Reduction of aryl nitro compounds with aluminiumNH4Cl: effect of ultrasound on the rate of the reaction

A comparative study and development of an improved method for the reduction of nitroarenes into arylamines by Al/NH4X (X = Cl, Br, I) in methanol under ultrasonic conditions

“…In our opinion this method is superior to our previous method of reduction by Al/NH 4 Cl [1] and some of the existing methods of reduction which employ expensive and hazardous reagents. A plausible mechanism for the reduction of nitroarenes with Al/ NH 4 X has been envisaged.…”

“…In our earlier report [1], we have described the reduction of nitroarenes by Al/NH 4 Cl to the corresponding amines. Recently, we have reported the cleavage of azoarenes into arylamines by Al/NH 4 Br [14], and the reduction of nitroarenes into azoarenes and/or arylamines by Al/NaOH in methanol [15] under sonic conditions.…”

“…In an effort to find the mechanistic path, reduction of nitrobenzene was carried out by reacting it with Al/NH 4 Cl in methanol under silent condition as well as under sonication, since one can question the involvement of NH 4 Cl, we thought that, the first step of the reaction involves a single electron transfer from metal to the substrate [1]. Now, we found that the progress of this reaction is slow in comparison to the reaction with NH 4 Br and with NH 4 I.…”

“…Compared to traditional methods, it is more convenient and hence a large number of organic reactions have been reported in the past three decades [1,2]. Ultrasound is beneficial in one or more ways like accelerating a chemical reaction, uses less purified or cruder reagents, initiating reactions without the need of additives or catalysts, avoids forcing conditions like high temperature and high pressure, and for simplifying the reaction by reducing the number of steps, hence, makes a reaction cost effective which matches with Ôgreen chemistryÕ protocols.…”

Ultrasound promoted regioselective synthesis of β-iodoethers from olefin-I2-alcohol

“…In continuation of our work on sonochemically accelerated reactions [3][4][5][6][7], we became interested in the ultrasound promoted preparation of the b-iodoethers for two reasons (i) contradicting reports regarding the usage of metal salts as catalysts: Tl (I), Cu (II), Ce (IV) salts [8][9][10][11][12], whose presence is required to catalyse the reaction, while in another report by Mattos and coworker [13] excess of iodine is sufficient to obtain b-iodoethers in moderate to good yields (ii) to find the effect of ultrasound (35 kHz, in a sonic bath) for catalytic activity on the reaction and the use of metal salts as catalysts in presence of ultrasound.…”