摘要:

Photochemistry of ε,ζ‐Methano‐α,γ‐dienones and 7,8‐Methano‐1,3,5‐trienesIrradiation of the δ‐cyclopropyl‐dienone (E)‐6(λ ≥ 347 nm) gives (Z)‐6, 10(1,5‐sigmatropic H‐shift), (E/Z)‐9(electrocyclic process involving C(ε), C(ζ)‐cleavage) and11(ring opening).The corresponding 6‐cyclopropyl‐triene (E)‐7gives on singlet excitation (δ>280 nm)14(1,5‐sigmatropic H‐shift) and, to a smaller extent, the bicyclo [3.2.0] heptenyl‐dienes (E/Z)‐13. However, on triplet excitation (λ ≥ 347 nm, benzophenone) (E)‐7gives (E/Z)‐13as the main products. On both1π,π

ISSN:0018-019X    

DOI:10.1002/hlca.19810640502

出版商:WILEY‐VCH Verlag GmbH    

年代:1981

数据来源: WILEY

摘要:

AbstractEasily accessible dihydropyrans9, 10, 12and19are precursors for the synthesis of 6‐substituted 5,6‐dihydro‐2 (2H)‐pyranones and 6‐substituted tetrahydro‐2‐pyranones. Syntheses of massoia lactone (3), argentilactone (5), tuberolactone (4) and jasmine lactone (2) from acrolein (6), acrolein dimer (7) or glutaraldehyde (16)

ISSN:0018-019X    

DOI:10.1002/hlca.19810640503

出版商:WILEY‐VCH Verlag GmbH    

年代:1981

数据来源: WILEY

摘要:

Synthesis of Diastereo‐ and Enantioselectively Deuterated β,ε‐, β,β‐, β,γ‐ and γ,γ‐CarotenesWe describe the synthesis of (1′R, 6′S)‐[16′, 16′, 16′‐2H3]‐β, εcarotene, (1R, 1′R)‐[16, 16, 16, 16′, 16′, 16′‐2H6]‐β, β‐carotene, (1′R, 6′S)‐[16′, 16′, 16′‐2H3]‐γ, γ‐carotene and (1R, 1′R, 6S, 6′S)‐[16, 16, 16, 16′, 16′, 16′‐2H6]‐γ, γ‐carotene by a multistep degradation of (4R, 5S, 10S)‐[18, 18, 18‐2H3]‐didehydroabietane to optically active deuterated β‐, ε‐ and γ‐C11‐endgroups and subsequent building up according to schemes\documentclass{article}\pagestyle{empty}\begin{document}${\rm C}_{11} \to {\rm C}_{14}^{C_{\mathop {26}\limits_ \to }} \to {\rm C}_{40} $\end{document}and C11→ C14; C14+C12+C14→C40.NMR.‐ and chiroptical data allow the identification of the geminal methyl groups in all these compounds. The optical activity of all‐(E)‐[2H6]‐β,β‐carotene, which is solely due to the isotopically different substituent not directly attached to the chiral centres, is demonstrated by a significant CD.‐effect at low temperature. Therefore, if an enzymatic cyclization of [17, 17, 17, 17′, 17′, 17′‐2H6]lycopine can be achieved, the steric course of the cyclization step would be derivable from NMR.‐ and CD.‐spec

ISSN:0018-019X    

DOI:10.1002/hlca.19810640504

出版商:WILEY‐VCH Verlag GmbH    

年代:1981

数据来源: WILEY

摘要:

AbstractThe13C‐NMR. spectra of the series of complexes η6‐naphthalene · CrL3(LCO (1), PF3(2), PF2OMe (6), P(OMe)3(3), C10H8(= 3 L) (4) and PMe3(5)) are reported. Definite assignments of the13C‐NMR. resonances were made through the synthesis of [2, 3, 6, 7‐2H4]‐naphthalene complexes. The coordinated ring13C‐resonance are found to undergo a smooth transition to higher field with increasing donor character of the coligands L. A correlation of the coordination shifts with the reactivity of the coordinated naphthalene is proposed. In complexes containing strong acceptor ligands the naphthalene is activated to attack by nucleophiles. Sequential treatment of complexes1–4,6and [C10H8FeC5H5]+[PF6]−(7) with stabilized carbanions and I2or Ce(IV)‐salt yields α‐substituted naphthalenes in the case of1,2,6and7but not in the case of3and4. Treatment of3with an excess of HBF4results not in the expected metal protonation but in a novel ligand

ISSN:0018-019X    

DOI:10.1002/hlca.19810640505

出版商:WILEY‐VCH Verlag GmbH    

年代:1981

数据来源: WILEY

摘要:

AbstractThe antinociceptive potency and receptor affinity of several optically active aromatic mono‐ and di‐oxygenatedN‐methylmorphinans andN‐methylmorphinan‐6‐ones, prepared from natural morphine, were determined. Thus, in order of antinociceptive potency, 4‐methoxy‐N‐methylmorphinan‐6‐one ≈ 3,4‐dimethoxy‐N‐methylmorphinan‐6‐one ≈ 3,4‐dimethoxy‐N‐methylmorphinan>4‐methoxy‐N‐methylmorphinan ≈ 4‐acetoxy‐N‐methylmorphinan‐6‐one>4‐acetoxy‐N‐methylmorphinan ≈ 4‐hydroxy‐N‐methylmorphinan‐6‐one ≈ 4‐hydroxy‐N‐methylmorphinan. The 4‐hydroxy compounds were slightly less potent than morphine, and the 4‐methoxy and 3,4‐dimethoxy compounds were found to have three times the potency of morphine. 4‐Methoxy‐N‐methylmorphinan‐6‐one showed an opiate recepto

ISSN:0018-019X    

DOI:10.1002/hlca.19810640506

出版商:WILEY‐VCH Verlag GmbH    

年代:1981

数据来源: WILEY

摘要:

AbstractSelective formation ‐ in intramolecularWittigcondensations ‐ of the 2‐oxocephem‐4‐carboxylate8aand of the 2‐acetylpenem‐3‐carboxylate9, respectively, was observed as a consequence of different carbonyl reactivities in two homologous α‐oxoacylthio groupings. Free, racemic and 7‐unsubstituted 2‐oxocephem‐4‐carboxylic acid (10) was prepared from8afor biological testing. Attempts to prepare the free 2‐acetylpenem‐3‐carboxylic acid from9failed, probably due to the high

ISSN:0018-019X    

DOI:10.1002/hlca.19810640507

出版商:WILEY‐VCH Verlag GmbH    

年代:1981

数据来源: WILEY

摘要:

AbstractThe photoelectron (PE.) spectra of 1,2,3‐methenoindane (2), 1,2,3‐metheno‐2,3‐dihydro‐1H‐cyclopenta [b]naphthalene (3) and 1,2,3‐metheno‐2,3‐dihydro‐1H‐phenalene (4) are investigated. The PE. spectrum of 1,3‐methano‐2,3‐dihydrophenalene (7) is reported and compared with that of4. The experimental results are analyzed in terms of empirical correlation diagrams and the results of semiempirical MINDO/3 and CNDO/S calculations. The analysis indicates that the strong impact of the bicyclobutylene group on the spectroscopic properties of the aromatic π‐systems in2,3and4is due to hyperconjugative interactions involv

ISSN:0018-019X    

DOI:10.1002/hlca.19810640508

出版商:WILEY‐VCH Verlag GmbH    

年代:1981

数据来源: WILEY

摘要:

From a Base Catalyzed Ring Opening of 2H‐Azirines to an α‐Alkylation Method of Primary AminesIt is shown that fluorene‐9′‐spiro‐2‐(3‐phenyl‐2H‐azirine) (1) on treatment with various alcohols in the presence of the corresponding alkoxide ions yieldsN‐(9′‐fluorenyl)benzimidates2a‐d(Scheme 1). 2,2,3‐Triphenyl‐2H‐azirine (3) reacts with methanol in a similar manner(Scheme 2). Benzimidates2a(Scheme 3),8(Scheme 4)and and10(Scheme 5)can easily be deprotonated by butyllithium (BuLi) or lithium diisopropylamide (LDA) in tetrahydrofuran (THF) to 1‐methoxy‐2‐aza‐allylanions, that can be alkylated, at C(3), exclusively, by various electrophiles (e.g.R‐X(X = I, Br), RCHO or methyl acrylate (see alsoScheme 6)). As the acidic hydrolyses (1NHCl) of benzimidates9and11leads to the corresponding α‐alkylated free amines15and18(Scheme 7and8), benzoyl derivatives16and19are obtained from the hydrolysis under basic conditions. On the other hand, it is observed that a catalyzedChapmanrearrangement of9and11results in the formation ofN‐benzoyl‐N‐methyl derivatives17and20(Scheme 7and8).The described reactions offer a simple me

ISSN:0018-019X    

DOI:10.1002/hlca.19810640509

出版商:WILEY‐VCH Verlag GmbH    

年代:1981

数据来源: WILEY

摘要:

Lithiation in α‐Position to the N‐Atom of Triphenylacetamides from Cyclic Secondary Amines. Rearrangements of Metalated Triphenylacetamides by 1,3‐Shift of Carbamoyl GroupsThe reagents2‐ generally available by lithiation of the triphenylacetamides1‐ react with non‐enolizable carbonyl compounds and benzyl halide (s.Tables 1and2, and products3). The limits of thermal stability of metalated triphenylacetamides above 0° are caused by a 1,3‐shift of the carbamoyl group into theo‐position of one of the benzene rings (s.2b→4and8a→10). The barriers to rotation around the amide bonds of four triphenylacetamides areca.16 kcal/

ISSN:0018-019X    

DOI:10.1002/hlca.19810640510

出版商:WILEY‐VCH Verlag GmbH    

年代:1981

数据来源: WILEY

摘要:

AbstractExperimental details are given for the previous preliminary reports concerning conversion of protoilludane (28) to hirsutene (3) and related reactions. Treatment of each of the bicyclic analogs9,10,12and13of the former compound afforded a hirsutene analog8, through multiple 1,2‐shift, together with other products. Treatment of a mixture of α‐ and β‐protoilludene ‐epoxides (29αand29β) with BF3· Et2O in hexane yielded hirsutane derivatives30and32. Compound30in turn was converted toendo‐hirsutene36, which had already been isomerized to

ISSN:0018-019X    

DOI:10.1002/hlca.19810640511

出版商:WILEY‐VCH Verlag GmbH    

年代:1981

数据来源: WILEY