- Electrochemical synthesis of nitroanilines
-
Alkylamines and amides are readily prepared by nucleophilic aromatic substitution of hydrogen in nitroarenes by electrochemical oxidation. Useful yields (15-85%) are achieved in a simple direct and regioselective amination process. The synthetic method has been examined in the absence and presence of external bases, used to promote the first step of the nucleophilic aromatic substitution reaction, i.e. the nucleophilic attack. In both cases, good results were obtained. The unreacted starting material can easily be recovered at the end of the electrochemical oxidation process. This new method represents an environmentally favourable route to amino- and amido-substituted nitroaromatic compounds.
- Gallardo, Iluminada,Guirado, Gonzalo,Marquet, Jordi
-
p. 251 - 259
(2007/10/03)
-
- A convenient copper-catalyzed direct animation of nitroarenes with 9-alkylhydroxylamines
-
O-Alkylhydroxylamines, particularly O-methylhydroxylamine, aminate nitroarenes in the presence of a strong base and a copper catalyst to give aminonitroarenes in good yields, ortho- or para-Animation with respect to the nitro group takes place, and in some cases the ortho-aminated product is preferentially obtained. With 3-substituted nitrobenzenes where the substituent has a lone pair of electrons, preferential amination occurs at the 2-position to give the sterically most congested 3c-f, 14 and 22g.
- Seko, Shinzo,Miyake, Kunihito,Kavvamura, Norio
-
p. 1437 - 1444
(2007/10/03)
-
- Nitroarylamines via the Vicarious Nucleophilic Substitution of Hydrogen: Amination, Alkylamination, and Arylamination of Nitroarenes with Sulfenamides
-
A new reaction of sulfenamides with electrophilic arenes under basic conditions is described. The σ adducts formed from nitroarenes and the anions of sulfenamides undergo elimination of thiol to produce the corresponding o- and/or p-nitroanilines. This reaction is analogous to the known alkylation and hydroxylation of nitroarenes via the vicarious nucleophilic substitution of hydrogen (VNS). The reaction gives access to a wide range of substituted nitroanilines, nitronaphthylamines, and aminoheterocycles. By means of the reaction with N-alkyl- and N-arylsulfenamides, it is possible to obtain N-alkylnitroanilines and nitrodiarylamines. By varying the structure of sulfenamide and the reaction conditions, particularly the nature and concentration of the base, it is possible to control the orientation of animation.
- Makosza, Mieczyslaw,Bialecki, Maciej
-
p. 4878 - 4888
(2007/10/03)
-
- Terbenzimidazoles: Influence of 2''-, 4-, and 5-substituents on cytotoxicity and relative potency as topoisomerase I poisons
-
Terbenzimidazoles poison the nuclear enzyme topoisomerase I and possess significant cytotoxic activity against several human tumor cell lines. The relative pharmacological activity of 4,5- and 5,6-benzoterbenzimidazoles was compared to that of 5-phenylterbenzimidazole (3). 5,6-Benzoterbenzimidazole is inactive as a topoisomerase I poison and did not exhibit significant cytotoxic activity. In contrast, 4,5-benzoterbenzimidazole retained activity as a topoisomerase I poison but exhibited weak cytotoxic activity relative to 3. While 5-(1-naphthyl)-terbenzimidazole is less potent than 3 as a topoisomerase I poison and cytotoxic agent, 5-(2-naphthyl)terbenzimidazole has comparable activity to 3. The presence of a p-methoxy or p-chloro substituent on the phenyl moiety did not dramatically alter the pharmacological activity of 3. Several analogs of 3 were synthesized wherein the 2''-substituent varied from methyl, ethyl, propyl, isopropyl, phenyl to p-methoxyphenyl. Evaluation of the intrinsic activity of these analogs as topoisomerase I poisons indicates that topoisomerase I poisoning was not diminished by the presence of a methyl, ethyl, propyl, and isopropyl substituent at the 2''-position. Among the various 2''-substituted analogs evaluated, only in the case of 2''-(p-methoxyphenyl)-5-phenylterbenzimidazole was a significant decrease in cytotoxicity observed.
- Kim, Jung Sun,Yu, Chiang,Liu, Angela,Liu, Leroy F.,LaVoie, Edmond J.
-
p. 2818 - 2824
(2007/10/03)
-
- Process for preparing nitroaniline derivatives
-
A process for preparing a nitroaniline derivative comprising a step of reacting an aromatic nitro compound with an O-alkylhydroxylamine or a salt thereof in the presence of a base and optionally a metallic catalyst, which process is industrially advantageous since it provides the nitroaniline derivative from the aromatic nitro compound in a high yield in one step, and the aminating agent used can be obtained from hydroxylamine at a relatively low cost.
- -
-
-
- Process for the preparation of aromatic amines
-
Electrophilic aromatic compounds can be reacted with sulphenamides in the presence of bases to form the corresponding aromatic amines.
- -
-
-
- Amination of Nitroarenes with Sulfenamides via Vicarious Nucleophilic Substitution of Hydrogen
-
Nitroarenes react with sulfenamides RSNH2 in the presence of strong bases to give p- and o-nitroanilines.
- Makosza, Mieczyslaw,Bialecki, Maciej
-
p. 4784 - 4785
(2007/10/02)
-
- Alkylaminonitrobenzenes by Vicarious Nucleophilic Amination with 4-(Alkylamino)-1,2,4-triazoles
-
A series of 4-(alkylamino)-1,2,4-triazoles transfer the alkylamino group to the 4-position of nitrobenzene and various 3-substituted nitrobenzenes, with no detectable ortho substitution.By contrast 2-nitrothiophene reacts in the 3-position and 2-nitronaphthalene in the 1-position; 1-nitronaphthalene gives a mixture of products derived from dominant 2- with some 4-substitution.The orientations are discussed and rationalized.
- Katritzky, Alan R.,Laurenzo, Kathleen S.
-
p. 3978 - 3982
(2007/10/02)
-