摘要:

AbstractTrimethylsilyl‐enolethers of 5α‐ and 5β‐cholestan‐3‐on were investigated by gas chromatography and mass spectrometry. These derivatives are readily prepared and well suited for gas chromatographic analysis. In the mass spectrum they show fairly intense fragmentation, which appears to be characteristic for some structural elements in the surroundings of the functional group (excluding stereochemistry). This fragmentation may be useful for the structure elucidation of 3‐oxo‐steroids and related compounds.For comparison purposes the corresponding enolacetates were al

ISSN:0018-019X    

DOI:10.1002/hlca.19690520102

出版商:WILEY‐VCH Verlag GmbH    

年代:1969

数据来源: WILEY

摘要:

AbstractBy feeding the antLasius fuliginosusLATR. with [14C]‐1‐acetate, [14C]‐2‐acetate, [14C]‐2‐mevalonate, [14C]‐2‐mevalonate, [14C]‐1‐glucose and [14C]‐U‐glucose, incorporation ratios of 10−4– 0,15% were obtained in the sesquiterpenoid dendrolasin. It was shown by analysis of the labelling pattern in dendrolasin that the insertions were spread over the whole molecule in exactly the manner that would be expecte

ISSN:0018-019X    

DOI:10.1002/hlca.19690520103

出版商:WILEY‐VCH Verlag GmbH    

年代:1969

数据来源: WILEY

摘要:

AbstractThe absolute oil of cassie (Acacia farnesianaWILLD.) has been thoroughly investigated by using several combined chromatographic techniques. Among the 38 new constituents which were thus identified in this oil, four deserve a particular mention, namely, thecis‐3‐methyldec‐3‐en‐1‐ol (I), the related acid III, thetrans‐3‐methyl‐dec‐4‐enoic acid (IV), and the homoterpene lactone dihydroactinidiolide (II). With the exception of the last one, these unusual C11compounds play a prominent role in the characteristic fr

ISSN:0018-019X    

DOI:10.1002/hlca.19690520104

出版商:WILEY‐VCH Verlag GmbH    

年代:1969

数据来源: WILEY

摘要:

AbstractThe «dimeric» indole alkaloid (+)‐pycnanthine (2) has been isolated, along with (+)‐pleiocarpamine, (+)‐quebrachamine, (+)‐macusine B and an unknown alkaloid D fromPleiocarpa pycnantha(K. SCHUM.) STAPF,var. pycnanthaM. PICHON.An investigation of its chemical and spectroscopic properties has led to the determination of structure2for this base. Its 6′,7′‐dihydro derivative has been shown to be identical with the alkaloid pleiomutinine, previously isolated fromPleioca

ISSN:0018-019X    

DOI:10.1002/hlca.19690520105

出版商:WILEY‐VCH Verlag GmbH    

年代:1969

数据来源: WILEY

摘要:

AbstractThe value of the nuclcear‐spin‐coupling‐constantJ1H‐199Hgof methylmecury compounds CH3HgL is related to:1(a) the electrode potential for oxidative dimerisation of L,1(b) the interatomic distances C‐Hg in CH3HgL,1(c) the interatomic distances Hg‐Hg in L‐Hg‐Hg‐L,1(d) the energy of dissociation of CH3HgL into CH3and HgL,1(e) the logarithms of the stability constants of CH3HgL,1(f) the logarithms of the relative nucleophilic reactivites of L inSN2reactions at a saturated carbon atom1(g) the proton‐bascicity of L (in series of structurally similar ligands, possessing the same ligating atom, as for example carboxylate anions).Approximately linear correlations were found betweenJ1H‐199Hgand the values of (a), (e), (f), and (g). It is suggested that the value of the nuclear‐spin‐spin‐coupling‐constantJ1H‐199Hgof CH3HgL provides a measure of the relative energy of the occupied fronti

ISSN:0018-019X    

DOI:10.1002/hlca.19690520106

出版商:WILEY‐VCH Verlag GmbH    

年代:1969

数据来源: WILEY

摘要:

AbstractThe three ternary limiting isotherms of the system KCI‐RbCI‐CsCI‐H2O are given for 25°. The system KCI‐RbCI‐H2O, with only one solid phase present, belongs to the type I of the ROOZEBOOMclassification. A large miscibility gap is present in the systems RbCI‐CsCI‐H2O and KCI‐CsCI‐H2O; in the latter the incorporation is almost negligible; they belong to R

ISSN:0018-019X    

DOI:10.1002/hlca.19690520107

出版商:WILEY‐VCH Verlag GmbH    

年代:1969

数据来源: WILEY

摘要:

AbstractA new chemical degradation of (–)‐kopsine is described which completely confirms the structure of this alkaloid. Correlation of (–)‐aspidofractinine, (–)‐pleiocarpine and (–)‐kopsine with (–)‐minovincine establishes the absolute stereochemistry of these bases. It appears that, in contrast to the aspidospermine group, all alkaloids containing the aspidofractinine skeleton possess the same absol

ISSN:0018-019X    

DOI:10.1002/hlca.19690520108

出版商:WILEY‐VCH Verlag GmbH    

年代:1969

数据来源: WILEY

摘要:

AbstractUmbellamine (f; C41H48N4O4), a «dimeric» indole‐indoline alkaloid, was isolated from the root bark ofHunteria umbellata(K. SCHUM.) HALL. F.; it is probably identical with the alkaloid hunterine (structure unknown) of NeUSS&CONE[14]. Thermolysis yielded (+)‐eburnamenine (II), whereas a detailed mass spectrometric study of I, of its O‐methyl and O‐acetyl derivatives, and also of the derived diol V revealed the presence of a phenolic hydroxy‐pseudoakuammigine group as second part, the benzene nucleus of the latter being linked to the C‐14 atom of the eburnamenine component (present in the dihydrom form).The n.m.r. study of umbellamine and of its derivatives showed that the phenolic hydroxy group is either at C‐10′ or C‐11′ and that the dihydroeburnamenyl residue is connected to C‐11′ or C‐10′ of the pseudoakuammigine residue. A choice between these alternatives was possible by investigation of the hydroxylated base IX arising from the latter component, and obtained in small quantities by treatment of umbellamine with zinc or tin in acid. Its constitution, deduced by uv., n.m.r. and mass spectrometry, suggested that the hydroxy group is fixed at C‐11′. If this is correct, the dihydrocburnatnenyl residue is linked to C‐10′ of the pseudoakuarnmigine residue. Thus

ISSN:0018-019X    

DOI:10.1002/hlca.19690520109

出版商:WILEY‐VCH Verlag GmbH    

年代:1969

数据来源: WILEY

摘要:

AbstractThe13C NMR. spectra of seventeenm‐ andp‐ subsituted benzonitriles were examined and partially anlayzed. The C‐1 carbon shieldings can be expressed in terms of a linear correlation with the LCAO‐MO‐π‐electron density at C‐1. No such correlation was found for the cyanocarbon, whose electron density shows only slight varriations for the different substitutents. This fact is consistent with the relatively small range of the chemical shifts

ISSN:0018-019X    

DOI:10.1002/hlca.19690520110

出版商:WILEY‐VCH Verlag GmbH    

年代:1969

数据来源: WILEY

摘要:

AbstractEs wird über Darstellung und spektroskopische Untersuchungen von Kupfer (II)‐Komplexen CuL2X2und CuL4X2mit grösstenteils unidentaten Stickstoffbasen berichtet. Durch Ausnützung der Einflüsse von Substitutenten am Pyridin‐ bzw. Piperidinring der Liganden L wurden Komplexe verschiedener Stereometrie erhalten, an denen sich der Zusammenhang zwischen Mikrosymmetrie und Elektronenspektren studieren liess. Insbesondere konnte die Stauchung eines pseudotetraedrischen Teilchens über eine Reihe von Zwischenstufen bis zur planaren Anordnung der 4 Ligandatome anhand einer Anzahl von Verbindungen des Type CuL2X2verfolgt werden. Die Arbeit befasst sich dabei im wesentlichen mit den Ligandenfeldspektren (über die Elektronentransfer‐Übergange sol1 später berichtet werden). Der letzte Ligandenfeldübergang tritt bei den planaren Komplexen ‐ offenbar wegen. Abschirmung des Zentral‐Ions vor Störungen längs derz‐achse bei unerwa

ISSN:0018-019X    

DOI:10.1002/hlca.19690520111

出版商:WILEY‐VCH Verlag GmbH    

年代:1969

数据来源: WILEY