Hydrazine-mediated Reduction of Nitro and Azide Functionalities Catalyzed by Highly Active and Reusable Magnetic Iron Oxide Nanocrystals

Abstract

Iron oxide (Fe3O4) nanocrystals generated in situ from an inexpensive and readily available iron source catalyze the reduction of nitroarenes to anilines with unparalleled efficiency. The procedure is chemoselective, avoids the use of precious metals, and can be applied under mild reflux conditions (65 or 80 °C) or using sealed vessel microwave heating in an elevated temperature regime (150 °C). Utilizing microwave conditions, a variety of functionalized anilines have been prepared in nearly quantitative yields within 2-8 min at 150 °C, in a procedure also successfully applied to the reduction of aliphatic nitro compounds and azides. The iron oxide nanoparticles are generated in a colloidal form, resulting in homogeneous solutions suitable for continuous flow processing. Selected examples of anilines of industrial importance have been prepared in a continuous regime using this protocol.

Iron oxide nanoparticles supported on activated carbon fibers catalyze chemoselective reduction of nitroarenes under mild conditions

“…No intermediates were detected by GC analysis. While such a high selectivity has been already reported for unsupported Fe oxide catalysts, the activity of our Fe 2 O 3 /ACF catalysts is at least one order of magnitude higher as compared to the previously reported results [7,8,10,25,27,30,31].…”

An efficient and high-yielding protocol for the production of Regorafenib via a new synthetic strategy

“…During the process for the reduction of 6, four typical methods utilizing hydrazine hydrate [14][15][16], iron powder [17,18], zinc dust [19][20][21] and palladium [22][23][24] were screened (Table 3). At the initial stage, reduction of 6 with hydrazine hydrate was incapable of thoroughly converting nitro to amino, along with the The optimization results were estimated by detecting the purity of the next-step product 7 and the two- An efficient and high-yielding protocol for the production… formation of impurities 7e and 7f (Fig.…”

Nitrogen and oxygen-doped metal-free carbon catalysts for chemoselective transfer hydrogenation of nitrobenzene, styrene, and 3-nitrostyrene with hydrazine

“…Beier et al used supported platinum particles for reduction of 3-nitrostyrene by hydrogen and showed that the selectivity to vinylaniline was enhanced in the presence of basic ionic liquid, which suppressed its further hydrogenation to ethylaniline [20], similar to the present treated AC surface of basic nature. [8,12,14] Probably, those effects on the adsorption of the substrates and the reactivity of the reducing agent would be responsible for the catalytic performance of nitrogen-and oxygen-doped AC materials in the chemoselective hydrogenation of nitrobenzene, styrene, and 3-nitrostyrene. It is interesting that the doping of hetero atoms to the surface of carbon-based catalysts, which produces polar sites (C-N, C-O) on their surface, is an effective way in promoting organic synthetic reactions and controlling their product distribution patterns.…”

“…The reduction of aliphatic and aromatic nitro compounds by hydrazine was studied by Gowda et al [12,13] using zinc and magnesium catalysts and by Kappe et al [14] using iron oxide nanocrystals.…”