bluuebunny/crossref_metadata_2025 huggingface dataset:
The Nature of the Azonium Cation as Evidenced by X‐Ray Photoelectron Spectroscopy
Authors: Haselbach Edwin , Henriksson Anita , Schmelzer Andreas , Berthou Hervè
Published: December 2004

The question of the classical or non‐classical nature of aryl‐substituted azonium cations as well as of the pyridazinium cation has been settled by X‐ray photoelectron spectroscopy in favour of the classical structure. The relative magnitude of the observed N1s binding energies is reasonably well reproduced on the basis of the theoretically calculated charge structure of these ions. The relative magnitude of the crucial intramolecular potential terms, appearing in the theoretical treatment, is also suggested from PMR.‐investigations on protonated azo‐compounds. The electronic structure of these species is compared with that implied by commonly accepted classical valence structures and parallels to carbo‐cations are drawn. MINDO/2 calculations of the proton affinities of azo‐compounds, considering structurally different conjugate acids, also support a classical azonium cation structure. The gas phase basicity of azobenzene is predicted to be higher than that of azomethane.
Observation of the Neophyl Radical Rearrangement by Electron Spin Resonance Spectroscopy
Authors: Hamilton Edwin J. , Fischer Hanns
Published: December 2004

The rearrangement of the 2‐methyl‐2‐phenylpropyl (or neophyl) radical 1 to the 1‐methyl‐1‐benzylethyl radical 2 is observed by ESR. spectroscopy during photolysis of di‐t‐butylperoxide in t‐butylbenzene at 270–360 K. The energy of activation of the rearrangement is determined to be (43 ± 9) kJ mol−1.
Strukturanalyse von Scillicyanosid‐pentahydrat. 58. Mitteilung über Herzglykoside [1]
Authors: Jaunin André , Weber Hans Peter , Wartburg Albert Von
Published: December 2004

The crystal structure of the steroidal glycoside scillicyanosid‐pentahydrate has been determined by X‐ray analysis. The rings of the steroid backbone are A/B cis, B/C trans, and C/D cis fused, the six substituents are all in β‐position (5β‐D‐gluco‐pyranoside, 10β‐aldehyde, 13β‐methyl, 14β‐hydroxy, 16β‐acetoxy, and a 17β‐lactone ring). The crystal structure displays a complex system of hydrogen bonds between the five water molecules and the various oxygen functions in the steroidal glycoside. There are no intramolecular hydrogen bonds. 624 structural parameters were refined to an R‐value of 0.059 with 1907 significant structure factors.
3‐Chlor‐4,5‐dihydrofuran ‐ ein nützlicher Synthesebaustein
Authors: Schlosser Manfred , Schaub Bruno , Spahic Bojana , Sleiter Giancarlo
Published: December 2004

3‐Chloro‐4,5‐dihydrofuran can be easily substituted in the 2‐position by metalation with butyllithium followed by treatment with an electrophilic reagent. The resulting derivatives may be dehalogenated to give compounds where the original ring structure is either retained or opened. In the latter case alk‐3‐yne‐1‐ols, and 1‐hydroxy‐4‐alkanones are formed.
Arbeiten über Phosphorsäure‐ und Thiophosphorsäureester mit einem heterocyclischen Substituenten. 7. Mitteilung. Thio‐ und Dithiophosphorsäureester von der Art des GS 13005 mit einem analogen oder homologen heterocyclischen Ring
Authors: Rüfenacht Kurt
Published: December 2004

To complete results presented in this and in previous papers of this series as well as published in patents of other authors a review is given on known and new variations of the heterocyclic moiety in GS 13005 type thio‐ and dithiophosphoric acid esters (1, 2) by modification of the 1,3,4‐thiadiazol‐2(3H)‐one ring 5 and by its replacement by analogue five‐ and homologue six‐membered rings.

Among new esters of this type some containing the pyrazolinone ring 3 or a 2‐alkoxy‐4H, 6H‐1,3,4‐thiadiazin‐5‐one ring 10 (homologue of the original 5‐methoxy‐1,3,4‐thiadiazol‐2(3H)‐one ring in GS 13005) show no remarkable pesticidal activity, some others containing a pyrazolering 7 or a 3(2H)‐pyridazinonc ring 8 are moderately to highly active but toxic to inauinials in the same proportion.

Attempts to prepare seven‐membered 2‐alkoxy‐ and 2‐alkylthio‐6,7‐dihydro‐l, 3,4‐thiadiazepin‐S(4H)‐ones 11, Z‐rnethoxy‐l,3,4‐thiadiazepin‐S(4H)‐one 12 (ring vinylogue of the original 5‐methoxy‐l,3,4‐thiadIazol‐2(3H)‐one ring in GS 13005) and its 7‐methyl‐derivative have been unsuccessful due to unexpected side reactions, such as: five‐ring closure of 3‐(3‐chloropropionyl)‐thio‐ and ‐dithiocarbazic acid esters 22 to pyrazolidinone derivatives 23, pyrazolinone ring closure of a 3‐(acetoacety1)‐thiocarbazic acid O‐methyl ester derivative 26, bromine attack on sulfur in 3‐(2‐alkenoyl)‐thiocarbazic O‐methyl esters 29 instead of bromine addition at the double bond, and halogen splitting off without ring closure in 3‐(2,3‐dihalogeno‐alkanoyl) ‐thiocarbazic O‐methyl esters 30 prepared by acylation of thiocarbazic acid O‐methyl ester with dihalogeno‐alkanoyl‐chlorides.
Dediazoniations of Arene Diazonium Ions in Homogeneous Solution. Part III: Heterolytic arylations in 2,2,2‐trifluoroethanol ‐ an SN1‐or an SN2‐reaction?
Authors: Burri Peter , Zollinger Heinrich
Published: December 2004

Benzenediazonium tetrafluoroborate in 2,2,2‐trifluoroethanol decomposes to give fluorobenzene and phenyl 2,2,2‐trifluoroethyl ether. In the presence of benzene, toluene, trifluoromethyl‐benzene or anisole, the respective biphenyl derivatives are formed in addition to fluorobenzene and the ether. The distribution of the isomeric substituted biphenyls is consistent with an electrophilic substitution. No homolytic products (diazo tars, benzene) are formed. The reaction kinetics clearly show that ether formation and aryl‐dediazoniations are of second‐order type, i.e. that trifluoroethanol and the benzene derivatives mentioned above are rate‐determining factors. It is shown that these results exclude the SN1‐mechanism which is usually assumed for heterolytic dediazoniations; free aryl cations are therefore not involved in these reactions. An SN2‐like mechanism seems to be the most likely, but one involving an encounter complex containing the dissociated benzenediazonium ion is also consistent with the experimental data.
The Oxidation of the Double Bonds of β‐Elemene
Authors: Thomas Alan F. , Vial Christian , Ozainne Michel , Ohloff Günter
Published: December 2004

Peracid oxidation of β‐elemene (6) occurs by attack specifically on the isolated [isopropenyl] group at C(4). The structures of the epoxides thus obtained were demonstrated by [conversion] to tetrahydrogeijerol 12 (R  H), which was identical with the substance obtained from geijerone (2) by reduction, first catalytically, then with metal hydride. Ozonolysis of β‐elemene is less specific, attack occurring on the other isopropenyl group (at C(2)) in addition to the one at C(4), and subsequently on the vinyl group (at C(1)). The structures of the ozonolysis products were confirmed by a sequence of reactions from elemol.
Über die Konstitution und die Konfiguration der Rifamycine B, O, S und SV
Authors: Oppolzer Wolfgang , Prelog Vladimir
Published: December 2004

Degradation experiments and spectroscopic (UV., VIS., IR., and 1H‐NMR.) evidence have led to the elucidation of the complete constitution and of a part of the configuration of rifamycins B, O, S, and SV.
Dienol‐Benzol‐Umlagerung von Penta‐2,4‐dienyl‐benzocyclohexadienolen
Authors: Greuter Hans , Hansen Hans‐Jürgen , Schmid Hans
Published: December 2004

1‐Hydroxy‐2‐methyl‐2‐(penta‐2,4‐dienyl)‐1,2‐dihydronaphthalene (2), on treatment with 0,75N H2SO4 in ether at 0°, underwent a [1s, 2s]‐sigmatropic rearrangement to give 2‐methyl‐1‐(penta‐2,4‐dienyl)‐naphthalene (5), cf. scheme 2. 2‐Hydroxy‐1‐methyl‐1‐(penta‐2,4‐dienyl)‐1,2‐dihydronaphthalene (4) under the same conditions gave 38% of the [1s, 2s]‐product 1‐methyl‐2‐(penta‐2,4‐dienyl)‐naphthalene (6), together with 26% 1‐methylnaphthalene, 21% 1‐methyl‐4‐(penta‐2,4‐dienyl)‐naphthalene (7) and 1% 1‐methyl‐5‐(penta‐2,4‐dienyl)‐naphthalene (8), cf. scheme 2. Most likely the latter two naphthalene derivatives at least are products of an intermolecular process.
Specifically π→π* Induced Photoreactions of α,β‐Unsaturated Ketones: Hydrogen Abstraction by the α‐carbon. (Preliminary Communication)
Authors: Gloor Jean , Bernardinelli Gérald , Gerdil Raymond , Schaffner Kurt
Published: December 2004

Irradiations at 254 nm of the α,β‐unsaturated γ‐dimethoxy‐methyl ketone 7 in iso‐octane and t‐butyl alcohol afforded in a specifically π→π*induced process and in high chemical yield the epimeric products 9 and 10. These products were not formed on n→π* excitation of 7 at > 340 nm, but triplet energy transfer to 1,3‐cyclohexadiene could be observed. Photolyses of the hexadeuterio analog 7‐d6 at 254 nm led to the fully deuteriated products (cf. 9‐d6) in both solvents, with stereospecific incorporation of a deuterium atom in position C(1α). The structures of 9 and 10 were determined by an X‐ray diffraction analysis of 9 and chemical correlations of the two products. The structural constraints in 7 demand a hitherto unprecedented direct transfer of a methoxyl hydrogen to the α‐carbon of the excited enone and formation of intermediate 8.
Tétraméthylidène‐2, 3, 5, 6‐oxa‐7‐bicyclo[2.2.1]heptane. (Communication préliminaire)
Authors: Vogel Pierre , Florey André
Published: December 2004

Preparation of the title compound (4) is described. An important transannular effect between the two unconjugated s‐cis‐butadiene chromophores is observed by comparison of the UV. spectra of the dimethylidene‐oxanorbornane 3 and the tetramethylidene‐oxanor‐bornane 4.
Antibiotic X‐5108. VI. Relative configuration of the tetrahydrofuran moiety of goldinamine. Preliminary communication
Authors: Maehr Hubert , Williams Thomas H. , Leach Michael , Stempel Arthur
Published: December 2004

Die relative Konfiguration des 3,4‐dihydroxy‐2,5‐disubstituierten Tetrahydrofuranrings, ein Strukturelement dcs Antibiotikum X‐5108 und Mocimycin, wurde durch NMR.‐Spektroskopie unter Zuhilfenahme von Modellverbindungen bestimmt. Alle vier Substituenten liegen auf derselben Ringseite.
3‐C‐Hydroxymethyl‐D‐riburonic Acid Synthesis of the Branched‐Chain Uronic Acid and comparison with a carbohydrate component of a naturally occurring bilirubin conjugate
Authors: Blackstock Walter P. , Kuenzle Clive C. , Eugster Conrad H.
Published: December 2004

A novel carbohydrate has previously been isolated from human bile as a complex glycoside of bilirubin [1]. This compound has been tentatively identified as 3‐C‐hydroxymethyl‐D‐riburonic acid. To test this structural assignment the proposed branched‐chain uronic acid was synthesized. Gas chromatographic and mass spectrometric comparison of the natural and synthetic materials indicated that the proposed structure, 3‐C‐hydroxymethyl‐D‐riburonic acid, did not apply to thc natural product.
Steroide und Sexualhormone. 253. Mitteilung [1]. Synthetische Versuche in der Limoninreihe II Partialsynthetischer Aufbau der Ringe A und A' von Limonin
Authors: Lüthy Christoph , Schlatter Hans‐Rudolf , Graf Walter
Published: December 2004

Two different synthetic approaches towards compound 16 with the ring A/A'‐partial structure of limonin (1) are described.
Darstellung und Eigenschaften von π‐Cyclopentadienylrhodium‐bis(tert.‐phosphit)‐Komplexen
Authors: Neukomm Heinrich , Werner Helmut
Published: December 2004

The half‐sandwich type compounds C5H5Rh[P(OR)3]2 (R = CH3, C2H5, C6H5, p‐CH3C6H4, p‐ClC6H4) have been prepared from [(P(OR)3)2RhCl]2 and NaC5H5. The NMR. data as well as the IR. and mass spectra of the new compounds will be discussed. The preparation of C5H5Rh(CO)P(OC2H5)3 is also reported.
Oxydation von Allylalkoholen mit Blei(IV)‐acetat
Authors: Ehrenfreund Josef , Zink Markus Peter , Wolf Hans Richard
Published: December 2004

Lead tetraacetate (LTA) oxidation of the allylic alcohols1, 10, 14and19leads to the formation of the epoxides2, 11, 15and20, products of a novel internal addition reaction of the electron deficient alcohol oxygen to the allylic double bond. In some cases (10, 14) the formation of a new type of acetoxylated enolethers (12, 16) is observed. The LTA oxidation of the allylic dienols21and29gives rise to the formation of the epoxyacetates25and33, products of a similar internal addition reaction. Furthermore, a variety of cyclization products (22, 23, 24, 26, 30, 31, 32and34) has been isolated whose formation requires an isomerisation of the allylictransdouble bond to acisone.
Transpositions de doubles liaisons dep‐menthènes et dep‐menthadiènes catalysées par des bases
Authors: Ferro Alberto , Naves Yves‐René
Published: December 2004

The displacements of double bonds by basic catalysts (N‐lithioethylene diamine with an excess of ethylene diamine, potassiumt‐butylate in dimethylsulfoxide, benzyl‐sodium in boiling xylene) are studied onp‐menthenes andp‐menthadienes. The isomerizations ofp‐menthadienes are accompanied by dehydrogenation. A representative mechanism of isomerization and dehydrogenation according to the catalyst is proposed for limonene.
Azidiniumsalze. 9.Mitteilung [1]. Struktur‐Reaktivitäts‐Beziehungen in Serien quartärer N‐Heteroaromaten: Aciditätskonstanten von 2‐Amino‐cyclimonium‐Ionen als σHet‐Konstanten
Authors: Balli Heinz , Hellrung Bruno , Hinsken Hans
Published: December 2004

Aus den Aciditätskonstanten kernquartärer Amino‐N‐Heteroaromaten werden σHet‐Konstanten abgeleitet, die in eine lineare Freie Energie‐Beziehung einbezogen werden. Die Synthese der benötigten Amin‐Salze und die Messung ihrer Aciditätskonstanten Kμ (25°, μ = 0,01, Wasser) werden mitgeteilt.
Arbeiten über Phosphorsäure‐ und Thiophosphorsäureester mit einem heterocyclischen Substituenten. 8. Mitteilung. Das Stäubli‐Verfahren, eine Eintopf‐Kondensation von Thiophosphorverbindungen (, XO,S), Aldehyden und Heterocyclen (mit saurer NH‐Gruppe)
Authors: Rüfenacht Kurt
Published: December 2004

The condensation reaction of thiophosphoric compounds 1, aldehydes and heterocycles 3 with an acidic NH‐group in strong mineral acid of specific concentration to asymmetrical compounds 4, called Stäubli procedure, differs from the Mannich‐type reaction catalyzed by weak or dilute acid (aminoalkylation of Hellmann & Opitz) and from the Tscherniac‐Einhorn‐type condensation in concentrated sulfuric acid (amidomethylation of Hellmann). Its main feature is the acidity of the two condensation participants 1 and 3; therefore an attuned concentration of mineral acid is required to activate them each to its individual optimum extent. Their pK difference, however, is sufficient to differentiate their nucleophility and reactivity and to prevent a simultaneous reaction of both of them with the aldehyde provocating side reactions to symmetrical by‐products such as 13, 14 and 15.
8‐Oxabicyclo[5.1.0]octa‐2,4‐dien Thermische und lichtinduzierte Isomerisierung
Authors: Schiess Peter , Wisson Markus
Published: December 2004

8‐Oxabicyclo[5.1.0]octa‐2, 4‐diene (1) yields 2,4,6‐heptatrienaldehyde as major primary rearrangement product upon pyrolysis in a flow system between 200 and 300°. Above 500° o‐cresol, benzaldehyde and benzene are obtained. Bicyclo[3.2.0]hept‐2‐en‐7‐one, 2,3‐ and 2, 5‐dihydrobenzaldehyde are shown to be intermediates in this transformation to stable aromatic products. The observed conversions can be rationalized as proceeding mostly through allowed pericyclic reaction steps with heterogeneous, acid catalysed reactions participating to a minor extent. Irradiation of 1 affords 3‐oxatricyclo[4.2.0.02,4]oct‐7‐ene, 2,4,6‐heptatrienal and 3,5‐cycloheptadienone. Upon sensitized irradiation only the latter two compounds are formed.
Vinca Alkaloids XXXIII [1]. Microbiological Conversions of Vincaleukoblastine (VLB, Vinblastine), an Antitumor Alkaloid from Vinca rosea. LINN
Authors: Neuss N. , Mallett G. E. , Brannon D. R. , Mabe J. A. , Horton H. R. , Huckstep L. L.
Published: December 2004

The conversion of VLB using different Streptomycetes led to the isolation of VLB‐ether (3) and Hydroxy VLB (6). The structural assignments have been made by NMR. and high resolution mass spectral data.
13C‐NMR. Spectroscopy of Naturally Occurring Substances. XXXV. Labdanic diterpenes
Authors: Buckwalter Brian L. , Burfitt Ivor R. , Nagel Arthur A. , Wenkert Ernest , Näf Ferdinand
Published: December 2004

A total carbon shift analysis of several representatives of the labdane diterpene family of natural products is presented. The shift assignment is based on the prior shift designation of some synthetic trans‐decalin derivatives.
13C‐Kernresonanzspektroskopische Untersuchung der Komplexierung von synthetischen «Carrier»‐Molekeln mit Ca2+‐Ionen
Authors: Büchi Rolf , Pretsch Ernö
Published: December 2004

The complex formation between CaCl2 and the ion carrier ligands 1 and 2 was investigated with 13C‐NMR. spectroscopy. In methanol as solvent, the ligands form complexes with both 1:2‐ and 1:1‐stoichiometry (Ca2+/ligand). In the latter case, apart from solvent molecules, the ligand's two amide carbonyl groups and two ether oxygenatoms probably take part in the coordination of the metal cation. In contrast, when using a non polar solvent (CDCl3), 2 forms only a complex with 1:2‐stoichiometry, whereas 1 may also form a 1:1‐complex in which the ester carbonylgroups participate in the coordination too.
Low Temperature Photochemistry of the Acetone/2‐Propanol System
Authors: Henne Andreas , Fischer Hanns
Published: December 2004

During UV.‐irradiation of acetone/2‐propanol mixtures at −70° products of photo‐addition of acetone to intermediate enols are formed. The yields of these products exceed the yield of pinacol, the major room temperature product. At −70° the photoadditions are favoured by the long lifetime of acetone enol (≥ 5000 s).
Einführung der Corticoid‐Seitenkette bei Wortmannin
Authors: Haefliger Walter , Hauser Daniel
Published: December 2004

Introduction of the corticoid side chain into position 17 of wortmannin (1) and its 11‐desacetoxy derivative (2) has been achieved by masking the furan ring.
Ionisation Energies and the Electronic Structures of the N‐oxides of Azanaphthalenes and azaanthracenes
Authors: Maier John P. , Muller Jean‐François , Kubota Tanekazu , Yamakawa Masumi
Published: December 2004

The HeI photoelectron spectra of the N‐oxides of the azanaphthalenes 1–5 and of the azaanthracenes 6, 7 were ascertained. The inferred ionisation energies, and the assignments of the spectra, are presented and are discussed in respect to the electronic structures of the N‐oxides and the spectra of the azaderivatives. The data supports the description of the electronic structures of the basic heterocyclic N‐oxides based on PPP SCF calculations and the electronic abrosption spectroscopy.
Absolute Konfiguration von Azafrin
Authors: Eschenmoser Walter , Hans Eugster Conrad
Published: December 2004

By using complementary and selectively acting reagents (TiCl4 and sulfurane 16), azafrin, the main carotenoid in the rhizomes of Escobedia scabrifolia, has been shown to have the (5R:6R)‐configuration. Reaction of azafrinaldehyde (4) with (Ph3P)3RhCl leads to a mixture of 5 and 6, the latter arising probably through elimination of acetylene and recarbonylation.
Tetrakis (methylidene)cyclobutane (‘[4]Radialene’): Electronic states of the molecular ion
Authors: Bally Thomas , Buser Urs , Haselbach Edwin
Published: December 2004

The photoelectron spectrum of tetrakis (methylidene)cyclobutane (1, ‘[4]radialene’) is reported. The electronic states of 1+ are assigned on the basis of model calculations and with reference to related systems. Jahn‐Teller activity in the degenerate states is discussed. A failure of the simple LCBO‐model for the π(eg)‐orbital of 1 is noted and traced to the fact that this orbital, though having a symmetry‐equivalent π*‐counterpart, does not interact with it. This feature is confined to [4n]radialenes; their total π‐energies are therefore higher than those of the other members. It is shown that radialenes, in principle, do not constitute a class analogous to that of the linear polyenes as inferred earlier.
The Photoelectron Spectrum of Tetrafluorobutatriene
Authors: Basch Harold , Bieri Gerhard , Heilbronner Edgar , Jones Taylor B.
Published: December 2004

The He(Iα) and He(IIα) spectra of tetrafluorobutatriene 3(F) have been recorded for comparison with those of butatriene 3(H). Ab initio double‐zeta basis self‐consistent field (SCF) and configuration interaction calculations on butatriene show that, contrary to previous assignment, no shake‐up band is expected to appear in the 9–10 eV energy range of the photoelectron spectrum. Further, such SCF calculations on tetrafluorobutatriene support the use of the perfluoro effect in assigning the purely π orbital ionizations. It is argued that 3(F) is a key compound for the study of the perfluoro effect. This is supported by a qualitative comparison of its photoelectron‐spectroscopic results with those of other perfluoro systems.
Cryptates. XXV. Stability and selectivity of cation inclusion complexes of polyaza‐macrobicyclic ligands. Selective complexation of toxic heavy metal cations
Authors: Lehn Jean‐Marie , Montavon François
Published: December 2004

We have measured the stability constants of the cryptate complexes formed by ligands 1–4 with alkali, alkaline‐earth, transition metal and toxic heavy metal cations. Stabilities and selectivities of complexation of the alkali and alkaline‐earth cations are less pronounced in 1–4 than in the parent compounds 5 and 6 and decrease as the number of nitrogen sites increase. Remarkable complexation properties are found towards transition metal and toxic heavy metal cations. The intramolecular cavity of ligands 1–3 is too large for small cations like Co2+, Ni2+, Zn2+ so that the complexes formed are comparatively weak; however these cations are strongly complexed by ligand 4 whose intramolecular cavity has a much smaller size, compatible with their ionic radius. On the other hand, ligands 1–4 all form highly stable cryptates with Cd2+, Hg2+, Pb2+. Thus by the combined operation of the two structural parameters, cavity size and nature of the binding sites, cryptands 2 et 3 present very high selectivities for the complexation of these toxic heavy metal cations with respect to the biologically important ones Na+, K+, Mg2+, Ca2+, Zn2+. The selectivities of ligand 2 for Cd2+, Hg2+ and Pb2+ with respect to Zn2+ are as high as 106, 1018 and 109 respectively. They are much more pronounced than those of previously known complexing agents. Cryptands like 2 and 3 thus present a unique selectivity sequence of special interest in detoxication (decorporation, depollution). Further structural elaboration may allow to design ligands which present a given selectivity pattern of potential use in “cryptatotherapy” and “environment pollution control”. The results also provide evidence for the existence, at low pH, of protonated complexes which probably participate in an acid catalysed process for dissociation of the complexes.
8. Azidiniumsalze. 20. Mitteilung [1]. Einführung der Diazogruppe mit Azidiniumsalzen in Hydroxy‐arene und Hydroxy‐hetarene
Authors: Balli Heinz , Müller Volkmar , Sezen‐Gezgin Ayten
Published: December 2004

Diazo‐Group Transfer to Hydroxy‐arenes and Hydroxy‐hetarenes Using Azidinium Salts

Die Einführung der Diazogruppe mit 1‐Äthyl‐2‐azido‐pyridinium‐tetrafluoroborat und 2‐Azido‐3‐äthyl‐benzthiazolium‐tetrafluoroborat in Hydroxybenzole, Hydroxynaphthaline und einige Hydroxy‐hetarene wird beschrieben. Der Anwendungsbereich dieser Methode im Vergleich mit der Tosylazid‐Methode wird diskutiert.
12. Anil‐Synthese. 17. Mitteilung. Über die Herstellung von styryl‐derivaten des 2‐phenyl‐4H‐1,2,4‐triazolo [1,5‐a]pyridins
Authors: Pauchard Jean‐Paul , Siegrist Adolf Emil
Published: December 2004

Preparation of styryl derivatives of 2‐phenyl‐4H‐1,2,4‐triazolo [1,5‐a]pyridine

7‐Methyl‐2‐phenyl‐ and 2‐(3‐chloro‐4‐methylphenyl)‐4H‐1,2,4‐triazolo[1,5‐a]‐pyridines react with anils of aromatic aldehydes in the presence of dimethyl‐formamide and potassium hydroxide at 20–45° to yield the 2‐phenyl‐7‐styryl‐ and 2‐(2‐chloro‐stilben‐4‐yl)‐4H‐1,2,4‐triazolo [1,5‐a]pyridines respectively (‘Anil Synthesis’). Further, the Schiff's bases derived from o‐chloroaniline and 2‐(p‐formyl‐phenyl)‐ and 7‐formyl‐2‐phenyl‐4H‐1,2,4‐triazolo [1,5‐a]pyridine yield, with methyl‐ and with p‐tolyl‐substituted heterocycles, the corresponding heterocyclic substituted styryl and stilbenyl derivatives.
Free Radical Formation from Excited States of Aliphatic Carboxylic Acids and esters in solution as studied by electron spin resonance
Authors: Kaiser Tony , Grossi Loris , Fischer Hanns
Published: December 2004

During UV.‐irradiation of aliphatic carboxylic acids and esters in aqueous and nonaqueous solutions various alkyl and acyl type radicals derived from parent compounds and solvents have been observed by ESR.‐spectroscopy. The structures of the radicals point to α‐cleavage, β‐dehalogenation and photoreduction as major photolytic processes of carboxylic acids and esters. The relative contributions of these processes to the overall photodecompositions depend on the carboxyl substituents, on solvent and temperature. Similarities of carboxyl and carbonyl group photochemistry are discussed.
Zur strahlungslosen Desaktivierung des tiefsten angeregten Singulett‐Zustandes von 2‐Alkyl‐indazolen in neutraler und protonierter Form
Authors: Heinzelmann Willy
Published: December 2004

On the Mechanism of Radiationless Deactivation of the First Excited Singlet State of 2‐Alkyl‐indazoles

The temperature dependence of the quantum yields of fluorescence (ΦF), intersystem crossing (ΦT) and photoreactions (ΦR) have been measured for several neutral and protonated 2‐alkyl‐indazoles. The experimental data (Fig. 1 and 3) can be interpreted in terms of the reaction schemes 1 and 2 with temperature independent constants for fluorescence emission and intersystem crossing and temperature dependent photochemical primary processes. Whereas at low temperatures the sum of the quantum yields of fluorescence and intersystem crossing equals 1, at higher temperatures a very efficient radiationless deactivation process takes place (Table). Based on kinetic and photochemical data it is concluded that this deactivation proceeds via a hypersurface crossing (Fig. 2) or hypersurface touching (Fig. 4) in the course of the photochemical rearrangements 1 → 2 and 4 → 5 respectively.

Similar mechanisms are expected to be responsible for the unusual internal conversion in other heterocyclic compounds.
Die Synthese von Actinioerythrol, Violerythrin und anderen 2,2′‐Dinor‐carotinoiden
Authors: Kienzle Frank , Minder Rudolf E.
Published: December 2004

The Synthesis of Actinioerythrol, Violerythrin and other 2,2′‐Dinor‐carotenoids

2,2′‐Dinor‐carotenoids including the naturally occurring actinioerythrol (1) and the blue carotenoid violerythrin (2), as well as 2,2′‐dinor‐rhodoxanthin (25) and 2,2′‐dinor‐zeaxanthin (27) and others have been obtained by total synthesis.
Physikalisch‐chemische Eigenschaften deuterierter Verbindungen. 4. Mitteilung. Deuterierung von Kohlenwasserstoffen durch heterogen katalysierten Isotopenaustausch im Gegenstrom
Authors: Gäumann Tino , Öz Hami , Piringer Otto
Published: December 2004

The Deuteration of Hydrocarbons by Heterogeneous Catalysis in a Counter‐current Column

A counter‐current method for the perdeuteration of liquid hydrocarbons by heterogeneously catalysed isotope exchange with deuterium gas is described. The efficiency of the column which was developed for this purpose has been investigated and optimised as a function of the experimental variables. The limits of the applicability of this method are discussed.
Rh(I)‐katalysierte Umlagerungen von 3,4‐Diacycloxy‐1,5‐hexadiinen; synthese von (E)‐4‐acyloxymethyliden‐2‐cyclopenten‐1‐onen
Authors: Pürro Serge , Pryde Andrew , Zsindely Janos , Schmid Hans
Published: December 2004

Rh(I)‐Catalysed Rearrangements of 3,4‐Diacyloxy‐1,5‐hexadiynes; Synthesis of (E)‐4‐Acyloxymethyliden‐2‐cyclopenten‐1‐ones

The 3,4‐diacyloxy‐1,5‐hexadiynes3, 6and8which were synthesized according to a known, slightly modified procedure react with [Rh(CO)2Cl]2at 100° in chloroform with formation of the (E)‐4‐acyloxymethyliden‐2‐cyclopenten‐1‐ones4, 7and9(Schemes 2, 3and4), respectively.DL‐ andmeso‐3as well astrans‐ andcis‐8, give the same (E)‐isomers4and9, respectively. 3,4‐Diacetoxy‐3, 4‐dimethyl‐1, 6‐diphenyl‐1,5‐hexadiyne (10) produces with the same catalyst 2,6‐diacetoxy‐3, 4‐dimethyl‐1,6‐diphenylfulvene (11)(Scheme 5). A mechanism for the formation of the cyclopentenones is proposed inScheme 6.
Spektroskopische Untersuchungen über die Rolle des Käfig‐Effektes bei der Prädissoziation aromatischer Nitroverbindungen
Authors: Lippert Ernst , Kelm Jürgen
Published: December 2004

Photolysis of the bond Rar–NO2 contributes to quenching of the fluorescence of aromatic nitro compounds. Since no nitro compound is known which fluoresces above 20,000 cm−1 photolysis must occur via a predissociation process. Either a fluorine‐substituted nitro compound or fluorobenzene as the solvent was used for the irradiation experiments so that 19F‐NMR. spectroscopy could be used to analyse the reaction products. Cage effects play an important role. With a large distance between the radicals Rar and NO2, the phenyl radical forms a diphenyl compound with a benzenetype solvent molecule, and with small distance recombination will occur. For medium to long distances geminal recombination will also occur, not to the initial nitro compound, but to the corresponding nitrite, which in the presence of oxygen forms o‐nitrophenol. Mass spectrometry showed that the added oxygen atom is located in the nitro group.
CIDNP.‐Investigation of Photoinduced Polymerization
Authors: Borer Armand , Kirchmayr Rudolf , Rist Günther
Published: December 2004

The photochemistry and some initiator characteristics of the polymerization initiators ω,ω‐dimethoxy‐ω‐phenyl‐acetophenone (A), ω,ω‐diethoxy‐acetophenone (B) and ω,ω‐diisopropoxy‐acetophenone (C) have been studied by 1H‐ and 13C‐chemically‐induced nuclear polarization (CIDNP.) experiments. The primary reaction of initiator A is a Norrish‐type I cleavage, while for B and C Norrish‐type I and Norrish‐type II cleavages are of comparable importance. Three different recombination products could be detected for initiator A which correspond to the three canonical resonance forms of the substituted benzyl radical.

In a number of polymerization experiments the competition between reactions among initiator radicals and reactions of initiator radicals with the monomer acrylic acid methyl ester was studied at low concentrations of the monomer. These experiments give insight into the first steps of the polymerization process.

The positive sign of the α‐hydrogen hyperfine couplings of the dimethoxy‐methyl‐ and the diisoproproxymethyl‐radicals could be established, in agreement with the deviation of these radicals from planarity.

A slow square‐wave light‐modulation technique has been employed in 13C‐FT.‐experiments to measure absolute CIDNP.‐intensities.
Rubidium‐Pentafluoromanganat(III) und dessen Monohydrat, strukturelle Daten und Topotaxiebeziehungen
Authors: Günter John Ralph , Matthieu Jean‐Pierre , Oswald Hans Rudolf
Published: December 2004

Rubidiumpentafluoromanganate (III) and its monohydrate, crystal data and topotaxy

The unit cells and most probable space groups of the new compounds Rb2MnF5 · H2O and Rb2MnF5 have been determined from single crystal X‐ray diffraction data and the powder diffraction patterns indexed.

.

By analogy to the stoichiometrically similar phases high temperature K2MnF5 · H2O, the unit cell of which has also been determined and its powder diffraction pattern indexed, and (NH4)2MnF5, model structures for the rubidium salts are proposed. Both structures consist of infinite chains of corner sharing coordination octahedra [MnF6], between which the rubidium ions and in the case of the hydrate additional water molecules are located. X‐ray diffraction and scanning electron microscopical investigations of the dehydration of the hydrate clearly point to a chain controlled topotactic reaction mechnism. This supports the proposed model structures and confirms the possibility of predicting topotactic reaction mechanisms.
Macrocarpamin, ein neues Bisindolalkaloid aus Alstonia macrophylla WALL. 167. Mittelung über organische Naturstoffe
Authors: Mayerl Friedrich , Hesse Manfred
Published: December 2004

Macrocarpamine, a new bisindole alkaloid from Alstonia macrophylla WALL.

A new bisindole alkaloid give the name (−)‐macrocarpamine (3) was isolated from the bark of Alstonia macrophylla WALL. Under pyrolytic conditions 3 is cleaved into the two known bases (+)‐pleiocarpamine (2) and (−)‐anhydro macrosalhin‐methin (5) (Scheme 1). The structure of 3 (including relative configuration) was deduced on the basis of chemical evidence and from its UV.‐, IR.‐, NMR.‐ and mass spectroscopic data.
Chemical Reactions in Electrical Discharges: Preparation of perfluorinated acetylenes and nitriles. Preliminary communication
Authors: Bieri Gerhard , Stadelmann Jean‐Pierre , Thommen Fritz , Vogt Jürgen
Published: December 2004

Several fluorinated acetylenes and nitriles have been isolated from the reaction mixture obtained from Tesla excited fluorinated aromatic compounds. Differences in product distributions using Tesla or radio frequency discharges are discussed.
Inhaltsstoffe des Osmanthus‐Absolues. 1. Mitteilung: 2,5‐Epoxy‐megastigma‐6,8‐dien
Authors: Kaiser Roman , Lamparsky Dietmar
Published: December 2004

Constituents of Osmanthus Absolute, Ist communication:2,5‐Epoxy‐megastigma‐6,8‐dienes

Besides some further ionone derivatives we identified two new bicyclic oxacompounds (1a/1b) of the megastigmane type in the Osmanthus absolute. Isolation, special features of their spectral datas and synthesis starting from ethyl α‐safranate are described. The synthetic pathway choosen allowed the additional identification of four substances occurring in the same natural substrate, because some synthetic by‐products formed int he reaction sequence exhibited corresponding spectra and GLC. retention as the hitherto unknown components of the Osmanthus absolute.
Zur Photochemie von Allylaryläthern. 55. Mitteilung über Photoreaktionen
Authors: Waespe Hans‐Rudolf , Heimgartner Heinz , Schmid Hans , Hansen Hans‐Jürgen , Paul Henning , Fischer Hanns
Published: December 2004

The photochemical reactions of different allyl aryl ethers (Scheme 3) were investigated in hydrocarbons (Chap. 3.1) and in alcoholic solvents (Chap. 3.2). The composition of the photoproducts depended very much on the nature of the solvent. Irradiation (3–95 h) of different methyl substituted allyl aryl ethers (1, 3, 5, 7 and 11) with a low pressure mercury lamp (λEmiss. = 254 nm; 6 or 15 Watt) under argon (quartz vessel) resulted in the formation of 2‐, 3– and 4‐substituted phenols, dienones and products of consecutive reactions (Tables 1–4 and 6). The results suggested that all products were formed by homolytic cleavage of the CO bond in the singlet state of the ethers to intermediate radical‐geminates (Scheme 5) followed by radical recombination of the two fragments. No products were formed by concerted processes (Table 5, Schemes 5 and 6).

Upon irradiation of allyl aryl ethers lacking alkyl substituents at position 4 (1 and 5) in protic solvents, mainly 2‐ and 4‐allylated phenols were obtained (Tables 1 and 4); 3‐allylated phenols were formed only in small amounts (0.02%). However, in aromatic hydrocarbons or cyclohexane 3‐allylated phenols were obtained from 1, 5 and 11 in significant amounts (3–11%; Tables 1, 4 and 6). E.g., upon irradiation of allyl‐2,6‐dimethyl‐2,4‐cyclohexadien‐1‐one (6) besides 3‐ and 4‐allyl‐2, 6‐dimethyl‐phenol (23 and 24). Irradiation of 5 in methanol afforded 23 and 6 only in traces, whereas 24 was the main product.
On Metal‐Atom Clusters IV. Photoionization thresholds and multiphoton ionization spectra of alkali‐metal molecules
Authors: Herrmann André , Leutwyler Samuel , Schumacher Ernst , Wöste Ludger
Published: December 2004

The investigation of electronic and structural parameters of metal molecules as a function of size may be decisive for understanding and control of heterogeneous catalysis with finely divided metals. Metal‐atom clusters can be prepared by several methods, most of which yield a molecular mixture only. Expansion of an atomic vapour into vacuum through a supersonic nozzle creates a complex cluster‐spectrum which has been investigated by photoionization using a mass‐spectrometer as selective detector. Broad band single photoionization (PI.) yields the abundances and ionization thresholds for Nax(x⩽16), Kx(x⩽12) and NaxKy(x+y⩽6). Rough indications about other deactivation channels of excited alkali‐molecules are obtained from an analysis of the photoionization efficiency (PIE.) curves. Two‐photon PIE. curves with narrow‐band (laser) light sources give an accurate photoionization threshold value and detailed information on ionization processes. Two‐photon ionization spectra via a real intermediate state reached by laser excitation are equivalent to normal absorption spectra, if the exciteation step is controlled by the true transition probabilities. By investigation of the power dependence of the ion current of Na as a function of the wavelength of the tunable cw dye laser (excitation) and of the ionizing Ar+‐ or Kr+‐laser, conditions under which true spectra are obtained have been clarified, in good agreement with a photon‐kinetic model of the processes involved. Vibronic and rovibronic spectra of several transitions in Na2 and K2 have been measured. Similarly a spectrum of Na3 has been determined mass‐selectively. The scope of the new method for an absorption spectroscopy in molecular beams is discussed.
Electrical Properties of the Organic Metallic Compound bis (tetrathiotetracene)‐triiodide, (TTT)2‐I3
Authors: Hilti Bruno , Mayer Carl W.
Published: December 2004

The maximum of the d.c. conductivity of single crystals of the title compound ((TTT)2‐I3), grown by cosublimation, is shown to be at about 35K. The ratio of the b‐axis (needle axis) conductivity at the temperature of its maximum (Tm ≅ 35 K) and its value at T = 300 K (normalized conductivity σ(Tm)/σ(300)) is strongly sample dependent. Values for σ(Tm)/σ(300) as high as 8 have been obtained. From 300 K to about 120 K the conductivity σ is proportional to T−1.3. in the temperature interval 40K⩽T⩽120K we found: σ∝︁T−1. On the low temperature side of the maximum (6K⩽T⩽20K) the conductivity is proportional to Tα, with α ranging from 2 to 2,5. It is shown that impurities, misfit of the stoichiometry and/or physical sample quality (crystal perfection) drastically shift the minimum of the resistivity to higher temperatures (Fig. 5), thereby altering also the temperature dependence of the resistivity on both sides of the minimum. Our crystallographic data difference from the results published by Isett et al. and Buravov et al. (Table 1) with regard to the iodine spacings. We argue that the polarisability of the I ions in their chain direction contributes significantly to the high conductivity (σ=1000 to 1000 Ω−1 cm‐1) along the crystallographic b‐axis (needle axis).
Electronic Properties and Optical Activity of Oligopeptides. III. Some cyclohexapeptides with glycine, L‐ and D‐alanine
Authors: Iseli Max , Wagnière Georges , Brahms J. Georges , Brahms Sabine
Published: December 2004

The wavelength range of the CD. spectra of some cyclohexapeptides containing different sequences of glycine, L‐ and D‐alanine is extended down to 170 nm. This allows a relatively complete recording of the (n − π*) and (π° − π*) Cotton effects. Some striking spectral changes are observed on going from one molecule to another. The relative influence of L‐ and D‐alanyl residues is discussed: Some spectra may be qualitatively related to each other by considering the effect of an L‐residue at position q in the ring to cancel partially with the effect of a D‐residue at position q ± 3. Assuming these cyclopeptides to occur in a hydrogen‐bonded pleated sheet structure, certain dominant changes in the spectra are interpreted as reflecting a transition of the overall backbone conformation from one which is closer to the (optically inactive) symmetry Ci to another which is closer to the (optically active) symmetry C2. An attempt is made to relate the influence of L‐ and D‐substituents within hairpin bends of the pleated sheet structure to an amide sector rule.
Laserflash‐photolysis of thep‐Chloranil/naphthalene system: Characterization of the naphthalene radical cation in a fluid medium,
Authors: Gschwind Rudolf , Haselbach Edwin
Published: December 2004

Excitation ofp‐Chloranil (CA) in propylcyanide (PrCN) at room temperature leads to rapid production of3CA* which decays predominantly toCAH· withk= 1.6 · 105s−1. Observation of a photoinduced current suggests simultaneous production ofCA−formed by electron transfer quenching of3CA* by the medium. Added naphthalene (NP) quenches3CA* withkq= 7.0 · 109M−1S−1;NP+is unambigously identified as product (besidesCA−) of the electron transfer process. Dissociation of the ion pair occurs with essentially unit probability. Higher concentrations ofNPlead to the formation of (NP)+2. Pertinent spectroscopic parameters established forNP+under the conditions used are λmax= 685 nm (ϵ = 2970) using the known parameters ofCA\documentclass{article}\pagestyle{empty}\begin{document}$ 1^{+ \atop \dot{}} $\end{document}as reference.NP+andCA\documentclass{article}\pagestyle{empty}\begin{document}$ 1^{+ \atop \dot{}} $\end{document}decay by charge annihilation withkr= 4.5 · 109M−1S−1. The deviation from the diffusion controlled rate constant expected for ionic species, is discussed in view of the spin characteristics of the process. Comparison with two other ion recombination reactions leads to the conclusion that ‘inverted behaviour’ as expected fromMarcus' theory does also not show up forbackwarde−‐transfer between two ions (produced by forward e−‐transfer between two neutrals). Residual absorptions in the system are ascribed toCAH·, tentatively proposed to originate from H+‐abstraction byCA\documentclass{article}\pagestyle{empty}\begin{document}$ 1^{+ \atop \dot{}} $\end{document}from the solvent.NP+appears to be a rather stable species with respect to the medium if the latter is meticulously purified.
Simple Conversion of Colchicine into Demecolcine
Authors: Capraro Hans‐Georg , Brossi Arnold
Published: December 2004

N‐Deacetylcolchiceine (7), readily available from colchicine (1), was converted into N‐trifluoroacetyl‐deacetylcolchiceine (8). Methylation of 8 with methyl iodide in the presence of potassium carbonate afforded a mixture of N‐trifluoroacetyl‐demecolcine (10) and its isomer 11. The mixture of 10 and 11 was detrifluoroacetylated and separated by chromatography to afford demecolcine (2) and isodemecolcine (12). A more practical route to 2 started with 8, and gave N‐trifluoroacetyl‐deacetylcolchicine (13) and its isomer 14 after O‐methylation with diazomethane. N‐Methylation of 13 and 14 with methyl iodide and potassium carbonate afforded 10 and 11. The overall yield in the conversion of colchicine (1) into demecolcine (2) via 7, 8 and 13 was 55%.
New Olefinic Cyclizations by Oxymetallation. Conversion of (−)‐elemol to (−)‐selina‐4α, 11‐diol (cryptomeridiol) and (−)‐guai‐1 (10)‐ene‐4α, 11‐diol
Authors: Renold Walter , Ohloff Günther , Norin Torbjörn
Published: December 2004

Acetoxythallation of (−)‐elemol acetate (1b) yields a diacetate 2b which after treatment with lithium aluminium hydride gives (−)‐guai‐1 (10)‐ene‐4α, 11‐diol (2a). (−)‐Elemol (1a) is converted to (−)‐selina‐4α, 11‐diol (9, cryptomeridiol) by hydroxymercuration followed by reductive demercuration. (+)‐γg‐Elemene (5) similarly yields (+)‐selin‐7(11)‐en‐4α‐ol (11, juniper camphor). The stereochemistry and mechanism of these metal salt‐induced olefinic cyclization and their biogenetic implication are discussed.
Crystal Structures of the (−)‐DIOP Complexes of Nickel, Palladium and Platinum Dichloride
Authors: Gramlich Volker , Consiglio Giambattista
Published: December 2004

The crystal structures of PdCl2[(−)‐DIOP], PtCl2[(−)‐DIOP] and of NiCl2‐[(−)‐DIOP] have been determined by X‐ray analysis and refined by least‐squares methods [(−)‐DIOP=(−)‐2,2‐dimethyl‐4,5‐bis(diphenylphosphinomethyl)‐1,3‐dioxolane]. The coordination around the nickel atom is tetrahedral, the coordination around palladium and platinum is square planar. The unit cell of the palladium complex contains two non‐equivalent molecules with different conformations of the seven‐membered chelate ring involving the metal and the two phosphorus atoms. PtCl2[(−)‐DIOP] is isostructural with the corresponding palladium complex.
Charge‐Transfer‐Übergänge im Pentacyano‐benzonitril‐ferrat (II)
Authors: Calzaferri Gion , Grüniger Hans‐Rudolf
Published: December 2004

Charge Transfer Transitions of Pentacyano‐Benzonitrile‐Ferrate(II)

Pentacyano‐benzontrile‐ferrate(II) shows two charge transfer transitions, which are interpreted as central atom to benzonitrile transitions d‐1π* and d‐2π*. Selective excitation to the d‐1π* state leads to a completely reversible photoreaction. An isosbestic point is observed at 398 nm in aqueous solution.
Intramolekulare Inversionssubstitution am Dreiring von 77exo‐Brombicyclo[4.1.0]heptan‐3endo‐ol unter Bildung eines Tetrahydrofuranringes
Authors: Seebach Dieter , Neumann Helmut , Dammann Reinhard
Published: December 2004

Intramolecular Substitution under Inversion at the Threemembered Ring of 7exo‐Bromobicyclo[4.1.0]heptan‐3endo‐ol yielding a Tetrahydrofuran Ring

The reaction 1a → 2a involving substitution at a cyclopropane carbon atom can be observed only with the bromophilic alkyllithium reagents but not with the bases lithium diisopropyl amide (LDA) (Table 1) or potassium t‐butoxide (KTB). The mechanism must be an insertion as outlined in Scheme 1. ‐ The monobromides 1b, 1c and 1d are prepared stereoselectively from the acetal 3a. Again, cyclization of 1b takes only place with LDA in the presence of alkyllithium (Table 2, entries 1‐‐4) suggesting an insertion mechanism (route (a) or (b) in Scheme 2). In contrast, KTB effects the substitution in high yield with no loss (from 1c) or incorporation of deuterium at the cyclopropane substitution center (Table 2, entries 5‐‐7); the possibility is discussed that this process is an SN2‐type reaction.
Intramolecular de Mayo Reactions of 3‐Acetoxy‐2‐alkenyl‐2‐cyclohexenones. Preliminary communication
Authors: Oppolzer Wolfgang , Bird T. Geoffrey C.
Published: December 2004

The photoaddition, hydrolysis, retro‐aldol sequences 1 → 2 → 3 and 4 → 5 + 6 → 7 proceeded in high yield and in a regiospecific manner. However, the enol acetate 8 on irradiation furnished the tricyclic ketoacetate 9 as the major product, presumably by a hydrogen shift in the intermediate diradical 11. Hydrolysis of the minor photoadduct 10 gave the dione 13.
Cyclopeptid‐Antibiotika aus Aspergillus‐Arten. Struktur der Echinocandine C und D
Authors: Traber René , Keller‐Juslén Camilla , Loosli Hans‐Rudolf , Kuhn Max , Von Wartburg Albert
Published: December 2004

Cyclopeptide antibiotics from Aspergillus species. Structure of echinocandins C and D

The echinocandins B, C and D are antifungal antibiotics produced by a strain of Aspergillus rugulosus. All three metabolites are closely related representing cyclic oligopeptides composed of six amino acids and a linolic acid residue in an amide linkage. The complete structure of echinocandin B (1) has recently been established by X‐ray analysis. Structural assignments to the new minor metabolites C and D have now been made by hydrolytic and oxidative cleavage reactions, formation of N‐acyl‐α‐aminoethers as well as by chemical correlations and extensive NMR. examinations. Echinocandin C (2), C52H81N7O15, contains 3‐hydroxyhomotyrosine in the place of 3, 4‐dihydroxyhomotyrosine present in 1. Echinocandin D (3), C52H81N7O13, differs in two amino acids: 3, 4‐dihyroxyhomotyrosine and 4, 5‐dihydroxyornithine, unusual units of 1 being replaced by 3‐hydroxyhomotyrosine and ornithine.