- Condensations of 1,4-Cyclohexanediones and Secondary Aromatic Amines. The Formation of Alkyldiarylamines and Triarylamines
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Condensation of 1,4-cyclohexanedione with N-alkylarylamines gives N-alkyl-N-arylanilines, and that with diarylamines gives triarylamines.A mechanism involving dehydration of monoenamines of the 1,4-dione is proposed for the reaction.Relative rates of substituted N-ethylanilines on competitive reactions plotted vs.Hammet's ? values gave -2.0 as the ρ value.In separate reactions, however, a different tendency is noted for the yield, that is, the ease of reactions with p-chloro and p-nitro derivatives.This discrepancy is explained in terms of acidities of the conjugate acids of the amines used as the actual catalysts.
- Haga, Kazuo,Oohashi, Masayuki,Kaneko, Ryohei
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p. 1586 - 1590
(2007/10/02)
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- 1,2-Disubstituted Ethanes As Possible Precursors For The Synthesis of Cannabis Spirans
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Three possible methods for converting suitable 1,2-disubstituted ethanes into Cannabis spirans have been investigated. 4',5-Dihydroxy-3-methoxybibenzyl underwent intramolecular o-p- and p-p-coupling with ferricyanide in a chloroform-aqueous potassium carbonate system, but yields were low: certain other oxidants did not succeed or gave only traces of product.A method for making 1-hydroxy-1-(3,5-dimethoxyphenylethyl)cyclohexan-4-one ethylene acetal or thioacetal via a Birch reaction is described: despite favourable precedent, acid-catalysed cyclisation led to octahydrophenanthrenones rather than spiro-ketones, whilst N,N-dimethylformamide dineopentyl acetal gave two olefins.Jacquesy's super-asid method for making spirocyclohexenones from a methoxylated bibenzyl was not applicable to the 3,4',5-trimethoxy-case, which would have given cannabispirenone methyl ether, presumably because of protonation of both aromatic systems.
- Crombie, Leslie,Crombie, W. Mary L.,Jamieson, Sally V.,Tuchinda Patoomratana,Whitaker, Alison J.
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p. 1485 - 1492
(2007/10/02)
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