摘要:

AbstractWhen (−)‐Δ8‐6a, 10a‐trans‐THC (THC = Tetrahydrocannabinol), in the form of its diacetate, was irradiated in the presence of oxygen and a sensitizer, followed by reduction with NaBH4, three allylic alcohols were formed: (−)‐8α‐and (−)‐8β‐hydroxy‐Δ9,11‐THC (proportion 3:1) and (−)‐9α‐hydroxy‐Δ7,8‐THC. Acetylation of the epimeric 8‐hydroxy‐compounds with Ac2O/pyridine gave the corresponding diacetates.When (−)‐Δ8‐6a, 10a‐trans‐THC, in the form of its tetrahydropyranyl derivative, was heated withm‐chloroperbenzoic acid, the two epimeric 8,9‐epoxides were formed in equal amounts. These compounds, on treatment with butyllithium, afforded (−)‐8α‐ and (−)‐8β‐hydroxy‐Δ9,11‐ 6a, 10a‐trans‐THC‐tetrahydropyranylether. After removing the protecting group and treatment with Ac2O/pyridine the same diacetates, as formed by photooxygenation of (−)‐Δ8‐THC‐acetate, were obtained as a 1:1‐mixture.On heating these epimeric diacetates to 290° they underwent allylic rearrangement to (−)‐11‐acet

ISSN:0018-019X    

DOI:10.1002/hlca.19740570112

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractThe PE. spectra of [2, 2]paracyclophane (1), 4‐amino[2, 2]paracyclophane (2) and 1, 1, 2, 2, 9, 9, 10, 10‐octafluoro[2, 2]paracyclophane (3) are presented. The bands corresponding to ejection of the photoelectron from the five highest occupied π‐orbitals have been assigned. The ‘observed’ orbital energies (i.e.the negative ionization potentials) are discussed in terms of ‘through space’ and ‘through‐bond’ interactions between the semi‐localized π‐orbitals (e1g) of the benzene moieties and the C, C‐σ‐orbitals of the ethylene bridges.The PE. spectrum of3shows that the fluorine‐induced lowering of the C, C‐σ‐orbital energy effectively ‘turns‐off’ the ‘through‐bond’ interaction. The resulting pattern of the first four bands confirms the assignment given for1.Finally the band shifts induced by an amino group in position 4 are again in agreement with this assignment. Attention is drawn to the phenomenon of ‘orbital switching’ as a consequenc

ISSN:0018-019X    

DOI:10.1002/hlca.19740570113

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractDie Eigenschaften des Magnesiumsalzes der 5‐Methyltetrahydrofolsäure und eine spezifische Methode zu seiner quantitativen Bestimmung werden beschrieben. Die Stabilitäten der Na‐, Mg‐, Ca‐, Ba‐Salze werden vergleichend

ISSN:0018-019X    

DOI:10.1002/hlca.19740570114

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractAn improved one‐step synthesis of the title compound is described, the optical activity of the natural product is confirmed, and the NMR. spectral behaviour is explaine

ISSN:0018-019X    

DOI:10.1002/hlca.19740570115

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractThe preparation of 2.5‐diphenyl‐1‐silacyclopentadienes and their reaction with iron carbonyls and π‐cyclopentadienyl‐dicarbonylcobalt yielding metal‐π‐silole complexes is described. Mass spectral data indicate the existence of an ‘aromatic’ silacyclo

ISSN:0018-019X    

DOI:10.1002/hlca.19740570116

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractA four step synthesis of Seychellene (1) is described. IntramolecularDiels‐Alderreaction of dienon2furnished the tricyclic ketones3and4in good yield. Hydrogenation of3gave5and6. The higher reactivity of6with methyllithium compared to5allowed the selective preparation of8, which, on subsequent acid‐catalyzed rearrangment afforded Seychellen in 57,5% yield. In an analogues manner epi‐Seychellene was synthetizedviathe intermediates

ISSN:0018-019X    

DOI:10.1002/hlca.19740570117

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractThe catalytic hydrogenation in acidic solution (pH ∼ 2) of the title compoundIn order to represent this and the related compounds by meaningful abbreviations, we shall adopt the numerotation system proposed in the literature [8] [12]. The complete abbreviation of the title compound is [Ni(5, 7, 7, 12, 14, 14‐Me6‐[14]‐4, 11‐diene‐1, 4, 8, 11‐N4)]2+. As in the present work the 14‐membered ring system with six methyl groups remains unchanged, we shall use [Ni(4, 11‐dieneN4)]2+and [Ni(4, 11‐aneN4)]2+and [Ni(4, 11‐aneN4)]2+for the complex with the unsaturated and saturated ligand, respectively.[Ni(4, 11‐dieneN4)]2+(I) has been studied. The reaction yields only C‐meso‐ 5, 7, 7, 12, 14, 14‐hexa‐methyl‐1, 4, 8, 11‐tetraaza‐cyclotetradecane‐nickel (II) (C‐meso‐[Ni(4, 11‐aneN4)]2+), whenmeso‐[Ni(4, 11‐dieneN4)]2+is the starting material. Rac‐[Ni(4, 11‐dieneN4)]2+yields the unstable α‐C‐rac‐[Ni(4, 11‐aneN4)]2+. When optically active [Ni(4, 11‐dieneN4)]2+is reduced, optically active α‐[Ni(4, 11‐aneN4)]2+is obtained, which in neutral or basic solution shows mutarotation due to conversion into optically active β‐[Ni(4, 11‐aneN4)]2+no racemization is observed. Reaction with cyanide ions yields the optically active free tetrami

ISSN:0018-019X    

DOI:10.1002/hlca.19740570118

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractThe crystal structure of synthetic, racemic ψ‐retroprogesterone (9α‐methyl‐19‐nor‐progesterone) has been determined by X‐ray analysis and refined to R = 0.050. The analysis was carried out to establish the relative configuration at positions 9, 10 and 17 in connection with the biological activity of

ISSN:0018-019X    

DOI:10.1002/hlca.19740570119

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

ISSN:0018-019X    

DOI:10.1002/hlca.19740570120

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

Abstract1, 4‐Dicyanobicyclo[2.2.0]hexane (2) was prepared by (2+2)‐photocycloaddition of ethylene to 1, 2‐dicyanocyclobutene.2isomerizes cleanly to 2, 5‐dicyanohexadiene‐1, 5 (3) with a very low activation energy of 21.7 ± 1.4 kcal/mol. From comparison with the reported rates of isomerization of bicyclo[2.2.0]hexane, the radical stabilization energy of the cyano group is shown to be about 7.

ISSN:0018-019X    

DOI:10.1002/hlca.19740570121

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY