A practical and selective reduction of nitroarenes using elemental sulfur and mild base

Highly Chemo‐ and Regioselective Reduction of Aromatic Nitro Compounds Catalyzed by Recyclable Copper(II) as well as Cobalt(II) Phthalocyanines

“…In general, dehalogenation of halogen-substituted aromatic nitro compounds takes place with the earlier reported methods such as hydrogenation [2c] or PdA C H T U N G T R E N N U N G (OAc) 2 /PMHS [7] and S 8 /mild base. [12] However, in the present study a selective reduction of the nitro halide was observed. A series of aromatic nitro substrates containing other functional groups such as methoxy, acid, nitrile, aldehyde, ester, amide, methyl, hydroxy, ketone, lactone and heterocycle was also successfully reduced, with > 99% chemoselectivity and > 99% conversion (Table 3, entries 7-22).…”

“…[1] Numerous methods have been developed to accomplish this transformation including catalytic hydrogenation, [2] sodium borohydride/catalyst, [3] hydrazine/catalyst, [4] and metals such as iron, tin, or zinc. [5] Over the last years, a variety of other catalytic systems such as Mo(CO) 6 /DBU, [6] PdA C H T U N G T R E N N U N G (OAc) 2 /PMHS, [7] Sm/I 2 , [8] Sm/1,1'-dioctyl-4,4'-bipyridinium dibromide, [9] Sm/NH 4 Cl, [10] Cu nanoparticles/HCOONH 4 , [11] S 8 / NaHCO 3 , [12] HI [13] and silane/oxorhenium complexes [14a] have been reported. However, most of the synthetic methods lack the desired chemoselectivity over other functional groups that are often present in the substrates such as acid, aldehyde, ester, alkene, halide, benzyl, nitrile and, also, the desired regioselectivity in the reduction of dinitro compounds.…”

Magnetische Trennung von organischen Verbindungen durch kovalent funktionalisierte Cobaltnanopartikel

“…Diese Beobachtung schließt die Physisorption von Chlorbenzol auf den Graphitschichten aus. Das Fehlen von Azogruppen (ñ = 1400-1500 cm À1 ) [31] bestätigt frühere Untersuchungen über die Diazotierung von Kohlenstoffnanoröhren und spricht für einen radikalischen Reaktionspfad nach Dyke et al [32] [35] folgend, wurden die Nitro-zu Aminogruppen reduziert. (Abbildung 5, Schema 1).…”

Elemental Sulfur: A Simple, Economic, and Versatile Reagent

“…6 The process takes advantage of the capacity of sulfur to be an inexpensive 2-electron reductant. The reaction conditions are also notable for their compatibility with a range of functional groups and use of a mild base.…”