摘要:

AbstractThe reaction of Co(C5H5)2with tertiary phosphites mainly gives the half‐sandwich type compounds C5H5Co[P(OR)3]2(R = CH3, C2H5, C6H5), which are characterised by means of their IR., UV., and NMR. spectroscopic data. The mass spectra of the new compounds are discusse

ISSN:0018-019X    

DOI:10.1002/hlca.19710540102

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractDie vor kurzem beschriebenen 6‐Trichlormethyl‐2‐pyrone wurden mit Zink und mit komplexen Metallhydriden reduziert. 6‐Trichlormethylpyron (15) und drei an C4 verschieden alkylierte Derivate (5, 16und17) ergaben mit Zink in Eisessig die entsprechenden 6‐Methyl‐2‐pyrone18, 1, 19und20. Im Falle des 6‐Trichlormethyl‐4‐(4′‐methyl‐pent‐3′‐en‐yl)‐2‐pyrans (17) bildete sich auch 3,8,8‐Trimethyl‐5,6,7,8‐tetrahydro‐isocumarin (21).Die komplexen Metallhydrid‐Reduktionen wurden am Beispiel des 6‐Trichlormethyl‐4‐methyl‐2‐pyron (5) untersucht. Mit Natriumborhydrid in Äthanol entstanden 6‐Dichlormethyl‐4‐methyl‐2‐pyron (6, 14%) und 6,6,6‐Trichlor‐3‐methyl‐hex‐3‐en‐1, 5‐diol (7, 37%). Mit Lithiumaluminiumhydrid in Tetrahydrofuran erhielt man 6‐Chlor‐ (10, 47%) und 6,6‐Dichlor‐3‐methyl‐hexa‐3,5‐dien‐1‐ol (9, 19%). Für diese Hydridreduktionen wird ein Mechanismus v

ISSN:0018-019X    

DOI:10.1002/hlca.19710540103

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractFrom the leaves of the African ApocynaceaPleiocarpa talbotii Wernhama novel indole alkaloid, talbotine, C21H24N2O4, has been isolated. Talbotine (1) contains a secondary N(b)‐atom and a cyclic hemiacetal group. Catalytic hydrogenation leads to 19, 20‐dihydrotalbotine (6), hydrogenation in the presence of formaldehyde gives N(b)‐methyl‐19, 20‐dihydrotalbotine (8). In the presence of sodium methoxide and methanol,1is converted into the lactone12and the methyl ester13. In these reactions carbon 17 is lost as formic acid. These data, together with the analyses of the NMR. spectra of talbotine and its derivatives as well as the interpretation of the various types of the mass spectral fragmentation, lead to formula1for the alkaloid.Dehydrogenation of talbotine methyl ether (3) with palladium and maleic acid gives the ß‐carboline derivative26. The N(b)‐methiodide of the latter is converted into N(b)‐methyl‐talbotine methyl ether on reduction with sodium borohydride. From these data as well as from the analyses of NMR. and IR. spectra the complete relative stereochemistry of talbotine could be derived. Application of theHoreaumethod to the nitrogen atom b of the methyl ether3on the one hand and to the hydroxyl group on C17 in N(b)‐methyl‐19, 20‐dihydrotalbotine (8) on the other hand gives consistent results and establishesSco

ISSN:0018-019X    

DOI:10.1002/hlca.19710540104

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractBy conventional methods a mixture of diastereomeric 2,4, 6‐trimethylpimelic acids was prepared and separated by counter‐current distribution. The twomeso‐compounds were isolated in crystalline form, one of them (m.p. 130°) giving a dimethyl ester identical with a degradation product of the antibiotic borrelidin. The chirality (2‐R,4‐r,6‐S) of the acid of m.p. 130° was determined by an X‐ray structural analysis (see f

ISSN:0018-019X    

DOI:10.1002/hlca.19710540105

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe crystal structure of the stereoisomer m.p. 130° of 2,4,6‐trimethylpimelic acid has been determined by three‐dimensionalX‐ray analysis. The cristals are monoclinic,a= 10.35,b= 10.70,c= 11.61 Å, β = 110°12′,Z= 4, space groupP2 1/c, the structure has been solved by direct methods and refined by least‐squares methods.The configuration of the acid is given by formula I; the chirality of the asymmetric centres is (2

ISSN:0018-019X    

DOI:10.1002/hlca.19710540106

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractA convenient method is given for the semiquantitative determination of those changes ΔSiin internal coordinates, which describe the structure of the radical cationM+(Ψ) relative to the neutral moleculeMin its electronic ground state. The changes ΔSicorrespond to those associated with the relaxation process which follows the ionisationM+hv→M+(Ψ) +e,M+being in the electronic state Ψ. The method, based on the procedure originally developped bySmith&Warsop[3], uses the spacing and relative intensity of the vibrational fine‐structure components of the bands in the photoelectron spectrum ofM.From these data are calculated the changes ΔQkin normal coordinates, which are then transformed into the ΔSiby applying theL‐matrix.The changes ΔRCX, ΔRCCand ΔRCHwhich describe the structure of the radical cations of the four monohaloacetylenesI(X) (X = F, Cl, Br, I) in their2IIΩ(1) and2IIΩ(2) states have been determined. It is shown that the results are in agreement with theoretical expectation and that they confirm the band assignement proposed in a previous

ISSN:0018-019X    

DOI:10.1002/hlca.19710540107

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe crystal and molecular structure of nickel(II)‐1, 8, 8, 13, 13‐pentamethyl‐5‐cyano‐trans‐corrin chloride has been determined by X‐ray analysis. The shape and dimensions of the corrin nucleus are discussed i

ISSN:0018-019X    

DOI:10.1002/hlca.19710540108

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractAn X‐ray crystal structure analysis of the perchlorate salt of the C/D‐seco‐corrinoid nickel(II) complex I is reported. The structural transformations that occur in the base‐catalysed iminoester‐enamine condensation of I leading to the corrin complex II are

ISSN:0018-019X    

DOI:10.1002/hlca.19710540109

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractX‐ray crystal structure investigations of the isomorphous perchlorate salts of complexes of an A/D‐seco‐corrinoid ligand (I) with divalent nickel, palladium and platinum are reported. The structures determined for the Pd‐ and Pt‐complexes are virtually superposable, that of the Ni‐complex, although similar to the other two, shows significant differences with respect to metal coordination and to the spatial relationship of the A and D rings and their substituents. These similarities and differences are discussed in relation to the photochemical A/D cyclization leading to corrin com

ISSN:0018-019X    

DOI:10.1002/hlca.19710540110

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractA series of new N‐(ω‐aryloxyalkyl) piperidinium, pyridinium, benzyl dimethyl ammonium, and trimethyl ammonium bromides is descr

ISSN:0018-019X    

DOI:10.1002/hlca.19710540111

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY