ISSN:0018-019X    

DOI:10.1002/hlca.19790620302

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Fluorenone Derivatives. IX. 3‐(Pyrid‐2‐yl)‐fluorenone, 2‐methyl‐3‐(pyrid‐2‐yl)‐fluorenone, and 2‐(3‐methyl‐pyrid‐2‐yl)fluorenoneUnsuccessful attempts to synthesize an aza‐cis‐fluorenacene system starting from 2‐aza‐chalcone or 6‐methyl‐

ISSN:0018-019X    

DOI:10.1002/hlca.19790620303

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Abstract15N‐NMR. parameters for the complexestrans‐[MCl2(15NH2(CH2)5CH3)L] are reported; M = Pt, Pd, L = PBu n3, PMePh2, P (p‐CH3C6H4)3, AsBun3, AsMePh2, As (p‐CH3C6H4)3, NH2(CH2)5CH3and (for Pt) C2H4. For both metals, the NMR. parameters depend on thetrans‐influence of the ligand L. The values1J(195Pt,15N) vary from 138 to 336 Hz and can be shown to correlate with the values1J(195Pt,31P) in the complexestrans‐[PtCl2(PBu n3)L]. There is a linear relation between the15N chemical shifts in the complexes of the two metals. The reactions of the complexessym‐trans‐[M2Cl4L2], M = Pd, Pt, L = a tertiary phosphine or arsine, with neutral ligands are described.195Pt‐,31P‐ and1

ISSN:0018-019X    

DOI:10.1002/hlca.19790620304

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractSeveral naturally occurring xanthone‐1‐O‐glycosides have been synthesized in order to study monoamine oxidase (MAO) inhibition structure‐activity relationships. The syntheses also confirmed the structures as 1‐β‐D‐glucosyloxy‐3‐hydroxy‐5‐methoxyxanthone (Canscora decussataSCHULT.), 1‐O‐β‐primeverosyl‐3, 7, 8‐trimethoxyxanthone (decussatin‐1‐O‐primeveroside,Gentiana vernaL.) and 1‐O‐β‐primeverosyl‐3, 8‐dimethoxy‐7‐hydroxyxanthon

ISSN:0018-019X    

DOI:10.1002/hlca.19790620305

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractThe complexone‐like tetraazamacrocycle1(LH4) forms a series of metal complexes with Co2+, Ni2+, Cu2+and Zn2+(M2+) of the type MLH2, ML2−and M2L, which have been isolated and characterized by VIS., IR. and NMR. spectroscopy. Based on these results tentative structures for the different species are propo

ISSN:0018-019X    

DOI:10.1002/hlca.19790620306

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Synthesis and enzymatic deamination of 3′‐C‐hydroxymethyl‐ and 3′‐C‐methyl‐β‐D‐xylofuranosyl‐9‐adeninesThe title compounds have been prepared by classical synthetic steps after having optimized the nature of the blocking groups. Both nucleosides were found to be substrates of adenosine aminohydrolase which proved that C(3′)‐branched‐chain sugar nucleosides can be deaminated when the branched‐chain isexo(transrelative to the base) if a suitably disposed hydroxy group is available on

ISSN:0018-019X    

DOI:10.1002/hlca.19790620307

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Further examples ofO‐isopropylidenaldehydosugars in the furanose seriesFormyl‐bearing furanose derivatives1–3(α‐D‐xyloor α‐D‐erythroconfigurations) and5–8(configurations α‐D‐ribo, α‐D‐lyxo, β‐L‐threoandD‐arabino) have been prepared by classical synthetic steps and their properties mainly spectroscopic, reported. The coupling constant between the formyl and the vicinal proton is always small. Like other members of the series, these new aldehydosugars constitute very useful an

ISSN:0018-019X    

DOI:10.1002/hlca.19790620308

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractThe processes involved in photoenolisations are theoretically simulated by anab initioSCF‐CI method, usingcis‐2‐butenal as a prototype structure. The prominent role of the hydroxyl group conformation in the resulting transient (2a) is emphasized; its rotation ‘out of the reaction site’ allows the next reaction paths to proceed exothermally. The equilibration of the different types of twisted biradicals in the triplet manifold, which only involves a low energy barrier, is thus possible, populating in quite equal weights the precursors of bothE‐ andZ‐dienols. In the singlet state, the formation of the Z‐isomer is expected to be kinetically dominant. An examination of the role of the substituents suggests that, in related systems, the steric crowding induces important structural relaxation of the di

ISSN:0018-019X    

DOI:10.1002/hlca.19790620309

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Identification and synthesis of new depsides isolated from oakmoss (Evernia Prunastri(L.)ACH.)Lecanoric acid5and 4 new depsides have been isolated from oakmoss (Evernia Prunastri(L.)ACH.) extracts by means of silicagel column chromatography. Various spectral methods including13C‐NMR. were used in determining the structure of 4,2″‐O‐methylgyrophoric acid (1), lecanoric acid (5), 2′‐O‐methylevernic acid (2), 3′‐methylevernic acid (3) and methyl 3′

ISSN:0018-019X    

DOI:10.1002/hlca.19790620310

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Attempted Synthesis of Nonafulvenes and of NonaheptafulvaleneThe reaction of cyclononatetraenide with α‐bromobenzyl acetate (6) as well as with 1,1‐dihalodimethylether gives at −50°, instead of the expected cyclononatetraenes, bicyclo[6.1.0]nona‐2,4,6‐triene derivatives10dand16(Scheme 3and5, respectively). It seems that in some cases the well known thermally disrotative valence isomerization of cyclononatetraenes7to 3a, 7a‐dihydroindenes8is much slower than the formation of bicyclo[6.1.0]nona‐2,4,6‐trienes of the type10and16. This type of reaction hurts theWoodward‐Hoffmannrules.Possible precursors of the attractive nonaheptafulvalene are prepared by reaction of acetoxy‐tropylium fluoborate (19a) as well as of bromo‐tropylium bromide (19b) with lithium‐cyclononatetraenide(Scheme 8). So far, the attempted gas‐phase pyrolysis of the precursors21aand21bfailed to

ISSN:0018-019X    

DOI:10.1002/hlca.19790620311

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY