Nitration of 4-tert-butyl-o-xylene in acetic anhydride. Formation and rearomatization of adducts

Nitration of 4-tert-butyl-1,2-dimethylbenzene in acetic anhydride gives trans-1-tert-butyl-3,4-dimethyl-4-nitro-1,4-dihydrophenyl acetate (6), trans-1-tert-butyl-3,4-dimethyl-4-nitro-1,4-dihydrophenol, 2-tert-butyl-4,5-dimethylphenyl acetate, 5-tert-butyl-2-methylbenzaldehyde, 4-tert-buty]-1,2-dimethyl-5-nitrobenzene, and 4-tert-butyl-1,2-dimethyl-6-nitrobenzene. 2-tert-Butyl-4,5-dimethylphenyl acetate and 3,4-dimethylphenyl acetate are the major products of solvolysis of 6 in moist acetic acid. Both of these compounds are likely formed via the cation generated by ionization of the nitro group. Under more acidic conditions 5-tert-butyl-2-methylbenzaldehyde and 4-tert-butyl-1,2-dimethyl-6-nitrobenzene, formed via the cation generated by acid-catalysed loss of acetate, become dominant, the balance between these products being controlled by the basicity of the solvent. More basic solvents deprotonate the cation to a triene, a key step in the formation of the aldehyde, at a competitive rate with the nitro group migration.

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

Canadian Journal of Chemistry ◽

10.1139/v75-222 ◽

1975 ◽

Vol 53 (11) ◽

pp. 1570-1578 ◽

Cited By ~ 7

Author(s):

Alfred Fischer ◽

Colin Campbell Greig ◽

Rolf Röderer

Keyword(s):

Acetic Acid ◽

Acetic Anhydride ◽

Nitro Group ◽

Nitrous Acid ◽

Main Product ◽

Intermediate Formation ◽

Nitro Derivatives ◽

Acidic Conditions ◽

Cis And Trans ◽

Derivatives Of

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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Formation of Adducts in the Nitration of 2,3- and 3,4-Dimethylbenzonitriles, and their Rearomatization. A 1,3-Nitro Shift

Canadian Journal of Chemistry ◽

10.1139/v74-192 ◽

1974 ◽

Vol 52 (8) ◽

pp. 1231-1240 ◽

Cited By ~ 3

Author(s):

Alfred Fischer ◽

Colin Campbell Greig

Keyword(s):

Acetic Acid ◽

Acetic Anhydride ◽

Nitro Group ◽

Nitrous Acid ◽

Nitro Derivative ◽

Acidic Conditions

Nitration of 2,3-dimethylbenzonitrile in acetic anhydride gives the adduct 2-cyano-3,4-dimethyl-4-nitro-1,4-dihydrophenyl acetate as well as the expected nitro substitution products. Similarly 3,4-dimethylbenzonitrile affords 2-cyano-4,5-dimethyl-4-nitro-1,4-dihydrophenyl acetate as well as the 3,4-dimethylnitrobenzonitriles. Thermolysis or decomposition in acetic acid of the adducts gives the original dimethylbenzonitrile and its 5-nitro derivative as the major products, the latter apparently being formed by an intramolecular 1,3-shift of the nitro group. Decomposition of the adducts under more strongly acidic conditions results in the elimination of nitrous acid and the formation of 2-cyano-3,4-dimethylphenyl acetate and 2-cyano-4,5-dimethylphenyl acetate, respectively. In acidified methanol the adducts undergo transesterification at the acetate function and 2-cyano-3,4-dimethyl-4-nitro-1,4-dihydrophenol and 2-cyano-4,5-dimethyl-4-nitro-1,4-dihydrophenol are obtained.

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The bromination and chlorination of 2,3-dialkylindoles. Isolation of 3-bromo- and 3-chloro-2,3-dialkylindolenines and acid catalyzed conversion to 3-methoxyindolenines

Canadian Journal of Chemistry ◽

10.1139/v80-126 ◽

1980 ◽

Vol 58 (8) ◽

pp. 808-814 ◽

Cited By ~ 14

Author(s):

Gary I. Dmitrienko ◽

Edward A. Gross ◽

Susan F. Vice

Keyword(s):

Acetic Acid ◽

Good Yield ◽

Room Temperature ◽

Chemical Properties ◽

Nitrogen Atmosphere ◽

Crystalline Solid ◽

Tert Butyl ◽

Acidic Conditions ◽

Acid Catalyzed

The bromination of 2,3-dimethylindole in acetic acid followed by hydrolysis has been shown to yield the known dimer 16 of 3-hydroxy-2,3-dimethylindolenine 15 and not 3-hydroxymethyl-2-methylindole 12 as reported previously by others. Bromination of 2,3-dimethylindole in the presence of triethylamine has yielded 3-bromo-2,3-dimethylindolenine 17 as a crystalline solid which is stable at room temperature in a nitrogen atmosphere in the presence of triethylamine but decomposes vigorously in the absence of base. Under mildly acidic conditions 17 reacts rapidly with methanol to yield 3-methoxy-2,3-dimethylindolenine 3 in good yield. With tert-butyl hypochlorite in the presence of triethylamine, 2,3-dimethylindole gives 3-chloro-2,3-dimethylindolenine 2 which has chemical properties similar to 17 reacting readily with methanol to give 3. Similarly tetrahydrocarbazole was converted to the analogous chloroindolenine 5 and bromoindolenine 18 both of which readily underwent methanolysis to give 6 in good yield. A mechanism for the acid catalyzed methanolysis of 3-chloro- and 3-bromoindolenines is proposed.

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Nitration of p-tert-butyltoluene in acetic anhydride. 1,2 and 1,4 adducts

Canadian Journal of Chemistry ◽

10.1139/v76-568 ◽

1976 ◽

Vol 54 (24) ◽

pp. 3978-3985 ◽

Cited By ~ 6

Author(s):

Alfred Fischer ◽

Rolf Röderer

Keyword(s):

Acetic Anhydride ◽

Hydrogen Chloride ◽

Nitrous Acid ◽

Tert Butyl ◽

Acidic Conditions ◽

Cis And Trans

Nitration of p-tert-butyltoluene in acetic anhydride gives 5-tert-butyl-2-methyl-2-nitro-1,2-dihydrophenyl acetate (43%), cis- and trans-1-tert-butyl-4-methyl-4-nitro-1,4-dihydrophenyl acetate (16%) and 4-tert-butyl-2-nitrotoluene (41%). Reaction of either of the 1,2 or 1,4 nitroacetoxy adducts with hydrogen chloride gives a mixture of the 1,2 and 1,4 nitrochloro adducts. The 1,2 (secondary) acetate adduct eliminates nitrous acid to form 5-tert-butyl-2-methylphenyl acetate under mildly acidic conditions. Under more vigorously acidic conditions 4-tert-butyl-2-nitrotoluene is formed. The same products are formed from the 1,4 (tertiary) acetate adducts but p-tolyl acetate is also obtained. The 1,2 and 1,4 adducts couple with anisole to form 5-tert-butyl-4′-methoxy-2-methylbiphenyl.

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

Canadian Journal of Chemistry ◽

10.1139/v78-285 ◽

1978 ◽

Vol 56 (13) ◽

pp. 1758-1768 ◽

Cited By ~ 3

Author(s):

Alfred Fischer ◽

Khay Chuan Teo

Keyword(s):

Acetic Anhydride ◽

Major Product ◽

Aqueous Acetone ◽

Main Reaction ◽

Aqueous Acetic Acid ◽

Aqueous Methanol ◽

Tert Butyl ◽

Butyl Group ◽

Tert Butyl Group ◽

Acidic Conditions

Nitration of 5-tert-butyl-1,2,3-trimethylbenzene in acetic anhydride gives both diastereomers of the adduct 1-tert-butyl-3,4,5-trimethyl-4-nitrocyclohexa-2,5-dienyl acetate and one diastereomer of 1-tert-buty]-3,4,5-trimethyl-4-nitrocyclohexa-2,5-dienol, in 91% yield, together with 5-tert-butyl-1,2,3-trimethyl-4-nitrobenzene. Solvolysis of the dienyl acetate in acidified aqueous acetone and acidified methanol affords the diastereomers of the dienols and the dienyl methyl ethers, respectively. The dienyl methyl ethers are also formed from the dienyl acetate in neutral methanol and again on reaction with methanolic sodium methoxide. The dienols isomerize (epimerize) in acidified aqueous acetone. Reaction of the dienyl methyl ethers in aqueous methanol, or prolonged reaction in methanol, results in the formation of methyl-1,2,3-trimethylphenyl ether. Similar cleavage of the tert-butyl group is the main reaction on solvolysis of the dienyl acetate in aqueous acetic acid. Under more acidic conditions the dienyl acetate gives 5-tert-butyl-2,3-dimethylbenzyl nitrite and lesser amounts of 5-tert-butyl-2,3-dimethylphenylnitromethane and 5-tert-butyl-2,3-dimethylbenzyl acetate. In trifluoromethanesulfonic and fluorosulfonic acids 5-tert-butyl-1,2,3-trimethyl-4-nitrobenzene is the major product.

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Photochemical reactions of azo compounds. VII. Studies of the photochemical reactions of azobenzene under various acidic conditions

Australian Journal of Chemistry ◽

10.1071/ch9661445 ◽

1966 ◽

Vol 19 (8) ◽

pp. 1445 ◽

Cited By ~ 6

Author(s):

GE Lewis ◽

RJ Mayfield

Keyword(s):

Acetic Acid ◽

Acetic Anhydride ◽

Sulphuric Acid ◽

Photochemical Reaction ◽

Acetyl Chloride ◽

Photochemical Reactions ◽

Aluminium Chloride ◽

Azo Compounds ◽

High Yield ◽

Acidic Conditions

An investigation has been made of the photochemical and dark reactions of azobenzene in acetic acid-ferric chloride and acetic acid-aluminium chloride mixtures for comparison with the corresponding reactions of azobenzene in sulphuric acid. The photochemical reactions resulted in cyclodehydrogenation of azobenzene to benzo[c]cinnoline, and small quantities of reduction products of azobenzene were also isolated. The formation of reduction products was again observed in the dark reactions, but there was no sign of cyclodehydrogenation. The significance of these observations is now discussed. Irradiation of azobenzene in acetyl chloride, or in acetic anhydride containing hydrogen chloride, resulted in a novel photochemical reaction in which NN?-diacetyl-4-chlorohydrazobenzene was formed in high yield.

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Vapor-liquid equilibria in mixtures containing an associating substance. III. Binary and ternary systems of water, acetic acid and acetic anhydride at 400 mm Hg

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19560269 ◽

1956 ◽

Vol 21 (2) ◽

pp. 269-280 ◽

Cited By ~ 8

Author(s):

J. Marek

Keyword(s):

Acetic Acid ◽

Acetic Anhydride ◽

Ternary Systems ◽

Vapor Liquid Equilibria ◽

Binary And Ternary Systems ◽

Vapor Liquid

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An unusual reaction of a bridged triterpenoid α-diketone with acetic anhydride

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19912917 ◽

1991 ◽

Vol 56 (12) ◽

pp. 2917-2935 ◽

Cited By ~ 1

Author(s):

Eva Klinotová ◽

Václav Křeček ◽

Jiří Klinot ◽

Miloš Buděšínský ◽

Jaroslav Podlaha ◽

...

Keyword(s):

Acetic Acid ◽

Nmr Spectroscopy ◽

Acetic Anhydride ◽

Spectral Methods ◽

X Ray Diffraction ◽

X Ray ◽

Mild Conditions ◽

Condensation Products ◽

Unsaturated Lactones ◽

C Nmr

3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.

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