An Addition Reaction of Indane with Nitric Acid in Acetic Anhydride

Fischer, A.; Greig, C. C.; Leonard, D. R. A.

doi:10.1139/v72-355

Cited by 8 publications

(4 citation statements)

References 13 publications

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“…Striking examples arise from nitrations with solutions prepared from nitric acid and acetic anhydride, reagents for which there is still doubt about the identity of the electrophile.7 All involve intermediates of the type W;R, where R is methyl or some related hydrocarbon side chain. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Examples are the stereoisomers la and lb from o-xylene.8,9 The position which captures acetate can also be substituted, as in the adducts from p-xylene9,20 and 3,4-dimethylanisole.15 li JJi Other nucleophiles such as the nitrate ion can capture Wi's. 13 Acidolysis of nitroacetates of the kind mentioned regenerates the W; which can attack reactive aromatics; loss of nitrous acid then gives biaryls.17,21…”

Section: Consequences Of Ipso Attackmentioning

confidence: 99%

Ipso attack in aromatic nitration

Moodie¹,

Schofield²

1976

Acc. Chem. Res.

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Aromatic Nitration 287ate), the necessary internal return results in insignificant oxygen ~c r a m b l i n g .~~ If ion pairs formed under solvolytic conditions undergo rearrangement, attack by an added nucleophile, although rate limiting, must always suppress rearrangement20~38kv3Q since no example of skeletal rearrangement accompanying second-order substitution has ever been reported, even for the potentially favorable neopentyl case.75 These ion pairs must be "more intimate than intiand must thus behave like polarized RX molecules. This is what we believe they are, but we see no reason to call them ion pairs, for in such terms a methyl iodide molecule could be regarded as an ion pair by virtue of the C-I bond polarity.43 This would be fine in the present context since mechanistic distinction would be lost, but chemical problems cannot be solved by such semantic extensions, although we agree with the view that genuine ion pairs may possess a degree of covalent character. In fact, the postulation of ion-pair intermediates (and their formation with solvent assistance) in simple primary and secondary substrate solvolysis in reasonably nucleophilic solvents may be incorrect, and sN2 solvent attack may be the favored mode. We know of no evidence that demands intermediates in such simple solvolyses, and specifically intermediates formed without solvent or neighboring group assistance. If so, (74) A. F. Diaz, I. Lazdins, and S. Winstein, J. Am. Chern. Soc., 90, 1904 (1968). If such scrambling were detected it would still be difficult to prove that it did not occur in a mechanistic blind alley (see also ref 5). (75) Reference 1, p 742. See also G. M. Fraser and H. M. R. Hoffmann, Chem Cornrnun, 561 (1967). (76) Reference 7, p 366.there is no reason why they should intervene in nonsolvolytic substitutions with stronger nucleophiles.In summary, the "extra-intimate ion pair" is in our opinion a polarized RX molecule. The polarization arises from approach of N-, and the energy buildup needed to cross the sN2 potential barrier arises largely from solvent re~rganization~~ attendant on the merging of the original Nand RX solvation shells. We deliberately choose these words to mimic Bordwell's description of an ion-sandwich intermediate,26 noting that Bordwell himself has not been definite in postulating actual intermediacy. His results could equally well be rationalized in terms of a loose sN2 transition state (4) for his tertiary substrate and a tighter transition state (3) for the model primary system.In conclusion, the verdict which must be passed on Sneen's proposed universal unification of s N 1 and SN2 mechanisms is one which is unique to the Scottish legal system, and so I turn to the words of my forbears in stating "not proven". A more positive conclusion is not presently available, but we note that strides in this direction are being made through heavy atom isotope effect studies.45 I warmly thank Professors P. B. D. de la Mare, J. M. Harris, P. v. R. Schleyer, J. Seyden-Penne, R. A . Sneen, and J. Warkentin for ex...

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Section: Consequences Of Ipso Attackmentioning

confidence: 99%

Ipso attack in aromatic nitration

Moodie¹,

Schofield²

1976

Acc. Chem. Res.

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“…spectrum indicated that approximately 70% of dienes had been formed. The mixture was worked up in the normal manner (10) to yield an oil consisting of (by n.m.r.) 68% dienes, 20% 3,4-dimethyl-6-nitroacetophenone, and lesser amounts of 3,4-dimethyl-2-nitroacetophenone and 3,4-dimethyl-5-nitroacetophenone.…”

Section: Nitration Oj'33-dimethylacetophenonementioning

confidence: 99%

Nitration of 3,4-Dimethylacetophenone and 3,4-Dimethylbenzophenone. Formation and Rearomatization of Adducts

Fischer¹,

Greig²,

Röderer³

1975

Can. J. Chem.

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Nitration of 3,4-dimethylacetophenone in acetic anhydride gives a mixture of cis-and trans-2-acetyl-4,5-dimethyl-4-nitro-1,4-dihydrophenyl acetate as the main product, together with 3,4-dimethyl-2-, 3,4-dimethyl-5-, and 3,4-dimethyl-6-nitroacetophenone. Analogous products are obtained from 3,4-dimethylbenzophenone. Rearomatization of the adducts under mildly acidic conditions occurs via 1,4-elimination of nitrous acid to form 2-acetyl- and 2-benzoyl-4,5-dimethylphenyl acetate, respectively. In strongly acidic conditions elimination of acetic acid accompanied by 1,2- and 1,3-shifts of the nitro group occurs to form the 2- and 5-nitro derivatives of the parent ketones. The rearomatization to the nitro derivatives involves the intermediate formation of an ipso-cyclohexadienyl cation which may be trapped by anisole or mesitylene to form biphenyl derivatives.

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“…Although several analytical techniques were used for the identification of 4-NI [42,48,49], the first analytical methods (polarographic and voltammetric) for its determination have been reported at mercury electrodes in 2016 [50]. The cathodic determination of 4-NI has been carried out using direct current tast polarography (with the limit of quantification (L Q ) of 0.65 μmol L À 1 ) and differential pulse polarography (L Q of 0.10 μmol L À 1 ) at a classical dropping mercury electrode and using direct current voltammetry (DCV) (L Q of 0.075 μmol L À 1 ) and differential pulse voltammetry (DPV) (L Q of 0.070 μmol L À 1 ) at a hanging mercury drop minielectrode [50].…”

Section: Introductionmentioning

confidence: 99%