ipso-Nitration: formation of nitronium acetate adducts in the nitration of p-acetamido-, p-halogeno-, and p-methoxy-toluenes, and α-p-tolyloxyisobutyric acid

Fischer, Alfred; Fyles, Deborah L.; Henderson, George N.

doi:10.1039/c39800000513

Cited by 5 publications

(7 citation statements)

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“…Figure 4 shows that in 63.0% H2S04 (1) is about equally partitioned between capture and 1,2-rearrangement, so the extent of @soattack at C-Me in the nitration of 4-chlorotoluene is indicated to be roughly 50%. This value is considerably larger than the minimum value of 27% suggested earlier [see (3)],* and more comparable to the result of Fischer et al for nitration in acetic anhydride, mentioned at the beginning of this paper.…”

Section: Discussionsupporting

confidence: 84%

“…The yields of the chloronitrotoluenes fall off at low acidities because of nucleophilic capture by water of the Wl's, (1) and (2). Because it could not be assumed that at the lowest acidity studied (63% H2S04) capture was complete, and because nitrodechlorination did not occur, the results allowed positional reactivities to be evaluated only in the form represented in (3).…”

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confidence: 99%

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Electrophilic aromatic substitution. Part 30. The kinetics and products of the solvolyses in aqueous sulphuric acids of 5-chloro-2-methyl-2-nitrocyclohexa-3,5-dienyl acetate: the occurrence of A AC2 and A AL 1 solvolyses, and of an acid-catalysed elimination of nitrous acid, and the relationship of the A AL 1 solvolysis to the nitration of 4-chlorotoluene

Bloomfield¹,

Moodie²,

Schofield³

1983

J. Chem. Soc., Perkin Trans. 2

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Good first-order kinetics of solvolysis of the above-named diene in water and in 6.5-43.6% H2S04 at 25 "C, and in water and in 15.2-58.8% H,SO, at 5 "C have been observed. The yields of 4-chlorotoluene, 5-chloro-2-methylphenyl acetate, 5-chloro-2-methylphenol, 4-chloro-2-nitrotoluene, 4chloro-3-nitrotoluene, and 4-methyl-2-nitrophenol produced in water and in 21.5-92.4% H2S04 at 25 "C in the presence of sulphanilic acid or hydrazinium sulphate, and additionally of 2and 4-nitroanisole when anisole was also added, have been measured. The solvolysis proceeds by an acid-catalysed elimination of nitrous acid (confirming a tentative conclusion in another case I ) , which competes with A,,2 and AAL1 ester solvolyses. With increasing acidity the solvolyses become dominant, the AALl reaction increasingly so. The small yield of 4-chloro-3-nitrotoluene comes from a thermal reaction of the diene unrelated to the elimination and solvolyses. The AAL1 reaction generates the ipso-Wheland intermediate (WiMe) that is also formed in the nitration of 4-chlorotoluene. The intermediate reacts by return to 4-chlorotoluene and nitronium ion (which can be captured by anisole), by 1,2-and 1,4-nucleophi lic capture by water (giving 5 -c h loro -2-met hylphenol and 4-methyl -2-nitrop henol, respectively), and by 1,2-rearrangement to 4-chloro-2-nitrotoluene. The first of these reactions never accounts for more than about 12% of the WiMe and competition between capture and rearrangement moves strongly in favour of the latter with increasing acidity. Re-examination of the nitration of 4-chlorotoluene has revealed products

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Section: Discussionsupporting

confidence: 84%

mentioning

confidence: 99%

Electrophilic aromatic substitution. Part 30. The kinetics and products of the solvolyses in aqueous sulphuric acids of 5-chloro-2-methyl-2-nitrocyclohexa-3,5-dienyl acetate: the occurrence of A AC2 and A AL 1 solvolyses, and of an acid-catalysed elimination of nitrous acid, and the relationship of the A AL 1 solvolysis to the nitration of 4-chlorotoluene

Bloomfield¹,

Moodie²,

Schofield³

1983

J. Chem. Soc., Perkin Trans. 2

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“…115.4 and 114.5 (C-2, C-3, C-5, and C-6), 69.7 (OCH2CD2), 60.6 (quintet, OCH2CD2OH, JC-d = 22 Hz), 55.6 (OCH3) ppm; MS (70 eV) 170 (43, M+), 125 (14), 124 (100), 110 (19), 109 (84), 95 (10), 81 (17), 77 (12), 63 (12), 53 (10).…”

Section: Methodsmentioning

confidence: 99%

Aromatic nitration with ion radical pairs [ArH.cntdot.+,NO2.cntdot.] as reactive intermediates. Time-resolved studies of charge-transfer activation of dialkoxybenzenes

Sankararaman¹,

Haney²,

Kochi

1987

J. Am. Chem. Soc.

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“…Completely dried LTA in a plastic tube with a screw-cap was dissolved in 0.1 ml of cold 48% HF and kept at 4°C for 48-65 h. HF was evaporated under vacuum at 4°C over NaOH. The residue was transferred to a glass tube by successive washings with 0.75 ml of 10 mM acetic acid, 1 ml CH3OH and 0.75 ml of 10 mM acetic acid [14]. Two ml CHC13 were then added to yield two layers.…”

Section: Hydrogen Fluoride Treatment Of Ltamentioning

confidence: 99%

“…Hydrogen fluoride under the proper conditions will degrade phosphodiester and phosphomonoester bonds in molecules without destroying most acyl ester and glycosidic bonds [1,13,14]. Since the LTA of S. faecium is a polymer of glycerol phosphate units linked through 1,3-phosphodiester bonds, HF should breakdown the polymer to glycerol and glycerol substituted with carbohydrate.…”

Section: Products Derived From Hf Treatment Of [14cglycerol] L Tamentioning

confidence: 99%

Evidence for a tetraglucoside substituent on the lipoteichoic acid of Streptococcus faecium ATCC9790

Cabacungan

1985

FEMS Microbiology Letters

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Hydrogen fluoride treatment of [14Cglycerol]lipoteichoic acid synthesized by growing Streptococcus faecium ATCC9790 in the presence of 1,3[14C]glycerol produced five radioactive, water-soluble products which were identified by chromatographic and analytical techniques to be tetraglucosyl glycerol, triglucosyl glycerol, diglucosyl glycerol, monoglucosyl glycerol and unsubstituted glycerol. The percent composition of each varied modestly from culture to culture and ranged between 7 and 8% for the tetra-, 20.5 and 31.2% for the tri-, 11.3 to 23.5% for the di-, 20.9 to 26.8% for the mono-, and 23.1 to 34.8% for the unsubstituted glycerol. The same glucosylated glycerol compounds could be obtained in an in vitro reaction in which a 30000 × g particulate enzyme catalyzed the incorporation of [3H]glucose from UDP [3H]glucose into lipoteichoic acid.. acylglycerol or kojibiosyl diacylglycerol bonded at one end [1-3]. The glycerol phosphate chain is substituted to various extents at the free hydroxyl of carbon 2 of the glycerol units with carbohydrate. The carbohydrate in group D streptococci is usually a kojibiose or kojitriose (~x-1 ~ 2 linked D-glucose di-or trisaccharide) which may bear o-alanine ester residues [4][5][6]. The possibility of a monoglucosyl substituent on the LTA of S. faecium has also been alluded to [7]. While studying the biosynthesis of the LTA of S. faecium with [14C]glycerol, we detected a radioactive compound on chromatograms that had the properties expected of a tetrasaccharide substituent of the LTA. In this report we demonstrate the in vivo and in vitro synthesis of this tetraglucoside as well as the other saccharide substituents of the LTA of S. faecium.

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ipso-Nitration: formation of nitronium acetate adducts in the nitration of p-acetamido-, p-halogeno-, and p-methoxy-toluenes, and α-p-tolyloxyisobutyric acid

Cited by 5 publications

References 0 publications

Aromatic nitration with ion radical pairs [ArH.cntdot.+,NO2.cntdot.] as reactive intermediates. Time-resolved studies of charge-transfer activation of dialkoxybenzenes

Evidence for a tetraglucoside substituent on the lipoteichoic acid of Streptococcus faecium ATCC9790

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