摘要:

AbstractProtons are subject to the wave/particle dualism of matter. Hitherto, only the copruscular picture has been generally used in chemistry for describing protons. In contrast, the wave picture is considered in the present article. Protonic states, proton delocalization, and the tunnel effect in chemistry are discussed and illustrated by examples.

ISSN:0570-0833    

DOI:10.1002/anie.196401571

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe chemistry of aromatic compounds was originally confined to benzenoid hydrocarbons and their derivatives but has been enriched in the last decade by the discovery of numerous non‐benzenoid, cyclically conjugated systems that are more or less like benzene in their properties. This has necessitated a new conception of “aromatic character”. Theoretical and experimental studies have been applied to this problem. In this connection, several selected representatives of this class of compound are described, mostly from studies by the author's own group, and relationships between structure and “aromatic character” are

ISSN:0570-0833    

DOI:10.1002/anie.196401651

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractTrialkylboranes with identical or different groups on the boron are stable to alkyl exchange at room temperature. Mixed trialkylboranes only undergo disproportionation in the presence of catalysts such as aluminum trialkyls and boron‐hydrogen compounds. At temperatures above 100 °C, organoboranes such as trialkylboranes and B‐alkylboracyclanes isomerize as a result of migration of the boron along the aliphatic hydrocarbon radical via dehydroboration‐hydroboration equilibria. Alkyl, cycloalkyl, as well as aralkyl and certain arylboranes can be converted irreversibly by pyrolysis at 200–300 °C into other organoboranes (methylboranes and boron‐heterocycles of various

ISSN:0570-0833    

DOI:10.1002/anie.196401741

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe relationship between the structure and the catalytic activity of nickel(II) complexes in the synthesis of cyclooctatetraene by the method of W. Reppe is discussed. The cyclotetramerization of acetylene takes place within labile Ni(II)‐acetylene π‐complexes. Inhibition tests have made it probable that four molecules of acetylene are grouped around the nickel ion in the transition state, in a configuration which favors the formation of the eight‐membere

ISSN:0570-0833    

DOI:10.1002/anie.196401851

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractProvided they contain quaternary nitrogen, simple phenolic bases can undergo oxidative condensation under conditions similar to those of biogenesis to form alkaloids of the isoquinoline series with good yields. By means of such oxidative condensations, more than sixty alkaloids of various structural types have become more easily obtainable. Of the numerous possible condensations of the intermediate mesomeric radicals only those which lead to naturally occurring alkaloids give good yields and few by‐products. The results suggest that oxidative condensations of quaternary bases are also involved in the biosynthesis of alkaloids in the plant cel

ISSN:0570-0833    

DOI:10.1002/anie.196401921

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196402001

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractCondensation of nitromethane with suitable diadehydes in alkaline medium provides a general method of cyclization, in which the methyl group of the nitromethane is incorporated into the ring. This method leads to 5‐, 6‐, and 7‐membered rings and is equally applicable to aliphatic, aromatic, and sugar dialdehydes. For example, glyoxal is converted into 1,4‐dideoxy‐1,4‐dinitro‐neo‐inositol, and glutaraldehyde into trans‐2‐nitrocyclohexane‐1,3‐diol, while the corresponding cyclization of xylo‐trihydroxyglutaraldehyde leads to deoxy‐nitroinositols having the scyllo, myo‐1, and muco‐3 configurations.‐In the case of aromatic dialdehydes, the cyclization is accompanied by elimination of water. Thus, phthalaldehyde, naphthalene‐2,3‐dicarboxaldehyde, and homophthalaldehyde yield, respectively, 2‐nitroindenol, 2‐nitrobenzindenol, and 2‐nitronaphthalene. ‐Application of the method to sugar dialdehydes (aldehydic diglycol derivatives of monosaccharides formed by periodate oxidation) constitutes an excellent synthesis of 3‐amino sugars, since 3‐deoxy‐3‐nitropyranoses are formed smoothly on cyclization, and the corresponding 3‐amino derivatives are obtained by hydrogenation. Thus, the reaction sequence: periodate oxidation → cyclization with nitromethane → hydrogenation, leads in the case of α‐and β‐D‐pentosides to 3‐amino‐3‐deoxy‐D‐and‐L‐pentosides, respectively, with ribo, xylo, and arabino configurations. α‐D‐hexosides give derivatives with gluco, manno, and galacto configurations. 3‐Amino‐3,6‐dideoxyglucosides of theD‐andL‐series are obtained from 6‐deoxy‐D‐or‐L‐hexosides, respectively, and 3‐aminohexosans with gulo, ido, and altro configurations are obtained from 1,6‐anhydro sugars. Cyclization of the dialdehydes obtained from sedoheptulose and methyl 4,6‐O‐ethylidene‐α‐D‐glu

ISSN:0570-0833    

DOI:10.1002/anie.196402111

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196402241

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196402252

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196402262

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY