摘要:

AbstractThe syntheses of 4‐chloro‐1‐dimethylamino‐4‐methyl‐pentane (1) and 4‐chloro‐1‐dimethylamino‐2,2,4‐trimethyl‐pen

ISSN:0018-019X    

DOI:10.1002/hlca.19670500202

出版商:WILEY‐VCH Verlag GmbH    

年代:1967

数据来源: WILEY

摘要:

AbstractFlavohydroquinones (leucoflavins) protected by acetylation at N(5) have been alkylated to give derivatives substituted at oxygen and/or nitrogen functions in the pyrimidine part of the nucleus. Removal of the protecting group under oxidizing conditions gave N(1),N(3)‐, O(2),N(3)‐ or O(2), O(4)‐dialkyl‐flavoquinonium salts. The N(1)‐substituted type could be reduced to give free flavohydroquinones stable in air, which in turn could be further alkylated at N(5). On oxidation the N(5)‐alkyl groups are readily removed through the radical intermediate. The N(10)‐alkyl groups may be split from the flavoquinonium salt if they are activated (e. g. ‐CH2COOR). The O‐alkyl groups are readily hydrolysed under neutral or slightly acid conditions whereas a basic medium provokes deprotonation at the 8‐CH3group and concomitant irreversible dimerization. The potential importance of these models for elucidating the mechanism of flavin‐dependent biological dehydro

ISSN:0018-019X    

DOI:10.1002/hlca.19670500203

出版商:WILEY‐VCH Verlag GmbH    

年代:1967

数据来源: WILEY

摘要:

AbstractPyridoxine and pyridoxal are suitable for gas‐chromatographic analysis after conversion into their trimethylsilyl derivatives. Silylation proceeds rapidly and quantitatively, pyridoxal reacting in its hemiacetal form. The mass spectra of both derivatives are discusse

ISSN:0018-019X    

DOI:10.1002/hlca.19670500204

出版商:WILEY‐VCH Verlag GmbH    

年代:1967

数据来源: WILEY

摘要:

AbstractIn continuation of previous work, the behaviour of amino‐anthraquinones on fusion in pyridine ‐ aluminium chloride in the presence of oxidants is studied. Instead of dimerisation the reaction leads to salts of pyridinio‐aminoanthraquinones and further to condensed “anthraimidazopyridine” de

ISSN:0018-019X    

DOI:10.1002/hlca.19670500205

出版商:WILEY‐VCH Verlag GmbH    

年代:1967

数据来源: WILEY

摘要:

AbstractUsing suitably deuteriated olefins, it is shown that electron bombardment of compounds having double bonds exocyclic to six‐membered rings apparently causes migration of the double bond into the ring. Isopropenylcyclohexanes, on the other hand, appear to behave as if the radical were fixed on the terminal carbon, while the charge migrates by 1,2 hydrogen transfer

ISSN:0018-019X    

DOI:10.1002/hlca.19670500206

出版商:WILEY‐VCH Verlag GmbH    

年代:1967

数据来源: WILEY

摘要:

AbstractThe adducts of benzoic,p‐toluic, mesitoic and cinnamic acids with SbCl5, AlCl3, TiCl4, SnCl4and ZnCl2have been prepared, and the IR. absorption spectra of the compounds, in the solid state or in solution in CCl4, studied. The lowering of the carbonyl frequency shows that the acceptor is linked by a dative bond to the carbonyl oxygen atom acting as donor. A calculation, by the Wilson GF method, of force constants and their contributions in potential energy of vibration for monomeric benzoïc acid and its adduct with TiCl4confirmed that the carbonyl stretching force constant, and therefore the CO bond order, is lowered by the formation of the add

ISSN:0018-019X    

DOI:10.1002/hlca.19670500207

出版商:WILEY‐VCH Verlag GmbH    

年代:1967

数据来源: WILEY

摘要:

AbstractDurch Synthesen mit Kieselgel und H3PO4bei verschiedenen Temperaturen, bzw. mit Kieselgel und P2O5, wurden Silicophosphorsäure H2Si(PO4)2, eine Verbindung 3 SiO2, 2P2O5und vier polymorphe Modifikationen von SiO2, P2O5, welche als Formen I‐IV bezeichnet wurden, erhalt

ISSN:0018-019X    

DOI:10.1002/hlca.19670500208

出版商:WILEY‐VCH Verlag GmbH    

年代:1967

数据来源: WILEY

摘要:

AbstractThe analysis of measurements of the thermal diffusion factor α in the systems H35Cl/H37Cl, D35Cl/D37Cl and H35Cl/D35Cl shows that α may be approximated by the expression α = C_m \frac{{m_1 − m_2 }}{{m_1 + m_2 }} + C_\theta \frac{{\theta _1 − \theta _2 }}{{\theta _1 + \theta

ISSN:0018-019X    

DOI:10.1002/hlca.19670500209

出版商:WILEY‐VCH Verlag GmbH    

年代:1967

数据来源: WILEY

摘要:

AbstractBy oxydation of N(5)‐methyl‐6,7‐diphenyl‐5,6‐dihydro‐ and N(5)‐methyl‐6,7‐diphenyl‐5,6,7,8‐tetrahydro‐pterine derivatives with perhydrol 8‐monohydro‐ and 6,7,8‐trihydro‐pteridine radical cations are produced which are sufficiently stable for detection and structural elucidation by ESR. hyperfine analysis. The biological implications of these radicals for pteridine dependent hydroxylation and methyl transfer from 5

ISSN:0018-019X    

DOI:10.1002/hlca.19670500210

出版商:WILEY‐VCH Verlag GmbH    

年代:1967

数据来源: WILEY

摘要:

AbstractIn a heterolytic fragmentation reaction of the typea‐b‐c‐d‐X→a‐b+c=d+ :Xthe geometry of thed‐Xbond and that of the electron‐donating grouparelative to theb‐cbond are critical. This follows from a study of solvolysis rates and products of stereoisomeric 1‐methyl‐4‐, ‐5‐ and ‐7‐decahydroquinolylp‐tolue

ISSN:0018-019X    

DOI:10.1002/hlca.19670500211

出版商:WILEY‐VCH Verlag GmbH    

年代:1967

数据来源: WILEY