- Specific features of nucleophilic substitution in 1-chloro-3,4- dinitrobenzene
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Effects of the solvent, temperature, and nucleophile nature on the selectivity of nucleophilic substitution in 1-chloro-3,4-dinitrobenzene were studied, and optimal conditions were found for the synthesis and isolation of particular products.
- Zotova,Kushakova,Kuznetsov,Rodin,Garabadzhiu
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p. 1473 - 1476
(2007/10/03)
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- Reaction of Mono-, Di-, and Trichloronitrobenzenes with N-Methyl Substituted Cyclic Tertiary Amines under High Pressure
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The reactions of mono-, di-, and trichloronitrobenzenes with 1-methylpyrrolidine under high pressure gave products of demethylation and ring-opening through a quaternary pyrrolidinium chloride intermediate formed by the SNAr reaction.On the other hand, the reactions with 1-methylpiperidine and 4-methylmorpholine gave only demethylation products.The selectivities of the resctions of 1-methylpyrrolidine with these chloronitrobenzenes were found to be effected by the neighboring substituent to the pyrrolidinium group.
- Ibata, Toshikazu,Shang, Muhong,Demura, Tetsuo
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p. 2717 - 2726
(2007/10/03)
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- Aromatic Nucleophilic Substitution of Halobenzenes with Amines under High Pressure
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The nucleophilic substitution reactions of aromatic halides having electron-attracting groups on ortho or para position with various primary and secondary amines were accelerated by high pressure to give the corresponding N-substituted anilines in high yields.The bulkiness of amines affects its reactivity to lower the yields of the products.Although the secondary amines are usually less reactive than primary amines, cyclic secondary amines such as morpholine, piperidine, and pyrrolidine were found very reactive. 1,4-Diazabicyclooctane and quinuclidine gave N-quarternary ammonium halides in high yields in contrast to the low reactivity of acyclic tertiary amines.Dichloro- and trichloro-nitrobenzenes also react with diethylamine, pyrrolidine, and morpholine to give mono-, di-, and trisubstitution products depending upon the amount of amine and the position of nitro group in these chlorides.
- Ibata, Toshikazu,Isogami, Yasushi,Toyoda, Jiro
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- Stereoelectronic Effects in Tertiary Amine Nitrosation: Nitrosative Cleavage vs. Aryl Ring Nitration
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The nitrosation (acetic acid) of N-(4-chlorophenyl)pyrrolidine gives at least 30percent N-(4-chloro-2-nitrophenyl)pyrrolidine while the corresponding aryldibenzylamine gives no nitration and only nitrosative dealkylation at nitrogen.This difference in reaction site has been probed with N-(4-chlorophenyl)diethylamine.This substance undergoes competitive ring nitration to N-(4-chloro-2-nitrophenyl)diethylamine (50percent) and nitrosative dealkylation to (4-chlorophenyl)ethylnitrosamine (50percent).The former compound nitrosates further to give (4-chloro-2-nitrophenyl)ethylnitrosamine.This substance denitrosates to give the corresponding secondary amine.The reactivity differences result from stereoelectronic factors controlling the amine nitrogen unshared pair delocalization into the aryl ring.This interpretation is supported by 13C NMR data and mechanistic arguments.
- Leoppky, Richard N.,Tomasik, Witold
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p. 2751 - 2757
(2007/10/02)
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