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.

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.

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.

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.

An efficient synthesis of pterosin C and other pterosins

1984 ◽  
Vol 62 (10) ◽  
pp. 1945-1953 ◽  
Author(s):  
Kam-Mui Eva Ng ◽  
Trevor C. McMorris
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Methyl Ether ◽  
Sodium Acetate ◽  
Synthetic Route ◽  
Efficient Synthesis ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans

A versatile synthetic route to pterosins, sesquiterpenoid indanones present in bracken, Pteridiumaquilinum, has been developed. The route is exemplified by the synthesis of (2S,3S)-pterosin C by Friedel–Crafts bisacylation of the methyl ether of 2-(2,6-dimethylphenyl)ethanol with methylmalonyl chloride. Demethylation of the resulting 1,3-indandione and reduction with zinc and acetic acid in the presence of acetic anhydride and sodium acetate afforded a mixture of racemic cis and trans isomers of pterosin C diacetate, which was hydrolysed to the corresponding pterosins. Separation and resolution via the S-(+)-α-phenylbutyric esters gave (2S,3S)-pterosin C and (2R,3R)-pterosin C. Other pterosins were prepared as racemates from the 1,3-indandione.

Studies in Thiohydantoin Chemistry. I. Some Aspects of the Schlack-Kumpf Reaction

1996 ◽  
Vol 49 (5) ◽  
pp. 541 ◽  
Author(s):  
BM Duggan ◽  
RL Laslett ◽  
JFK Wilshire
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Acetic Anhydride ◽  
Ammonium Thiocyanate ◽  
Sodium Thiocyanate ◽  
Side Chains ◽  
Derivatives Of

An investigation has been carried out into the Schlack-Kumpf reaction, i.e., the reaction of amino acids with a mixture of acetic anhydride, acetic acid and sodium thiocyanate (occasionally ammonium thiocyanate was used). Particular emphasis was placed on the reactions with amino acids containing sensitive or functional side chains, i.e., serine, threonine , arginine , proline , lysine, histidine , cysteine , and aspartic and glutamic acids. The reaction of serine, and of certain of its O- and N-substituted derivatives, takes an unusual course to give an acetylated thiohydantoin derivative of cysteine. Correspondingly, threonine gives an acetylated thiohydantoin derivative of β- methylcysteine. Similar reactions occurred with the 3-phenylthiohydantoin derivatives of serine and of threonine to give acetylated thiohydantoin derivatives of cysteine and of β-methylcysteine respectively.

The Nitration of α- and β-Acylnaphthalenes

1995 ◽  
Vol 48 (12) ◽  
pp. 1969 ◽  
Author(s):  
SD Barker ◽  
K Wilson ◽  
RK Norris
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Acetic Anhydride ◽  
Nitro Compound ◽  
Nitro Compounds ◽  
The Other ◽  
Coupling Constant ◽  
Significant Extent ◽  
Nitro Derivatives ◽  
High Yields

The nitration of α- and β- acylnaphthalenes with copper(II) nitrate in acetic anhydride or nitric acid/acetic acid mixtures gives high yields of the corresponding mononitro compounds. The assignment of constitution to these products is made on the basis of extensive 1H n.m.r. chemicl shift and coupling constant data. In the case of α- acylnaphthalenes, with the notable exception of α- pivalonaphthone, nitration occurs in the α-positions of the unsubstituted ring to give mixtures of 5- and 8-nitro compounds. α- Pivalonaphthone gives appreciable amounts of the 4-nitro compound and also of the 8-nitro compound. This result indicates that the pivaloyl group does not shield the 8-position sterically to any significant extent and is effectively electronically neutral, unlike the other acyl substituents , in allowing attack at the α-position (position 4) of the acylated ring. This result is ascribable to the lack of coplanarity of the pivaloyl group with the naphthalene system. All of the β- acylnaphthalenes gave mixtures of 4-, 5- and 8-nitro derivatives in proportions that did not vary significantly with the nature of the acyl group.

Hot-Tube Reactions of Dehydroabietic Acid with Ketene-Producing Reagents. Pyrolysis of the Acid Chloride and Symmetrical and Mixed Anhydride Derivatives of Dehydroabietic Acid

1973 ◽  
Vol 51 (19) ◽  
pp. 3236-3241 ◽  
Author(s):  
Ray F. Severson ◽  
Walter H. Schuller
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Acid Chloride ◽  
Acetyl Chloride ◽  
Dehydroabietic Acid ◽  
Mixed Anhydride ◽  
Temperature Range ◽  
Acid Isomerization ◽  
Derivatives Of ◽  
Isopropenyl Acetate

Dehydroabietic acid (1a) was reacted with diketene, acetic acid, acetic anhydride, isopropenyl acetate, acetyl chloride, and acetone on Vycor rod at 450 °C in a hot tube. Dehydroabietic anhydride (1b) and acetyl dehydroabietate (1c) were pyrolyzed at 450 °C and dehydroabietyl chloride (1d) was pyrolyzed over a temperature range of 290–500 °C. The major olefin products resulting from decarboxylation of the various derivatives were 19-norabieta-4,8,11,13-tetraene (2), 19-norabieta-4(18),8,11,13-tetraene (3), 19-norabieta-3,8,11,13-tetraene (4), and cis-1,10a-dimethyl-7-isopropyl-1,2,3,9,10,10a-hexahydrophenanthrene (5). High conversions to these compounds were obtained. In the presence of the ketene-producing reagents the olefins were oxidized to yield substantial amounts of retene (6), compounds 2 and 5 being the most readily dehydrogenated. The acid isomerization of 2, 3, 4, and 5 was studied using p-toluenesulfonic acid in toluene at 110 °C.

Adduct Intermediates in the Side-chain Nitration of 1,4-Dimethylnaphthalene

1972 ◽  
Vol 50 (24) ◽  
pp. 3988-3992 ◽  
Author(s):  
Alfred Fischer ◽  
Alan Leslie Wilkinson
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Acetic Anhydride ◽  
Room Temperature ◽  
Methylene Chloride ◽  
Side Chain ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans ◽  
Naphthyl Acetate

cis and trans isomers of 1,4-dimethyl-4-nitro-1,4-dihydro-1-naphthyl acetate (1) have been isolated from a mixture of 1,4-dimethylnaphthalene and nitric acid in acetic anhydride by quenching at −40°. At room temperature only 1-methyl-4-nitromethylnaphthalene (4) is obtained. The conversion of 1,4-dimethylnaphthalene to 4 and of the cis (1a) and trans (1b) adducts to 4, by nitric acid in acetic anhydride, has been followed by n.m.r. 1,4-Dimethyl-4-nitro-1,4-dihydro-1-naphthyl nitrate (5) appears to be the immediate product from nitration of 1,4-dimethylnaphthalene in acetic anhydride, methylene chloride, or nitromethane. In acetic anhydride 5 is converted into 1. Decomposition of 1 in acetic acid gives 1,4-dimethyl-2-naphthyl acetate and some 4. The formation of 4 in this reaction is suppressed by urea.

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