 4 → 5, serves as the key step of this procedure, which gives notably higher yields than the previously published syntheses (e.g., overall yield 6 → 10 40%).
Echange d'oxygène lors de la substitution électrophile des phénols
Authors: Dahn H. , Aubort J.‐D. 
Published: December 2004

AbstractIn the bromodesulfonation of sodium 2, 6‐dibromophenol‐4‐sulfonate (I) and similar compounds, the relatively stable quinoloid intermediate II exchanges its carbonyl oxygen with that of H218O by an addition‐elimination process. The exchange is slower than the formation of the product III; it is roughly comparable to the exchange velocity of quinones of similar structure. By reversibility of the electrophilic additon step, 18O is incorporated into the starting phenol I. In electrophilic substitutions with shorter life‐time of the quinoloid intermediate, the oxygen exchange is difficult or impossible to observe.