摘要:

AbstractThe tosylhydrazones of 4‐allyl‐ and 4‐crotyl‐4‐methyl‐cyclohexa‐2, 5‐dien‐l‐one (14and15) rearrange in the presence of acid to yield the corresponding 2‐allyl‐ and 2‐α‐methylallyl‐hydrazines17and18, respectively. A similar behaviour is shown by the tosylhydrazone of 2‐allyl‐2‐methyl‐cyclohexa‐3, 5‐dien‐1‐one (16).16could not be isolated. The observed acidcatalysed [3 s, 3 s]‐sigmatropic rearrangement of the tosylhydrazones can be regarde

ISSN:0018-019X    

DOI:10.1002/hlca.19710540402

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe synthesis of the protected octapeptide N‐t‐butoxycarbonyl‐phenylalanyl‐valylasparaginyl‐glutaminyl‐Nim‐tritylhistidyl‐leucyl‐S‐benzhydrylcysteinyl‐glycine‐hydrazideL, corresponding to the amino‐terminal sequence of the insulin B‐chain, is described. Up to the protected octapeptide all intermediates have greatly improved solubility properties in neutral organic solvents in comparison with other synthetic deriv

ISSN:0018-019X    

DOI:10.1002/hlca.19710540403

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

Abstract2‐Acetyl‐1, 4‐benzochinon und 2‐Methoxycarbonyl‐1, 4‐benzochinon setzen sich unter sehr milden Bedingungen mit Enolen (Acetessigester, Cyclohexan‐1, 2‐ und Cyclohexan1, 3‐dione) unter C‐C‐Verknüpfung um. Die entstandenen Hydrochinone wurden in substituierte Benzofuran‐3‐carbonsäureester und Cumaran‐2‐one umgewandelt. Oxydation von 2‐Methyl‐3‐acetyl‐4‐hydroxy‐benzofuran‐3‐carbonsäure‐äthylester führte zum 2‐

ISSN:0018-019X    

DOI:10.1002/hlca.19710540404

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

Abstract2‐Acetyl‐1,4‐benzochinon, das ein stärkeres Elektrophil als Benzochinon ist, setzt sich unter sehr milden Bedingungen mit Enoläthern zu 2‐Alkoxy‐4‐acetyl‐5‐hydroxy‐2,3‐dihydrobenzofuranen, mit Acetylenäthern zu den entsprechenden Benzofuranen, mit 3,4‐Dihydrofuran zu hydrierten Furo[2, 3‐b]‐furanen und mit 5, 6‐Dihydropyran zu hydrierten Pyrano[2, 3‐b]‐furanen um. Unter gewissen Bedingungen führt die Kondensation zwischen Acetylbenzochinon und Furan oder Silvan zum hydrierten Furo[3, 2‐b]furan‐System. Imidazol und 2, 5‐Dimethylprazol addieren mit dem N; Pyrrole werden in α‐oder β‐Stellung mono‐ oder disubstituiert zu violetten oder blauen Pyrrolchinonen. Arbeiten früherer Autoren über Add

ISSN:0018-019X    

DOI:10.1002/hlca.19710540405

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractAcetylbenzochinon und Methoxycarbonylbenzochinon lassen sich in säurekatalysierter Reaktion und unter milden Bedingungen mit Phenolen, Phenoläthern, Dimethylanilin, Alkylbenzolen, Methoxybenzoesäureestern und Hydroxybenzoesäureestern zu Biphenylhydrochinonen und ‐chinonen kondensieren, deren Strukturen durch Spektren und, wenn nötig, durch oxydativen Abbau gesichert wurden. Die Substitutionsorte entsprechen weitgehend denjenigen einerFriedel‐Crafts'schen Acylierungs

ISSN:0018-019X    

DOI:10.1002/hlca.19710540406

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe valence vibrations CH and CD of a number of alkanes and of (CH3)3CX are studied using compounds deuterated in specific positions. For the methyl and the methylene groups an experimental model of group frequencies is proposed, which allows some general conclusions to be drawn concerning the assignation of the frequencies. The methyl group always shows aFermiresonance between νsand 2δasin the region of 2930–2870 cm−1. In consequence the unperturbed νsCH3frequency may be situated at ∽2915 cm−1and the absence of a coupling with other groups can be checked. The vibrations of the methylene group adjacent to a methyl group have higher frequencies than those of CH2groups further removed. The coupling of the methylene group with other groups is always strong and may amount to 10 cm−1. For a chain of methylene groups, the coupling is the larger the longer the chain; being relatively small for symmetrical modes (∽3 cm−1) for the antisymmetric mode. A correlation is found between protonated and deuterated groups which leads to isotope effects comparing well

ISSN:0018-019X    

DOI:10.1002/hlca.19710540407

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractThe fundamentals and overtones of the CH stretching vibrations of a number of halogenated methanes and deuteriomethanes are compared with a hypothetical model consisting of isolated groups. The anharmonicity constants are evaluated and lie between −20 cm−1and −130 cm−1for the CH and CD stretching vibrations. The value of the anharmonicity constant for a coupling between two different modes of vibration is always greater (in absolute numbers) than its value for an overtone of one frequency. The constant is larger for a symmetric mode than for an asymmetric mode in the case of a CH vibration; the contrary is true for a CD bond. Complex interactions between different vibrations often strongly modify the spectra of the overtones. It is shown, however, that the conception of an isolated group is helpful for evaluating the spectra of

ISSN:0018-019X    

DOI:10.1002/hlca.19710540408

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractAnalysis of the photoelectron spectrum of homofulvene (1) (spiro [2.4] hepta‐4,6‐diene) confirms the conclusions previously drawn concerning the direct conjugation between π‐andWalsh‐orbitals. It is shown that the resonance integral (4) appropriate for the semi‐quantitative interaction of these orbitals amounts to −1.9 eV, i.e. nearly the value for conjugating π‐orbitals (β = −2.4 to −2.5 eV). This explains the close analogy between the photoelectron spectrum of

ISSN:0018-019X    

DOI:10.1002/hlca.19710540409

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractFulvenes are prepared by condensation of sodium cyclopentadienide with x‐acetoxy‐x‐chloro‐hydrocarbon derivatives, followed by elimination of acetic acid with triethylamine. The yields are approximately 60% for 6‐alkylfulvenes and similar to those of the classical synthesis for 6, 6‐polymethylenefulvenes. The reaction is carried out at low temperatures and under water‐free conditions. The purification of the fulve

ISSN:0018-019X    

DOI:10.1002/hlca.19710540410

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY

摘要:

AbstractESR. spectra are reported for the radical anions of the diketones I and II (see below), recently prepared from 1, 6‐methano[10]annulene and its 11, 11‐difluoro‐derivative, respectively [1]. The π‐spin populations of I⊖ and II⊖ are shown to be incompatible with the structure A an enedione‐norcaradiene. Although the alternative structure B of a [10]annulenequinone is acceptable for both I⊖ and II⊖, the ESR. data is more satisfactorily rationalized in terms of a structure ‘intermediate’ to A and B. This is particularly true for the radical anion I⊖, for which the π‐spin populations suggest a structural ‘shift’ B → A relative to II⊖. Structures A and B were postulated [1]for the neutr

ISSN:0018-019X    

DOI:10.1002/hlca.19710540411

出版商:WILEY‐VCH Verlag GmbH    

年代:1971

数据来源: WILEY