Über Acylwanderungen an Phenolen

Rosenmund, Karl W.; Schnurr, W.

doi:10.1002/jlac.19284600105

Cited by 109 publications

(22 citation statements)

References 13 publications

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“…11-9 (2,930 g, Me: 6 % , 300 ml), fr. 11-10 (11,1), 79 (13,4), 77 (10,7), 69 (82,3), 53 (10,4), 41 (98,5), 27 (14,9), IR. , ont permis l'identification.…”

Section: Re'ggion 2;mentioning

confidence: 99%

“…(loo), 106 (59,3), 79 (20,7), 78 (13,9), 64 (4,4), 53 (32,7), 52 (47,8), 43 (12,6), 37 (7,4), 27 (16,O). (loo), 105 (97,5), 78 (16,1), 77 (98,8), 74 (7,0), 63 (2,3), 51 (39,2), 50 (20,4), 39 (6,7), 27 (3,9). (2,4), 137 (11,5) , 134 (3,3), 119 (5,5), 110 (21,1), 96 (17,3), 82 (26,7), 68 (69,2), 67 (loo), 55 (56,8), 43 (57,3), 27 (26.7).…”

Section: Re'ggion 2;unclassified

“…nature]), 2,5 (melange synth. )), 59 (86,1,98,7), 57 (44,6,47,6), 45 (100, loo), 43 (552, 63,3), 31 (78,3,87,8), 29 (452 34,6). IR.…”

Section: Re'ggion 2;mentioning

confidence: 99%

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Recherches sur les arǒmes 13^e communication [1] Sur 1′ arǒme de café. I

Stoll

Winter

Gautschi

et al. 1967

Helvetica Chimica Acta

189

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The analysis of a coffee concentrate is described: 202 constituents have been identified, 154 of which for the first time. Some of these compounds are new chemicals; their synthesis is described. Most identifications are based upon mass spectrometry combined in many cases with IR. spectrometry and comparison with reference compounds. MS. and IR. data are given in detail. The analysis shows that a large number of minor constituents is present, many of which could not be identified.

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“…11-9 (2,930 g, Me: 6 % , 300 ml), fr. 11-10 (11,1), 79 (13,4), 77 (10,7), 69 (82,3), 53 (10,4), 41 (98,5), 27 (14,9), IR. , ont permis l'identification.…”

Section: Re'ggion 2;mentioning

confidence: 99%

Section: Re'ggion 2;unclassified

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Recherches sur les arǒmes 13^e communication [1] Sur 1′ arǒme de café. I

Stoll

Winter

Gautschi

et al. 1967

Helvetica Chimica Acta

189

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“…Furthermore formation of the orrfto-substituted products, whichbecomes important at high temperatures in Solution, is largely predominant at low pressure in the gas-phase, i. e. under thermodynamically controlled conditions. In both cases a rationale for the thermodynamic stability of the orrAo-acetylated phenols is found in a relatively streng electrostatic interaction between the adjacent substituent groups [36][37][38].…”

Section: Comparison With Solution Chemistry Resultsmentioning

confidence: 99%

Gas-Phase Acylation Reactions. Acetylation of Phenols by Radiolytic CH₃CO⁺ Ions

Speranza¹,

Sparapani²

1981

Radiochimica Acta

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The gas-phase acetylation of repiesentative phenols by CH3CO''' ions from the 7-radiolysis of CH3F/CO mixtures has been investigated in the pressure ränge from 380 to 760 Ton, and in the presence of a gaseous base (NH3). At the higher system pressures, the competition between the n-type and the n-type nucleophilic Centers of the ambident substrates appears to be kinetically controUed and biased in favor of O-acetylation, as demonstrated by the predominant (from ca. 80 to ca. 97%) formation of aiyl acetates with respect to the isomeric hydroxy-acetophenones. The isomeric composition of the ring-acetylated products reflects the electrophilic character and the remarkable positional selectivity of the CH, CO"*" ion, which yields predominantly ortho-and para-hydroxy-acetophenones, in proportions depending on the total pressure and on the presence of NH,. In fact, oxygen-as well as orrAo-acetylated substrates, appear to be more stable than the other isomeric ionic intermediates, as indicated by their increased yields at the lowest total pressure used (380 Torr), under conditions of increased thermodynamic control of products. The results of competition experiments, carried out in the presence of mesitylene as the reference substrate, allow to determine a gas-phase acetylation reactivity scale from p-xylene to 2,6-xylenol, characterized by values ranging over three Orders of magnitude. Comparison of the gas-phase acetylation by CH, CO"'' ions with related reactions occurting in Solution reveals no basic mechanistic differences, the gas-phase reactivity and selectivity of free acetylium ions displaying significant analogies with those of acetylating reactants generated in low-polarity media by the action of poorly co-ordinating Friedel-Crafts catalysts on suitable precursors.

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“…Dans cette communication, nous decrivons la preparation et la transposition de quelques esters phenylacetiques, Les esters phenylacetiques utilises ont ete prepares par action du chlorure de phenylacetyle sur les phenols correspondants: phenylacetates de phenyle (1), F. 42°(de l'alcool) [8],p-tolyle (II), F. 75°(de l'alcool) [8], m-tolyle (III), F. 50°(de ['alcool) [9], o-tolyle (IV), F. 42°(de I'alcool) 3, 4, 5-trimethylphenyle (V) F. 47°( de I'alcool) et p-naphtyle (VI), F. 72°(de I'alcool).…”

unclassified