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

1976 ◽  
Vol 54 (24) ◽  
pp. 3978-3985 ◽  
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.

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

1975 ◽  
Vol 53 (11) ◽  
pp. 1570-1578 ◽  
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.

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

1978 ◽  
Vol 56 (2) ◽  
pp. 258-266 ◽  
Author(s):  
Alfred Fischer ◽  
Khay Chuan Teo
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Nitro Group ◽  
Tert Butyl ◽  
Acidic Conditions ◽  
Group Migration

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.

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

1974 ◽  
Vol 52 (8) ◽  
pp. 1231-1240 ◽  
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.

Nitration of 1-chloro-2,3-dimethylbenzene in acetic anhydride. Formation and rearomatization of adducts

1978 ◽  
Vol 56 (8) ◽  
pp. 1063-1068
Author(s):  
Alfred Fischer ◽  
Colin Campbell Greig
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Nitrous Acid ◽  
Major Product ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Nitro Derivatives ◽  
Subsequent Elimination ◽  
And Migration ◽  
Cis And Trans

Nitration of l-chloro-2,3-dimethylbenzene in acetic anhydride gives the cis and trans isomers of 3-chloro-4,5-dimethyl-4-nitrocyclohexa-2,5-dienyl acetate (29%) and l-chloro-2,3-dimethyl-4-nitro- (46%), -5-nitro- (5%), and -6-nitrobenzene (20%). In formic acid and acidified methanol, exchange of acetate for formate and methoxyl, respectively, occurs and the diastereoisomers of 3-chloro-4,5-dimethyl-4-nitrocyclohexa-2,5-dienyl formate and methyl ether, respectively, are formed. Rearomatization of each isomer of 3-chloro-4,5-dimethyl-4-nitrocyclohexa-2,5-dienyl acetate in acetic acid results in initial isomerization to form the pair of diastereoisomers and subsequent elimination of nitrous acid to form 3-chloro-4,5-dimethylphenyl acetate. In 25% trifluoroacetic acid in deuteriochloroform elimination of acetic acid and migration of the nitro group to form 1-chloro-2,3-dimethyl-4-nitro-benzene and a lesser amount of its 6-nitro isomer is the dominant reaction. In the presence of mesitylene the formation of the nitro derivatives is suppressed and 3′-chloro-2,4,4′,5′,6-pentamethylbiphenyl is obtained. It is proposed that cyclohexadienyl cations are significant intermediates in ail of the reactions. Pyrolysis of the adducts gives 1-chloro-2,3-dimethylbenzene as the major product.

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

1978 ◽  
Vol 56 (13) ◽  
pp. 1758-1768 ◽  
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.

An Addition Reaction of Indane with Nitric Acid in Acetic Anhydride

1972 ◽  
Vol 50 (14) ◽  
pp. 2211-2216 ◽  
Author(s):  
A. Fischer ◽  
C. C. Greig ◽  
A. L. Wilkinson ◽  
D. R. A. Leonard
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Nitrous Acid ◽  
Addition Reaction ◽  
Cis And Trans ◽  
Cis Isomer

cis- and trans-5-Acetoxy-7a-nitro-5,7-dihydroindane are formed as well as the 4- and 5-nitroindanes when indane is reacted with nitric acid and acetic anhydride. These adducts both decompose on standing by loss of nitrous acid forming 5-acetoxyindane. The cis isomer is obtained in greater amount and it undergoes elimination less readily than the trans.

Medium-sized cyclophanes, part 59:1 Nitration of [3.3]- and [3.3.3]metacyclophanes — Through-space electronic interactions between two or three benzene rings

2002 ◽  
Vol 80 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Takehiko Yamato ◽  
Koji Tsuchihashi ◽  
Noriko Nakamura ◽  
Mai Hirahara ◽  
Hirohisa Tsuzuki
Keyword(s):  
Acetic Anhydride ◽  
Electronic Interaction ◽  
Reaction Conditions ◽  
Tert Butyl ◽  
Mixed Acid ◽  
Butyl Group ◽  
Tert Butyl Group ◽  
Starting Compound ◽  
Nitration Product ◽  
Fuming Nitric Acid

The two tert-butyl groups of anti-6,15-di-tert-butyl-9,18-dimethoxy[3.3]metacyclophane (anti-4) are both ipso-nitrated even under mild reaction conditions such as copper(II) nitrate in an acetic anhydride solution because of the decreased deactivation of the second aromatic ring by the introduced nitro group. On the other hand, anti-5,13-di-tert-butyl-8,16-dimethoxy[2.2]metacyclophane (anti-1) undergoes replacement of only one tert-butyl group under the same reaction conditions. The higher yields of the twofold ipso-nitration product anti-7 were obtained in nitration of anti-4 with fuming nitric acid or mixed acid (HNO3–H2SO4). Thus, the number of ipso-nitrations at the tert-butyl groups of anti-4 was strongly affected by the reactivity of the nitration reagent. Nitration of the corresponding syn-conformer syn-4 with copper(II) nitrate in an acetic anhydride solution, however, led only to the recovery of the starting compound. The presently developed procedure was further applied to the direct removal of the tert-butyl group by electrophilic substitution of the larger-sized ring macrocyclic metacyclophanes, cone- and partial-cone-tri-tert-butyl[3.3.3]metacyclophanes 11.Key words: [3n]metacyclophanes, conformation, ipso-nitration, through-space electronic interaction, crystal structure.

The structure of organophosphorus compounds. Part XLIII. The molecular structure of cis- and trans-λ3-amino-2,4,6 -tri(Tert-Butyl)Phenyliminophosphines

1990 ◽  
Vol 31 (2) ◽  
pp. 292-300
Author(s):  
A. N. Chernega ◽  
M. Yu. Antipin ◽  
Yu. T. Struchkov ◽  
A. B. Drapailo ◽  
V. D. Romanenko
Keyword(s):  
Molecular Structure ◽  
Organophosphorus Compounds ◽  
Tert Butyl ◽  
Cis And Trans
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