bluuebunny/crossref_metadata_2025 huggingface dataset:
Umlagerung von Vinyl‐Cyclopropan‐Carbaminalen
Authors: Huber Martin K. , Martin Roger , Dreiding André S.
Published: December 2004

Rearrangement of Vinyl‐Cyclopropane‐Carbaminals

Both (c‐2, t‐3‐diphenyl‐r‐1‐cyclopropyl)methylene‐dipyrrolidine (4) and its (t‐2, t‐3)‐isomer 10 underwent a thermal rearrangement to (E)‐N‐2‐benzylidene‐1‐indanyl‐pyrrolidine (5). Under the conditions of the rearrangement, 5 was partially converted into 2‐benzyl‐1‐indanone (6) in a base catalysed reaction. The structures of 5 and 6 were derived from spectroscopic data and from degradation reactions.‐ N,N′‐(t‐2‐Vinyl‐r‐1‐cyclopropyl)methylene‐dipyrrolidine (11) rearranged thermally to N‐(2‐methylidene‐3‐cyclopenten‐1‐yl)pyrrolidine (12), the structure of which was established from spectroscopic evidence and from a hydrogenation to N‐(2‐methylcyclopentyl)pyrrolidine (13, cis/trans mixture 3:2).

The aminal 4 was reduced with formic acid to give N‐(c‐2, t‐3‐diphenyl‐r‐1‐cyclopropyl)methyl‐pyrrolidine (14). If perdeuterio formic acid was used, the mixture product 14‐d/14‐d2 was obtained which contained exactly one deuterium atom in its methylene group and about half a deuterium atom on C(1). This labeling pattern is mechanistically explained with the existence of a fast equilibrium between the iminium ion 19 and the enamine 18, so that 18 and 19 are considered to be plausible reactive intermediates in the above mentioned thermal rearrangement. ‐ Based on this, several mechanisms for the rearrangements 4 → 5, 10 → 5 and 11 → 12 were considered: A Pictet‐Spengler‐ or Mannich‐type reaction, which starts from the iminium ion 23 and is followed by a cyclopropylmethyl‐homoallylic rearrangement and by deprotonation (path a, Scheme 5), was judged to be improbable because the postulated intermediates could lead more easily to other stable products than the observed ones. If the reaction is formulated as a [3,3]‐sigmatropic shift occurring on exclusively the (E)‐isomer 5 suggests a concerted process whose steric course is predominantly controlled by strain factors. Alternatively, the reaction could be formulated via a dipolar (27) or a diradical (26) species derived from the enamine 22 (paths c and d, Scheme 5); attempts to trap such species by a number of agents were unsuccessful. ‐ The previously unknown aminals 10 and 11 were synthesized by standard methods.
MO‐Calculation of the Optical Activity of Oligopeptides. I. Computational Procedure and Application to Small Helices
Authors: Wagnière Georges , Iseli Max , Geiger Rudolf , Gans Werner
Published: December 2004

All‐valence electron calculations on the chiroptic properties of oligopeptides rapidly become intractable, as the size of the molecule increases. A Frozen Core procedure is here proposed, which is inspired by the PPP method. It takes explicitly into account only the (pseudo) π electrons and oxygen n electrons of the amide moieties, as well as the π electrons of eventual long‐wavelength absorbing sidegroups. Local n‐π interaction is taken into account by an adjustable parameter. Other parameters are calibrated on the isolated amide and carbonyl chromophores. The method then follows the usual SCF‐CI procedure. Rotatory strengths and f‐values for the transitions are computed without further approximations, as previously described. Comparisons with results from exciton calculations and experimental data on polypeptides show the computed quantities to have a consistent and satisfactory order of magnitude.
Proximity Effects in Acid and Base‐Catalysed Ether Formation
Authors: Grob Cyril A. , Katayama Hajime
Published: December 2004

When heated with sodium ethoxide in ethanol 7‐methylidenebicyclo[3.3.1]nonan‐3‐endo‐ol (endo‐1) is converted into 1‐methyl‐2‐oxa‐adamantane (3). This reaction involves nucleophilic addition of a hydroxy group to an unactivated olefinic bond. Formation of the cyclic ether 3 also takes place when endo‐1 is heated in aqueous ethanol. This electrophilic addition is strongly catalysed by weak acids and suppressed by weak bases. These unusual reactions proceed more slowly with 7‐methylbicyclo[3.3.1]non‐6‐en‐3‐endo‐ol (endo‐2) and can be ascribed to a proximity effect. This follows from the IR. and NMR. spectra of endo‐1 and endo‐2 which show strong intramolecular hydrogen (OH‐π) bonding. The unsaturated endo‐ and exo‐alcohols 1 and 2, respectively, undergo only exo‐complexation with silver ion.
π‐Spin distribution in the radical anion of benzo[2.2]paracyclophane and its relation to those in the radical anions of [2.2](1,4)naphthalenophanes
Authors: Bruhin Jürg , Gerson Fabian , Martin William B. , Wydler Christoph
Published: December 2004

Radical anions of benzo[2.2]paracyclophane (V) and its 1,2,12,12,14,15,17,18‐octadeuterio derivative (V‐d8) in three ethereal solvents (DME, THF and MTHF) and in the temperature range of −90 to −50° have been studied by ESR. and ENDOR. spectroscopy. The resulting hyperfine data provide a detailed picture of the π‐spin distribution in V · ⊖ which is in full accord with expectation. In particular, it is noteworthy that the naphthalene moiety accommodates almost the entire π‐spin population, as may be anticipated by the higher electron affinity of this π‐system relative to benzene. The proton coupling constants for V · ⊖ have been compared with those values for the radical anions of anti‐ and syn‐[2.2](1,4)‐naphthalenophanes (II and III, respectively) which were obtained under conditions of low frequency electron transfer between the two equivalent naphthalene moieties. Such a comparison corroborates the interpretation of the results reported previously for II · ⊖ and III · ⊖.
Dérivés du C‐méthyl‐3‐xylofurannose
Authors: Tronchet Jean M. J. , Tronchet Jeannine
Published: December 2004

3‐C‐Methylxylofuranose Derivatives

3′‐C‐methyladenosine has been known for almost ten years whereas its 3′‐epimer is still to be prepared, because of the difficulty of synthesizing the 3‐C‐methylxylo‐furanose. In this communication, the synthesis of 1,2‐O‐isoproypylidene acetal 9 and its derivatives is described. Vicinal dihydroxylation of 5‐O‐benzoyl‐3‐deoxy‐1,2‐O‐isopryopylidene‐3‐C‐methylidene‐α‐D‐erythro‐pentofuranose (6) led to the branchedchain sugar derivative 7 which was selectively tosylated to 8 whose reduction gave 9. These reactions, as well as the derivatizations of 7, 8 and 9, took place with good to excellent yields.
Bemerkungen zur Synthese von 5‐Amino‐m‐xylol‐2‐sulfonsäure und 5‐Amino‐m‐xylol‐4‐sulfonsäure
Authors: Courtin Alfred , von Tobel Hans‐Rudolf
Published: December 2004

Some comments on the syntheses of 5‐amino‐m‐xylene‐2‐sulfonic acid and 5‐amino‐m‐xylene‐4‐sulfonic acid

Treatment of 5‐amino‐m‐xylene (1) with oleum led to a 55:45 mixture of 5‐amino‐m‐xylene‐2‐sulfonic acid (2) and 5‐amino‐m‐xylene‐4‐sulfonic acid (3). The structure of both isomers was proven by reaction of sulfur dioxide with the diazonium chlorides derived from 2‐amino‐5‐nitro‐m‐xylene (5) and 4‐amino‐5‐nitro‐m‐xylene (8) giving 5‐nitro‐m‐xylene‐2‐sulfonyl chloride (6) and 5‐nitro‐m‐xylene‐4‐sulfonyl chloride (9) respectively, followed by hydrolyses to the corresponding sulfonic acids 7 and 10, and final Béchamp reductions. The sulfonic acid 2 was also prepared by sulfonation of 5‐acetylamino‐m‐xylene (4) to 5‐acetylamino‐m‐xylene‐2‐sulfonic acid (11) and subsequent hydrolysis. A further procedure for the synthesis of 3 was sulfonation of 5‐amino‐2‐chloro‐m‐xylene (12) – prepared by Béchamp reduction of 2‐chloro‐5‐nitro‐m‐xylene (13) – or of 5‐amino‐2‐bromo‐m‐xylene (15) – prepared by bromination of 4 and subsequent hydrolysis – to 5‐amino‐2‐chloro‐m‐xylene‐4‐sulfonic acid (16) and 5‐amino‐2‐bromo‐m‐xylene‐4‐sulfonic acid (17) respectively, followed by hydrogenolysis.
Kreuzkonjugierte Cyanine und Merocyanine aus Salzen des 1‐substituierten 2,3‐Dimethylchinoxalins (Vinyloge von Indigo‐imiden mit cyclisch eingebauter Imidfunktion). Vorläufige Mitteilung
Authors: Schelz Dieter
Published: December 2004

Crossed conjugated Cyanines and Merocyanines, obtained from Salts of 1‐substituted 2,3‐Dimethyl‐quinoxalines. (A second type of vinylogous Indigo‐imides.) Preliminary Communication.

On dissolving quaternary salts of 2,3‐dimethylquinoxaline in dimethylformamide or dimethylsulfoxide, a spontaneous reaction takes place: the title compounds are isolated from the reaction mixtures; they are easily oxidized, e.g. by MnO2. Mechanistic aspects are discussed.
Etude de l'action de l'oxyde d'azote (III) sur l'indène et ses homologues
Authors: Colette Maurice , Perrot Roger
Published: December 2004

Addition of nitrogen trioxide to indene and alkylindenes

N2O3 adds to indene and homologous yelding pseudonitrosites which are converted to aminoindanes. Treatment of the pseudonitrosites with alcoholic potassium hydroxide gives the correspondent nitroindenes.
Reactions with Carbo(heterylhydrazonoyl) Halides. I. Chemistry of Carbo(3‐phenylpyrazol‐5‐yl‐hydrazonoyl) Chlorides
Authors: Elmoghayar Mohamed Rifaat Hamza , Elnagdi Mohamed Hilmy , Ibrahim Mohamed Kamal Ahmed , Sallam Mohamed Mohamed Mohamed
Published: December 2004

The Carbo(3‐phenylpyrazol‐5‐yl‐hydrazonoyl) halides 1a,b react with active methylene compounds to yield the 1‐(3‐phenylpyrazol‐5‐yl)‐pyrazole derivatives 2a–k (Scheme 1). The acyclic intermediates 3a,b could be isolated from reaction of 1a,b with acetylacetone, thus establishing the substitution mechanism for these reactions.

Compounds 1a, b reacted with carbon disulfide, phenyl isothiocyanate, methyl cyanide, and with p‐chlorobenzaldehyde to yield the corresponding heterocyclic derivatives 5–8, respectively (Scheme 2).

The behaviour of compounds 2 with hydrazine hydrate is reported.
(E)‐9‐Isopropyl‐6‐methyl‐5,9‐decadien‐2‐one, a Terpenoid C14‐Ketone with a Novel Skeleton
Authors: Maurer Bruno , Ohloff Günther
Published: December 2004

(E)‐9‐Isopropyl‐6‐methyl‐5,9‐decadien‐2‐one (1a), a terpenoid C14‐ketone with a novel skeleton, was isolated from costus root oil (Saussurea lappa CLARKE) and its structure established by a two‐step synthesis from thuja ketone (2). The possible role of the new compound as an intermediate in the biosynthesis of the irones is discussed.
Valence Ionization Energies of Hydrocarbons
Authors: Bieri Gerhard , Burger Fritz , Heilbronner Edgar , Maier John P.
Published: December 2004

Experimental valence ionisation energies of 143 hydrocarbons, CnHm, have been determined from their He (IIα) (40.80 eV) and He (Iα) (21.22 eV) excited photoelectron spectra. Ionization energies, usually up to 26 eV are given in tabular form for 108 hydrocarbons with n≤6, together with their (tentative) assignment. The ionization energies up to approximately 25 eV, of 35 selected hydrocarbons with 7≤n≤10, are presented by means of their He (IIα) photoelectron spectra.
Application of the Equivalent Bond Orbital Model to the C2s‐Ionization Energies of Saturated Hydrocarbons
Authors: Bieri Gerhard , Dill James D. , Heilbronner Edgar , Schmelzer Andreas
Published: December 2004

It is shown that the ab initio STO‐3G treatment applied to simple saturated linear, branched and cyclic hydrocarbons, assuming standard geometries, yields orbital energies ϵ for their canonical orbital φj which correlate perfectly with the observed C2s ionization energies I, if Koopmans' approximation is accepted.

Applying the Foster‐Boys localization procedure to these canonical orbitals φj leads to localized orbitals λμ and their corresponding Hartree‐Fock matrix Fλ = (Fλ,μv). An examination of the matrix elements Fλ,μv, i.e. of the self‐energies Aμ = Fλ,μμ of the localized CC‐ and CH‐orbitals λμ and of the cross terms Fλ, μv (μ ≠ v) between them, leads to the conclusion that a satisfactory approximation should be obtained by setting Aμ = A for all μ, Fλ,μv = B if λμ and λv are vicinal and neglecting all other cross terms. The resulting model is nothing but the well‐known equivalent bond orbital model of Lennard‐Jones & Hall, which however can now be calibrated using the known C2s‐ionization energies of hydrocarbons. Due to the discrete structure and the wider range (∽ 8 eV) of the C2s band systems in the photoelectron spectra of these molecules this leads to a more satisfactory parametrization than using the narrower and badly resolved C2p band system.

Comparison of calculated band positions using the calibrated model with observed C2s‐band ionization energies for a series of hydrocarbons reveals that the simple equivalent bond orbital model is better than one might have expected.
Reaktionen von 3‐Dimethylamino‐2,2‐dimethyl‐2H‐azirin mit Phenolen und Halogenaromaten
Authors: Chandrasekhar B. Parthasarathi , Heimgartner Heinz , Schmid Hans
Published: December 2004

Reactions of 3‐dimethylamino‐2,2‐dimethyl‐2H‐azirine with phenols and aryl halides

The reactions of 3‐dimethylamino‐2,2‐dimethyl‐2H‐azirine (1) with phenols are described in chap. 1. The azirine 1 reacts with the 2‐formyl‐ and 2‐acetylphenols 5–8 to yield the N′‐methylidene derivatives of 2‐amino‐N,N‐dimethyl‐isobutyramide 9‐12 (Scheme 2, tautomeric form b). These products are in equilibrium with the tautomeric quinoide forms 9a‐12a. Under similar conditions 4‐hydroxybenzaldehyde did not react with 1. Reaction of 1 with 4‐hydroxycoumarine (13) gives the 4‐amino‐coumarine 14 (Scheme 2). The mechanism of these reactions is analogous to the previously reported one for the reaction of 1 with cyclic enolisable 1,3‐diketones [2] [3].

Activated phenols with pKa‐values < 8, e.g. 2‐ and 4‐nitrophenol, 2,4‐dinitrophenol and pentachlorophenol, undergo addition reactions with 1 in boiling benzene solution to give the aniline derivatives 15‐18 (Scheme 3). A reaction mechanism is given in Scheme 3: after protonation of the azirine 1 followed by attack of the phenolate ion at the amidinium‐C‐atom, the intermediate of type e undergoes a rearrangement to the spiro‐Meisenheimer complexes of type f. Ring opening leads to 15–18. A similar reaction is observed for 2,4‐dinitro‐thiophenol and 1, giving 2‐(N′‐(2,4‐dinitrophenyl)amino)‐N,N‐dimethyl‐isobutyrothioamide (19).

The azirine 1 reacts with the more acidic 2,4,6‐trinitrophenol (picric acid) to yield 3,3,6,6‐tetramethylpiperazine‐2,5‐bis(N,N‐dimethyliminium) dipicrate (21, Scheme 4). The methacrylamidinium salt 22 is the only product (97% yield) in the reaction of 8‐hydroxy‐5,7‐dinitroquinoline and 1 in acetonitrile solution. The reaction of 1 with picric acid can be explained in a similar way as the previously reported one with strong acids (cf. Scheme 1, [1] [3] [5]). An alternative mechanism without formation of the 1‐aza‐allylcation c is postulated in Scheme 5, together with a mechanism which could explain the exclusive formation of 22 in the reaction of 1 with 8‐hydroxy‐5,7‐dinitroquinoline.

In chap. 2 a few reactions of the azirine 1 with aryl halides are reported. In the reaction with 2,4‐dinitrofluorobenzene it is shown by UV. and NMR., that m,n and o are intermediates (Scheme 6). Working up the reaction mixture with water, hydrogen sulfide or benzylamine leads to the aniline derivatives 17, 19 and 26, respectively. With picryl chloride and 8‐hydroxy‐5,7‐dinitroquinoline the azirine 1 undergoes a nucleophilic aromatic substitution to afford the intermediates p and q, which via deprotonation and ring opening give acrylamidine derivatives (27 and 29, Scheme 7 and 8). The steric hindrance in p and q between the aziridine ring and the two groups in o‐position could be the reason for the different behaviour of the intermediates n and p or q (cf. Schemes 6 and 8).
A New Synthetic Route to (±)‐Perhydrohistrionicotoxin
Authors: Corey E. J. , Petrzilka Martin , Ueda Yoichiro
Published: December 2004

Starting from ethyl 2‐cyclohexen‐1‐carboxylate (3) the total synthesis of the perhydrohistrionicotoxin intermediate 23 was achieved in 25% overall‐yield. The two key steps involve a positionally specific addition of HOBr to the oxime‐olefin 7 and the alkylation of bromooxime 17 with 1‐lithio‐1‐butyne. The latter represents a novel method for stereospecific and position‐specific introduction of a nucleophilic butyl equivalent in α‐position to a ketonic carbonyl group.
Anil‐Synthese. 15. Mitteilung. Über die Herstellung von heterocyclisch substituierten Stilbenyl‐Derivaten des 2H‐1,2,3‐Triazols
Authors: Siegrist Adolf Emil , Kormány Géza , Kabas Guglielmo , Schläpfer Hans
Published: December 2004

Preparation of heterocyclic substituted stilbenyl derivatives of 2H‐1,2,3‐triazole

Schiff's bases derived from 2‐ and 4‐(p‐formylphenyl)‐2H‐1,2,3‐triazoles and o‐ or p‐chloroaniline are reacted with various p‐tolyl substitued aromatic heterocycles in the presence of dimethylformamide and potassium hydroxide or potassium t‐butoxide to yield the corresponding heterocyclic substituted stilbenes (“Anilsynthesis”). In order to avoid opening of the 2H‐1,2,3‐triazole ring, the reaction is carried out without external heating. In many cases an improvement in yield is obtained by irradiation with UV. light at the beginning of the reaction.
Konstitution und absolute Konfiguration der Rhoeadin‐Alkaloide (+)‐Alpinigenin und (+)‐cis‐Alpinigenin
Authors: Rönsch Hasso , Guggisberg Armin , Hesse Manfred , Schmid Hans
Published: December 2004

The constitution and absolute configuration of the rhoeadine alkaloids (+)‐alpinigenine and (+)‐cis‐alpinigenine.

The fundamental structure of the hemi‐acetal phenylbenzazepine alkaloid (+)‐alpinigenine (1), isolated from Papaver bracteatum LINDL., was derived essentially from 1H‐NMR.‐ and mass‐spectra of 1 and its derivatives 7, 10 and 14 (cf. Scheme 2). The positioning of the four methoxy groups in the two aromatic rings could be deduced from the 1H‐NMR.‐spectra of the N‐oxides 14 and 15 in which, as a result of favourable sterical and conformational behaviour, an interaction exists between the N‐oxide oxygen atom and one of the two ortho protons in ring C.

The B/D‐trans‐fused 1 undergoes isomerization in 1N HCl to cis‐alpinigenine (16). A stereochemical correlation between bases in the trans‐and cis‐series was enabled via an Emde degradation of the corresponding methylacetal‐methyliodides 21 resp. 19 leading to the enantiomeric isochroman derivatives 22 resp. 23 which are achiral at C (2) (Scheme 4).

The configuration at C (14) in the hemi‐acetals (eg. 1 and 16) and the methyl ethers (eg. 7 and 8) is discussed in detail (cf. Scheme 7). (+)‐Alpinigenine (1) has the (1S, 2R, 14R) configuration and (+)‐cis‐alpinigenine (16), in chloroform or acetone solution, the (1R, 2R, 14R) configuration.
Beitrag zur Massenspektrometrie substituierter α, ω‐Alkandiamine. 29. Mitteilung über massenspektrometrische Untersuchungen
Authors: Schöpp Emanuel , Hesse Manfred
Published: December 2004

Contribution to the mass spectrometry of substituted α,ω‐alkane diamines

The main mass spectral fragmentation pattern of compounds of types 1 to 4 is discussed. After loss of C6H5 · CH2 · from the molecular ion the acid correspondin to the N,N‐disubstituted residue is splitted off. The mechanism of this fragmentation reaction depends on the member of CH2‐groups between the two nitrogen atoms (Schemes 1 and 3) and on the substitution pattern of both nitrogens (Scheme 2).
Dimeric Radical Cation of 4,5,7,8‐Tetramethyl[2.2]paracyclophane
Authors: Bruhin Jürg , Gerson Fabian , Ohya‐Nishiguchi Hiroaki
Published: December 2004

Electrolytic oxidation of 4,5,7,8‐tetramethyl[2.2]paracyclophane (I) yields a paramagnetic species which by ESR. spectroscopic evidence must be ascribed to the dimeric radical cation I2 · ⊕. Analogous dimers are obtained from the 12, 13, 15, 16‐tetradeuterio‐ and 1, 1, 10, 10, 12, 13, 15, 16‐octadeuterio‐derivatives of I so that all coupling constants can be unequivocally assigned to sets of equivalent protons. The hyperfine data for I2 · ⊕ are consistent with an effective D2h or D2d symmetry, the four benzene rings lying in parallel planes.
π‐Participation in Diazoketone Hydrolysis II; Exo‐endo Cyclization Ratio in the Hydrolyses of 7‐syn‐ and 5‐endo‐Diazoacetyl‐2‐norbornene
Authors: Malherbe Roger , Dahn Hans
Published: December 2004

The rate of the acid‐catalysed hydrosis of 7‐syn‐diazoacetyl‐2‐norbornene (1a) is enhanced relative to that of the saturated analogue 5a by a factor of 835. In contrast to the behaviour of other primary diazoketones, the substitution step is no longer rate‐determining (mechanism A‐2), but so much accelerated that the preceding proton transfer becomes the slow step (mechanism A‐SE2, demonstrated by a solvent isotope effect kH/kD = 1.76). Product analysis shows 100% cyclization; the product formation is explained in terms of brexyl and brendyl type carbenium ions (or ion pairs). ‐ 5‐endo‐Diazoacetyl‐2‐norbornene (3a) shows very slight acceleration, and forms only 27% cyclization products (identical to those formed from 1a). Thus, in spite of the absence of steric hindrance by hydrogen atoms, the exo‐endo rate ratio for anchimeric assistance is ≥ 103.
Réaction d'énamines dérivées de la cyclohexanone avec le tétracyanoéthylène
Authors: Hubschwerlen Christian , Fleury Jean‐Pierre , Fritz Hans
Published: December 2004

Reaction with Tetracyanoethylene of Enamines derived from Cyclohexanone

At room temperature enamines of cyclohexanone react with tetracyanoethylene (TCNE) to give substituted tetrahydroindenes 5. The structures are assigned on the basis of 13C‐NMR. data and confirmed by hydrolysis. Spectroscopic studies (IR., UV., ESR.) at different temperatures indicate that the reaction can follow two routes: classical zwitterion formation, or a concurrent electron transfer between the enamines and TCNE leading to the derivates 5. These are the first reported examples of the γ‐carbon reactivity of an enamine.
On the Influence of Cholesterol Feeding and of a Lipogenic Diet on the Cholesterogenesis in Rat Liver in vivo
Authors: Oswald  , Wiss Verena
Published: December 2004

The existence of a main regulation site(s) of the cholesterol synthesis located after the squalene formation is demonstrated by cholesterol feeding with labelled glucose, acetate, mevalonate as precursors and by measuring the incorporation rates into cholesterol, squalene, ubiquinones, and fatty acids in rat liver in vivo.

By administration of labelled squalene in vivo it is shown that the isoprenic synthesis is inhibited between squalene and lanosterol but that other regulation site(s) after the lanosterol formation must exist.

A regulation site of the cholesterogenesis in rat liver located after the squalene synthesis is also shown after a lipogenic diet administered during 5 days. The cholesterol synthesis is thus reduced to about one third of the control rats. Another regulating site controlling the utilization of acetylcoenzyme A for the synthesis of mevalonate is also shown to exist. No indication was obtained for a regulating influence located between mevalonate and squalene.
Reaktionen von Steroiden mit Dialkylaminoschwefeltrifluoriden. I. 11β‐Hydroxysteroide. Über STeroide, 233. Mitteilung
Authors: Biollaz Michel , Kalvoda Jaroslav
Published: December 2004

Reactions of Steroids with Dialkylaminosulfur Trifluorides. I. 11β‐Hydroxysteroids.

Reactions of three types of 11β‐hydroxy steroids with dialkylaminosulfur trifluorides (DAST) have been studied. 9Δ‐unsubstituted 11‐alcohols are dehydrated with DAST to Δ9(11)‐unsaturated compounds under very mild conditions. 9α‐Chloro‐11β‐hydroxy steroids are quantitatively fluorinated in position 11 yielding the known 9α‐chloro‐11β‐fluoro derivatives. Finally, 9α, 11Δ‐fluorohydrins at 0–25° are selectively transformed with DAST into Δ11‐9α‐fluorides. When the latter reaction is run at lower temperature, the corresponding 11‐piperidinesulfinates, products of partial hydrolysis of the alkoxy‐dialkylaminosulfur difluoride intermediates postulated by Middleton, can be isolated in high yields. A rational explanation of the results is presented.
Charge‐Transfer‐Verbindungen mit Metallkomplexen. I. Bis(o‐phenylendiamido)‐Nickel‐Komplexe als Donatoren
Authors: Bäbler Fridolin , von Zelewsky Alexander
Published: December 2004

Charge Transfer Compounds of Metal Complexes. I. Bis(o‐phenylenediamido)‐Nickel Complexes as Donors

The synthesis of monosubstituted bis(o‐phenylenediamido)‐nickel complexes NiL2=Ni(C6H3(NH)2R)2 where R = H, OCH3, Cl, sec‐butyl, and of the disubstituted complex Ni(C6H2(NH)2 (CH3)2)2 is described. Substitution has a strong influence on the polarographically investigated reduction/oxidation behaviour of the complexes. Reaction of the nickel complexes with strong electron acceptors A (A = chloranil, tetracyanoethylene, 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone, 7,7,8,8‐tetracyanoquinodimethane) yields solid compounds with a stoichiometric composition NiL2: A = 1:1. IR. And UV./VIS. Spectroscopic data indicate an ionic ground state of the solids. Electrical conductivities of solids are in the range 4,3·10−3 ω−1 cm−1 to 5·10−12 ω−1 cm−1 at 298 K with activation energies of 0.33 eV to 1.68 eV.

In some cases solution equilibria in acetone or dichloromethane have also been investigated. The general scheme is:
equation image

The tight ion pair NiLA− gives no ESR.‐signal. Low temperatures or addition of R4NClO4 salts favour the formation of the ionic species.
Beitrag zur asymmetrischen Synthese bicyclischer Verbindungen unter Katalyse mit optisch aktiven Aminosäuren. Synthese von (S)‐2‐Pyrrolidin‐propionsäure und (R)‐4‐Amino‐5‐phenylvaleriansäure
Authors: Buchschacher Paul , Cassal Jean‐Marie , Fürst Andor , Meier Werner
Published: December 2004

Contribution to the asymmetric synthesis of bicyclic compounds catalysed by optically active amino acids. Synthesis of (S)‐2‐pyrrolidinepropionic acid and (R)‐4‐amino‐5‐phenylvaleric acid

The evaluation of literature data concerning the asymmetric cyclization of the prochiral monocyclic triketones 1 to the enediones 3 shows that catalysis with optically active α‐amino acids of the (S)‐series leads to an excess of products having the same absolute configuration as natural steroids at C (13), while those of the (R)‐series favour the formation of the enantiomers (Scheme 1). With 1a as substrate an inverse asymmetric course was observed using the optically active β‐amino acids 5, 8 and 10 as catalysts (Table 1). Furthermore, the synthesis of the optically active γ‐amino acids 6 and 11 using the Arndt‐Eistert process is described. The influence of these latter compounds on the asymmetric transformation of 1a into 3a has been investigated.
Identifizierung von Farnesol als Zwischenstufe in der Biosynthese des Cantharidins aus Mevalonsäurelacton. 7.Mitteilung zur Biosynthese des Cantharidins
Authors: Peter Martin G. , Woggan Wolf‐Dietrich , Schmid Hans
Published: December 2004

Identification of farnesol as an intermediate in the biosynthesis of cantharidin from mevalonolactone

Simultaneous injection of 2‐[14C]‐mevalonolactone (2‐[14C]‐1) and (E,E)‐11′,12‐[3H]‐farnesol (11′,12‐[3H]‐2) into Lytta vesicatoria L. (Coleoptera, Meloidae) yields doubly labelled cantharidin (3). The remainder of the precursor farnesol, re‐isolated from the insects after the incubation period, has incorporated 14C‐radioactivity. The labelling pattern in this farnesol, as determined by two independent degradative reaction sequences, is in agreement with the isoprene rule. Since specific incorporation of farnesol (2) into cantharidin (3), and of mevalonolactone (1) into both, farnesol (2) and cantharidin (3) is observed, the sesquiterpene alcohol 2 acts as an intermediate in the biosynthesis of the C10‐compound 3 (Scheme 1).
Carotinoide aus marinen Schwämmen (Porifera): Isolierung und Struktur von sieben Hauptcarotinoiden ausAgelas schmidtii
Authors: Buchecker Richard , Eugster Conrad Hans , Litchfield Carter
Published: December 2004

Carotenoids from Marine Sponges(Porifera): Isolation and Structure of the Seven Main Carotenoids fromAgelas schmidtii

The following carotenoids were identified in the marine spongeAgelas schmidtii: α‐carotene ((6′R)‐β, ε‐carotene (1)), isorenieratene (φ,φ‐carotene (2)), trikentriorhodin (3,8‐dihydroxy‐κ,χ‐caroten‐6‐one (3)) and zeaxanthin ((3R, 3′R)‐β, β‐carotene‐3, 3′‐diol (4)). In addition, three previously unknown carotenoids called agelaxanthin A, B and C were isolated. Spectroscopical and chemical structure elucidation showed agelaxanthin A to be (3R)‐β, φ‐caroten‐3‐ol (6) and agelaxanthin C to be a methoxy‐19,3′,8′‐trihydroxy‐7,8‐didehydro‐β, κ‐caroten‐6′‐one (7) with the methoxy group at C (2), C (3) or C (4). The limited data on age‐laxanthin B were compatible with the structure of a 19‐O‐methyl derivative of agelaxanthin C.
A Highly Stereoselective Synthesis of C(11)‐Functionalized Aromatic Steroids by an Intramolecular Benzocyclobutene‐Olefin ‐Cycloaddition. Preliminary Communication
Authors: Oppolzer Wolfgang , Petrzilka Martin , Bättig Kurt
Published: December 2004

The racemiccis‐anti‐trans‐steroids9to11have been synthesized in a highly stereoselective manner starting from 4‐methoxybenzocyclobutene carboxylic acidviathe key step8→9. (cf. Scheme 2).
Photochemische Reaktionen 94. Mitteilung. Vinyloge β‐Spaltung bei Epoxy‐enonen der Jonon‐Reihe
Authors: Frei Bruno , Eichenberger Herbert , Von Wartburg Beat , Wolf Hans Richard , Jeger Oskar
Published: December 2004

Photoinduced Vinylogous β‐Cleavage of Epoxy‐enones of the Ionone Series

The photochemistry of the α,β‐unsaturated γ,δ‐epoxy‐enones 1–3 is determined by: (i) C(γ)‐O‐scission of the epoxide (vinylogous β‐cleavage of Type A); (ii) C(γ)‐C(δ)‐cleavage of the oxirane (vinylogous β‐cleavage of Type B); (iii) (E/Z)‐isomerization of the enone chromophore. In contrast, 4 with tertiary C(β) shows no Type B cleavage.

Type A cleavage is induced both by n,π*‐ and π,π*‐excitation and arises probably from the T1‐state, but Type B cleavage is observed only on π,π*‐excitation and represents presumably a S2‐reaction.

On Type A cleavage 1–4 undergo 1,2‐alkyl‐shifts to 1,5‐dicarbonyl compounds (15–18, 25–28, 34 and 35) or rearrange to dihydrofuranes (7 and 30). The isomerization 1→7 proceeds by a stereoselective [1,3]‐sigmatropic shift.

On Type B cleavage 1–3 isomerize to a bicyclic enol‐ether (8, 29) or to a monocyclic enol‐ether (9; product of a homosigmatropic [1,5]‐shift) or undergo fragmentation to isomers such as allenes 10, 22 and 31 or cyclopropenes 11 and 21.

The non‐isolated, unstable (Z)‐epoxy‐enones 14, 19, 24 and 38 isomerize by fragmentation to the furanes 12, 23, 33 and 39 respectively, on contact with traces of acid or by heating. However, for 19 and 4, Type B cleavage may lead to the furanes 23 and 39.

On UV. irradiation of the epoxy‐enone 4 the initially formed (E/Z)‐isomers 34 and 35 yield on π,π*‐excitation the enones 37 and 40 by a vinylogous β‐fragmentation. In addition, on n,π*‐excitation 34 isomerizes to 35, which decarbonylates exclusively to the enone 37.

The reactions of 1–4 with BF3 · O(C2H5)2 were also studied (see appendix). The epoxy‐enones 1 and 2 isomerize by an 1,2‐alkyl shift in good yield to the 1,4‐dicarbonyl compounds 79 and 81, whereas 3 gives the 1,4‐diketone 83, and in small amounts the 1,5‐diketone 84. On the other hand, 4 is converted to the fluorohydroxy‐enone 85 and to the 1,5‐dicarbonyl product 34, the only isomer in this series which is identical with one of the photoproducts.
An Alternative to Automatic Titration
Authors: Schumacher Ernst , Ryser Peter , Thormann Wolfgang
Published: December 2004

Automatic titrators are designed to do exactly what a lab‐technician used to do. Much more sophisticated automation of volumetry is possible. Omegaphoresis [3] in buffer‐free [2] sample solutions automatically creates a stationary multiple component titration curve or zoned pattern with normalized concentrations of each separated species. An automatic measurement of each zone length yields their quantity. Simultaneous automatic detection of all the zones in a 10–20 component solution in less than 2 minutes, with a precision of ±2%, a required amount of the order of less than one nanomol and a resolution of ±pK < 0.01 replaces acid‐base, complexometric, and certain types of redox‐titrimetry. An option of the method allows identification of the components as well.
Crystal Structure of cis‐(4′‐Methyl‐N,N,O)‐azoxybenzene
Authors: Hoesch Lienhard , Weber Hans Peter
Published: December 2004

Kristallstruktur von cis‐(4′‐Methyl‐N,N,O)‐azoxybenzol

Durch Röntgen‐Strukturanalyse der Titelverbindung 3d konnte die Stellung des Sauerstoffatoms eindeutig festgelegt werden. Dies impliziert zugleich eine sichere Strukturzuordnung für die stellungsisomere cis‐Azoxyverbindung 4d. Frühere Strukturzuordnungen [8] für 3d und 4d werden damit zwar bestätigt, doch zeigt ein Vergleich der 1H‐NMR.‐Spektren aller vier isomeren 4‐Methyl‐azoxybenzole 1d bis 4d in Deuteriotrichlormethan, dass die früheren Zuordnungsargumente aufgrund der relativen Lage der Methylsignale in den 1H‐NMR.‐Spektren in Benzol unzureichend waren. Auch Verwendung von Tris (1,1,1,2,2,3,3‐heptafluoro‐7,7‐dimethyl‐4,6‐octandionato)europium (Eu(fod)3) als Verschiebungsreagens für die 1H‐NMR.‐Spektren von Gemischen von 3d und 4d erlaubt, im Unterschied zu der Situation bei Gemischen der stellungsisomeren trans‐4‐Methyl‐azoxybenzole 1d und 2d [18], keine eindeutige Zuordnung der Signale beider cis‐Stellungsisomeren. Dagegen lässt sich das 1H‐NMR.‐Spektrum von reinem 3d in Deuteriotrichlormethan nach Zusatz von Eu (fod)3 im Einklang mit dem Ergebnis der Röntgen‐Strukturanalyse interpretieren.

Die Röntgen‐Strukturanalyse von 3d ist die erste einer unsymmetrisch substituierten und zugleich die erste einer cis‐konfigurierten aromatischen Azoxyverbindung. Das Resultat der Analyse ist in den Fig. 1, 2 und 3 dargestellt. Bindungslängen und Winkel der Azoxygruppierung und entsprechende Werte anderer aromatisch substituierter Azo‐ und Azoxystrukturen, für die Röntgen‐Strukturanalysen bekannt sind, finden sich in Tabelle 2 zu Vergleichszwecken.
Hydroxide‐Promoted Elimination Reactions: Alkyl Halides as Substrates
Authors: Schlosser Manfred , Tarchini Claudio
Published: December 2004

Potassium hydroxide, in presence of tetraethyleneglycol dimethyl ether, easily abstracts hydrogen chloride or hydrogen bromide from secondary and tertiary halides, but primary chlorides lead to roughly equal amounts of elimination and substitution products. Addition of small quantities of trimethylamine, however, starts a catalytic cycle involving ammonium salts and favoring alkene formation. The described method appears to be more efficient and more economic than any other non‐pyrolytic process.
The Electronic Structure of Cubane (C8H8) as Revealed by Photoelectron Spectroscopy
Authors: Bischof Peter , Eaton Philip E. , Gleiter Rolf , Heilbronner Edgar , Jones Taylor B. , Musso Hans , Schmelzer Andreas , Stober Reinhard
Published: December 2004

High resolution He (Iα) and He (IIα) photoelectron spectra of cubane are reported. The assignments of the bands to different states of the cubane radical cation are made on the basis of ab initio STO‐3G and MINDO/3 calculations, using geometries optimized within each treatment. The vibrational fine‐structure observed supports the proposed assignment. An open shell MINDO/3 model for ground state cubane radical cation suggests that the Jahn‐Teller distorted system fluctuates between twelve equivalent structures of C2v‐symmetry. Localized molecular orbitals derived from the STO‐3G model of cubane indicate that the major feature which discriminates this molecule with respect to other hydrocarbons is the large interaction matrix element between the opposed CC‐σ‐orbitals of each face.
Optical Activity of Oriented Molecules IV. The anisotropic CD. and UV. Spectra of testosterone propionate
Authors: Kuball Hans‐Georg , Altschuh Joachim , Kulbach Rembert , Schönhofer Alfred
Published: December 2004

Starting from the circular dichroism (CD.) of testosterone propionate oriented in a liquid crystal matrix it is shown that the CD., measured with light beams having different directions of propagation with respect to the molecular framework, is different in magnitude and frequency dependence. The vibrational structure is analysed.

From the concentration and temperature dependence of the CD. and UV. spectra an order parameter ρ and its concentration and temperature dependence is derived. By this an estimation for the direction of the transition moment of the n → π* transition is given.
Total Synthesis of Indole and Dihydroindole Alkaloids. XIII. Further Chemistry of Catharanthine
Authors: Kutney James P. , Honda Toshio , Joshua Alummoottil V. , Lewis Norman G. , Worth Brian R.
Published: December 2004

Further investigations on the chemistry of catharanthine have provided information, valuable in the estimation of reactivity and steric requirements of the skeleton. Specific hydroxylations at C(3), C(4) and C(18) have allowed the preparation of several derivatives including (3R, 4 R)‐3‐hydroxy‐3, 4‐dihydrocatharanthine (7); (3R,4 R)‐3, 4‐dihydroxycatharanthinic acid lactone (15); 18‐decarbomethoxy‐18‐hydroxycatharanthine (40).
Der Einfluss der O‐Acetylierung auf das konformative Verhalten des Kollagen‐Modellpeptides (L‐Pro‐L‐Hyp‐Gly)10 und von Gelatine
Authors: Weber Rolf W. , Nitschmann Hans
Published: December 2004

The Influence of O‐Acetylation upon the Conformational Behaviour of the Collagen Model Peptide (L‐pro‐L‐Hyp‐Gly)10 and of Gelatin

(L‐Pro‐L‐Hyp‐Gly)10 which can be considered as a model peptide for collagen structure studies has been synthesized by the Merrifield technique. Subsequently, the hydroxyprolin residues have been acetylated by acetic acid anhydride in trifluoroacetic acid. In the same way, the hydroxyl groups of commercial bovine gelatin have been selectively acetylated. The influence of blocking the hydroxyl groups upon the thermal stability of the tripel helix formed by (L‐Pro‐L‐Hyp‐Gly)10 and upon the transition temperature and the gel stability of the gelatin has been investigated by the measurement of optical rotation, circular dichroism, molecular weights and gel melting points. The results show that O‐acetylation reduces the thermal stability of the collagen‐like tripel helices formed in solution by the synthetic peptide and during the gelation process of gelatin. Our experiments support data previously published by various authors indicating that the hydroxyl group of hydroxyprolin plays an important role in stabilizing the collagen tripel helix. The possibility to use O‐acetylated gelatin with its reduced gel forming capability for the preparation of plasma substitute solutions is discussed.
Etude thermodynamique des complexes de transfert de charge du type n‐σ* en solution Complexes de la quinoléine et de quinoléines substituées avec I2, ICI et IBr
Authors: Biselx Charles , Schaer Jean‐Jacques , Janjic Désimir
Published: December 2004

Thermodynamic study of charge transfert complexes (n‐σ*) in solution

Charge transfer complexes of quinoline and substituted quinolines (donors) with iodine, iodine chloride, and iodine bromide (acceptors) have been studied spectrophotometrically in CCl4. The 1:1 stoechiometry of these complexes was verified by means of the continous variations method and the appearance of isosbestic points. Simultaneous determination of the equilibrium constant and enthalpy of adduct formation was carried out by calorimetry.

It was observed for every donor that the equilibrium constants of the complexes studied increase with the strength of the acceptors. A linear correlation between enthalpy of adduct formation and donor strength was obtained only for the complexes Donor ICI.
Synthese von 4‐[3β, 14‐Dihydroxy‐5β, 14β‐androstan‐17β‐yl]‐3‐pyrrolin‐2‐on (Hothesimogenin). Partialsynthetische Versuche in der Reihe der Herzgifte, 11. Mitteilung
Authors: Güntert Theodor W. , Linde Horst H. A. , Ragab Mohamed S. , Spengel Sigrid
Published: December 2004

Synthesis of 4‐[3β, 14‐Dihydroxy‐5β, 14β‐androstan‐17β‐yl]‐3‐pyrrolin‐2‐one (hothesimogenin)

We describe the synthesis of 4‐[3β, 14‐Dihydroxy‐5β, 14β‐androstan‐17β‐yl]‐3‐pyrrolin‐2‐one (24‐aza‐24‐desoxa‐digitoxigenin) (7), starting from 3‐O‐acetyl‐digitoxigenin (1).
Isolation and total synthesis of (E)‐6, 10‐dimethyl‐9‐methylidene‐undec‐5‐en‐2‐one, a constituent of Costus root oil
Authors: Dubs Paul , Schenk Hans‐Peter
Published: December 2004

(E)‐6, 10‐Dimethyl‐9‐methylidene‐undec‐5‐en‐2‐one (1) has been isolated from Costus root oil. A total synthesis of this compound is reported.
Synthesis of Three Jasmin Constituents via a Central Intermediate
Authors: Dubs Paul , Stüssi Rita
Published: December 2004

Syntheses of jasmone (1), methyl jasmonate (3) and γ‐jasmolactone (2) are reported, (Z)‐nona‐1, 6‐dien‐3‐one (4) serving as common intermediate.
Azokupplungen an 3,4‐Dimethoxyfuran
Authors: Iten Peter Xaver , Eugster Conrad Hans
Published: December 2004

Diazo coupling of 3,4‐dimethoxyfuran with aryl diazonium ions

3,4‐Dimethoxyfuran (1) easily reacts with aryl diazonium chloride in aqueous pyridine in an expected 1, 4‐addition reaction. From the isolable primary addition product pyridine is displaced by alcohols, phenols or thiols to yield 4‐alkoxy‐ or 4‐phenoxy‐ or 4‐thiophenoxy‐derivatives of 2,3‐dimethoxy‐2‐buten‐4‐olide (3). Attempts to convert them into azo compounds by a base catalysed 1, 6‐elimination reaction failed. Oxidation of 3a and 3c with DDQ results in the formation of the mono p‐nitrophenylhydrazone of 3, 4‐dimethoxymaleic acid anhydride. On the other hand, the thiophenoxy compound 3g is smoothly converted by MnO2 into the authentic furan‐2‐azobenzene derivative 5.
Über die Diskrepanz zwischen klassischer und quantentheoretischer Behandlung photophysikalischer Prozesse
Authors: Lendi Karl
Published: December 2004

Eine Vielzahl photophysikalischer Prozesse kann theoretisch durch ein Dreiniveaux‐Modell beschrieben werden. Die hier kritisch diskutierten exakten Lösungen der klassischen wie auch der quantenmechanischen Behandlung können im allgemeinen weit voneinander abweichen. Es ist gezeigt, weshalb einerseits die klassische Kinetik bei den bekannten Systemen bisher erfolgreich war und welche Eigenschaften andererseits nötig wären, um die Diskrepanzen merklich in Erscheinung treten zu lassen. Insbesondere lässt eine kurze Analyse der Zeitabhängigkeit neue interessante Effekte in der Pico‐und Subpicosekundengegend erwarten.
The Condensation of Cyclic Aminoketones, Cyclohexanone and Cyclohexane‐1,4‐dione with some Phenolic Ethers in Polyphosphoric Acid
Authors: Berney Daniel
Published: December 2004

The title condensations gave respectively: gem‐bisarylated cyclic amines 3a–k or monoarylated unsaturated cyclic amines 4a–g, 1,3‐bisarylated cyclohexadienes 6a, 6b, the condensed bicyclo [2,2,2]‐octane 8. In addition the aromatic ketone 9 gave the fluorenone 10 on treatment with polyphosphoric acid (PPA).
Nickel‐katalysierte Synthese von α‐Nornicotin‐Derivaten. Vorläufige Mitteilung
Authors: Peter Heinz , Reinehr Dieter
Published: December 2004

Nickel‐catalysed Synthesis of α‐Nornicotines

Schiff's bases 1 and butadiene generally co‐oligomerize on nickel catalysts to yield octatrienyl‐substituted amines 2 and octadienyl‐substituted imines 3.

Schiff's bases 4 and 5, on the other hand, react with 1, 3‐dienes to give new [3+2]‐cycloadducts 6. In addition to the appropriately functionalized α‐nornicotine derivatives some higher oligomers are formed.
Nickel‐katalysierte Isomerisierung von Butadien‐Hydrazon‐Misch‐Oligomeren. Vorläufige Mitteilung
Authors: Blaser Hans‐Ulrich , Reinehr Dieter
Published: December 2004

Nickel‐catalysed Isomerization of Unsaturated Azocompounds

Unsaturated azocompounds, produced by the nickel‐catalysed reaction of butadiene with hydrazones, can be isomerized in presence of the same nickel catalyst. The influence of nickel concentration, temperature and structure of the azocompound on this rearrangement is described.
Nickel‐katalysierte Mischoligomerisation von 2‐Aza‐1,3‐butadienen mit 1,3‐Butadien. Vorläufige Mitteilung
Authors: Reinehr Dieter
Published: December 2004

Nickel‐catalysed Reaction of 2‐Aza‐1, 3‐butadienes with 1, 3‐Butadiene

The nickel‐catalysed reaction of butadiene with 2‐azabutadienes yields a mixture of 1 aza‐1,5,9‐cyclododecatrienes, N‐alkylidene‐divinylcyclohexylamines and open chained 2:1 adducts.
Die absolute Konfiguration der 3,5‐Diaminohexansäure aus der β‐Lysin‐Mutase‐Reaktion
Authors: Kunz Fritz , Rétey János , Arigoni Duilio , Tsai Lin , Stadtman Thressa C.
Published: December 2004

Absolute configuration of the 3,5‐diaminohexanoic acid produced in the β‐lysine mutase reaction

The (3S, 5S)‐configuration of the 3,5‐diaminohexanoic acid 3 produced by the coenzyme‐B12‐dependent β‐lysine mutase from Clostridium sticklandii has been determined by two different methods: by comparison of the 1H‐NMR.‐spectrum of its δ‐lactam with that of synthetic (±)‐cis‐and (±)‐trans‐4‐amino‐6‐methyl‐piperidones (1 and 2) and by chemical correlation with (+)‐(6S)‐6‐methyl‐piperidone‐2 (9).
Studies on Heterocyclic Colouring Matters Part III: 7a,14a‐diaza‐7,7a,14,14a‐tetrahydroquino[2,3‐b]acridine‐7,14‐diones (5,7a,12,14a‐tetraaza‐7,7a,14,14a‐tetrahydropentacene‐7,14‐diones)
Authors: Altiparmakian Rodolf
Published: December 2004

2‐Aminopyridines react with diethyl 2,5‐dioxo‐cyclohexane‐1,4‐dicarboxylate (diethyl succinylsuccinate) to give 7a,14a‐diaza‐6,7,7a,13,14,14a‐hexahydroquino‐[2,3‐b] acridine‐7,14‐diones (5,7a,1,14a‐tetraaza‐6,7,7a,13,14,14a‐hexahydropentacene‐7,14‐diones), which are aromatized to the title compounds. Oxidation of these with a mixture of sulfuric and nitric acids results in the formation of their respective 6,13‐quinones, also obtained directly from 2‐aminopyridines and diethyl 2,5‐dichloro‐1,4‐benzoquinone‐3,6‐dicarboxylate. The chromophore of the title compounds is compared with that of quinacridones.
Über die Herstellung von substituierten 2,3,4,5‐Tetrahydro‐1,2,4‐triazin‐6‐carbonitrilen und einige ihrer Abwandlungsreaktionen
Authors: Winternitz Paul
Published: December 2004

Preparation of substituted 2,3,4,5‐Tetrahydro‐1,2,4‐triazine‐6‐carbonitriles and some of its Derivatives.

The synthesis of 4‐substituted 2‐aryl‐2,3,4,5‐tetrahydro‐5‐imino‐3‐oxo‐1,2,4‐triazine‐6‐carbonitriles (3), 2‐aryl‐2,3,4,5‐tetrahydro‐3, 5‐dioxo‐1,2,4‐triazine‐6‐carbonitriles (4) and some 3‐thioxo‐derivatives thereof by a novel approach is described. In addition some possibilities for the derivatisation of these compounds are given.
Synthesis and Biological Activity of Four Adrenocorticotropin‐(1‐24)‐tetracosapeptide Analogues with N‐Terminal Deletions of Four to Seven Amino‐Acid Residues
Authors: Fauchère Jean‐Luc , Petermann Claudia
Published: December 2004

The syntheses of adrenocorticotropin‐(5–24)‐eicosapeptide, ‐(6–24)‐nonadecapeptide, ‐(7–24)‐octadecapeptide, and ‐(8–24)‐heptadecapeptide are described. Their biological activities on isolated adrenal cortex cells and adipocytes, on superfused adrenal tissue, as well as on the adenylate cyclase system of isolated cell membranes are summarized.
7‐Oxo‐deacetamidocolchiceine and 7‐Benzylimino‐deacetamido‐colchiceine: Two novel products from the base catalysed reaction of (−)‐N‐Benzylidene‐deacetylcolchiceine
Authors: Iorio Maria A. , Brossi Arnold , Silverton J. V.
Published: December 2004

Es wird gezeigt, dass bei der Racemisierung der aus natürlichem Colchicin leicht zugänglichen Schiff‐Base 1, mit Kaliumhydroxyd in Methanol, neben Benzaldehyd, Benzylamin und (−)‐N‐Desacetylcolchicinsäure (4), auch die beiden tricyclischen Verbindungen 2 order 5 erhalten werden. Die Überführung des Ketimins 2 in das Diketon 5 gelingt leicht durch saure Hydrolyse. Letzteres kann mit Benzylamin unter den gewählten Racemisierungsbedingungen direkt in (−)‐N‐Desacetyl‐colchicinsäure (4) übergeführt werden. Ein Vergleich der NMR.‐Spektren von 5 und seiner beiden Methyläther 6 und 7, mit Substanzen der Colchicin‐Reihe, gestattet die Identifizierung von 6 als 7‐Oxo‐desacetamidoisocolchicin und von 7 als 7‐Oxo‐desacetamidocolchicin, erlaubt jedoch keine eindeutige Zuordnung der beiden Sauerstoffunktionen im Ring C des Diketons 5. Eine solche konnte jedoch durch eine Röntgenanalyse weiter präzisiert werden. Diese ergibt nämlich, dass das Diketon 5 ein durch Wasserstoffbrücken stabilisiertes Dimeres der Tautomeren 5a (Ring C wie Isocolchicein) und 5b (Ring C wie Colchicein) darstellt.