Ipso nitration. XX. Nitration of 5-tert-butyl-1,2,3-trimethylbenzene in acetic anhydride. Formation and rearomatization of adducts

Abstract

ALFRED FISCHER and KHAY CHUAN TEO. Can. J. Cheni. 56,1758Cheni. 56, (1978. Nitration of 5-/er/-butyl-l,2,3-trimethylbenzene in acetic anhydride gives both diastereomers of the adduct 1-/e~~/-butyl-3,4,5-trimethyI-4-nitrocycIohexa-2,5-dienyI acetate and one diastereonier of 1-/er/-butyl-3,4,5-trimethyl-4-nitrocyclohexa-2,5-dienol, in 91% yield, together with 5-/er/-butyl-l,2,3-trimethyl-4-nitrobenzene. Solvolysis of the dienyl acetate in acidified aqueous acetone and acidified methanol affords the diastereoniers of the dienols and the dienyl niethyl ethers, respectively. The dienyl methyl ethers are also formed from the dienyl acetate in neutral methanol and again o n reaction with methanolic sodium methoxide. The dienols isomerize (epimerize) in acidified aqueous acetone. Reaction of the dienyl niethyl ethers in aqueous methanol, o r prolonged reaction in methanol, results in t h e formation of methyl-1,2,3-triniethylphenyl ether. Similar cleavage of the ~~r~-b~~t y l group is the main reaction on solvolysis of the dienyl acetate in aqueous acetic acid. Under more acidic conditions the dienyl acetate gives 5-/er1-butyl-2,3-dimethyIbenzyl nitrite and lesser aniounts of 5-/er/-butyl-2,3-diniethylphenylnitromethane and 5-/er/-butyl-2,3-dimethylbenzyl acetate. In trifluoromethanesulfonic and fluorosulfonic acids 5-/er./-butyl-l,2,3-triniethyl-4-nitrobenzene is the major product.ALFRED FISCHER et KHAY CHUAN TEO. Can. J. Chem. 56, 1758Chem. 56, (1978. La nitration du /er/-butyl-5 trimethyl-1,2,3 benzene dans I'anhydride acetique conduit aux deux diastCrCoisomeres de I'adduit, acetate de /er/-butyl-l trimethyl-3,4.5 nitro-4 cyclohexaditne-2.5 yle. et B un diastereoisomere du ter.1-butyl-l trimethyl-3,4.5 nitro-4cyclohexaditne-2,5 ol avec un rendement de 91% aux c8tks du /er/-butyl-5 trimethyl-1,2,3 nitro-4 benzene. La solvolyse d e I'acetate de dienyle dans de I'acetone aqueuse acidulee et dans du methanol acidulk conduit respectivement aux diasterCoisonieres des dienols et des ethers niethyliques de dienyle. Les ethers methyliques de dienyle se fornient aussi a partir de I'acetate de ditnyle d a n s le methanol neutre et aussi par reaction du methylate de sodium en milieu niethanolique. Les dieriols s'isomerisent (epimerisent) en solution dans I'acetone aqueuse acidtilee. La reaction des Cthers niethyliques d e dienyle avec le nikthanol aqueux ou par action prolongee du niethanol conduit a la formation de I'Cther methylique du trimethyl-1,2,3 phtnyle. U n clivage semblablc d u groupe /cw-butyle correspond a la reaction principale observee lors de la solvolyse dc I'acktate de dienyle dans I.acide acetique aqueux. Utilisant des conditions plus acides, I'acttatc de dienyle conduit au nitrite du 1er1-butyl-5 dimethyl-2,3 benzyle et a des quantites plus faibles de /ert-butyl-5 dimethyl-2,3 phenylnitrolnethane et d'acetate du tcrt-butyl-5 dimethyl-2,3 benzyle. Dans les acides trifluoroniethanesulfonique et fluorosulfonique, le re,/-butyl-5 trimethyl-1,2,3 nitro-4 benzene est le produit principal.[Traduit par le journal]Ni...

ipso Nitration. XXIII. Reactions of cyclohexadiene adducts from nitration of 4-ethyltoluene in acetic anhydride

“…Thep-methylacetophenone was presumably formed from 1-(p-toly1)ethyl nitrite (cf. 3,12,13) or equivalent species such as the alcohol and nitrous acid. p-Ethyltoluene (10%) was also formed in this reaction and is likely to originate by loss of the nitronium ion from cation 4i.…”

Medium-Sized Cyclophanes. 43.1 First Evidence for anti−syn-Ring Inversion under the Nitration of 5,13-Di-tert-butyl-8,16-dimethoxy[2.2]metacyclophane

“…Although the replacement of a tert -butyl group by a nitro group in electrophilic aromatic substitutions has frequently been described in the literature, , generally the yields are modest because of the accompanying side reactions . Only in activated compounds are better yields obtained.…”

ipso-Acylation of 5,13-di-tert-butyl-8,16-dimethyl[2.2]metacyclophane with acid anhydrides: Through-Space Electronic Interaction among the Two Benzene Rings

“…Although the replacement of a tert-butyl group by a nitro group in electrophilic aromatic substitutions has frequently been described, [9][10][11][12][13][14][15][16] generally the yields are modest because of the accompanying side reactions. 17 Only in activated compounds are better yields obtained.…”