Reduction substituted

Aminophenols are either made by reduction of nitrophenols or by substitution. Reduction is accompHshed with iron or hydrogen in the presence of a catalyst. Catalytic reduction is the method of choice for the production of 2- and 4-aminophenol (see Amines BY reduction). Electrolytic reduction is also under industrial consideration and substitution reactions provide the major source of 3-aminophenol. 

Like aldehyde, the ketone function provides sufficient activation on an aromatic ring for the nucleophiUc substitution. Reduction of the carbonyl group after incorporation of the F-fluoride ion yields F-alkyl aromatics [177]. This methodology using F for trimethylammonium exchange, then reduction of the carbonyl compound, have proved to be useful for the synthesis of a [2- F]fluo-rophenol at high specific activity [141] (Scheme 39). 

In general, Tc complexes are prepared by concomitant substitution/reduction or oxidation processes, rather than from direct substitution of weak labile ligands such as halides. The only exceptions are reactions with ffcNCU]. This is due to the lack of reactive but reasonably stable direct precursors for this oxidation state and, as a consequence, all other Tc chemistry necessarily arises from redox processes. 

The kinetics of formation of nitroprusside from [Fe VCN)5(H20)] indicate a mechanism of complex formation in which outer-sphere reduction to [Fe (CN)5(Fl20)] precedes substitution."" Reduction of the dimeric pentacyanoferrate(III) anion [Fe2(CI io]" by thiourea is a multi-stage process the first step is one-electron transfer to give [Fe2(CN)io], which dissociates to give [Fe(CN)5(tu)]2- and [Fe(CN)5(H20)] -.""... 

E. Briard, V.W. Pike, Substitution-reduction An alternative process for the [F-18]N-(2-fluoroethylation) of anilines, J. Label. Compds Radiopharm. 47 (2004) 217-232. 

Hall and Polis 7 prepared a series of polyarylamines using an aromatic nucleophilic substitution-reduction sequence (Scheme 4.20). Hence, 2,4-dinitrofluorobenzene 66 was treated with />-diaminobenzene to afford tetranitro 67, which was reduced to give the corresponding first generation, diamine 68. Repetition of this sequence afforded the second generation tetradecaamine 69. These starburst polyarylamines were complexed with iodine to form semiconducting materials and were the first dendrimers to be examined by cyclic voltammetry. 

A. G. Sutherland, One or More CH Bond(s) Formed by Substitution Reduction of C-Halogen and C-Chalcogen Bonds, in Comprehensive Organic Functional Group Transformations (A. R. Katritzky, O. Meth-Cohn, C. W. Rees, Eds.), Vol. 1,1, Elsevier Science, Oxford, U. K., 1995. 

The stereoselectivity of the reduction of vinylogous urethane 4, as shown in Scheme 2, may be attributed to steric hindrance, by which the catalytic hydrogenation occurs from the less hindered site (a-face) of 4 to give an all cw-substituted reduction product (Fig 2). 

When the cyano (—C=N) group is added and reduced, the resulting amine has an additional carbon atom. In effect, the cyanide substitution-reduction process is like adding —CH2 —NH2. The following synthesis makes 2-phenylethylamine, which we also made by the azide synthesis ... 

The photochemical reactions of some a-arylvinyl bromides (31), in acetic acid in the presence of sodium acetate and tetraethylammonium bromide (labeled with 8zBr) give nucleophilic substitution, reductive debromination, cis-stilbene photocyclization, and oxidation as the primary pathways to product... 

The majority of organometallic complexes contain 18 electrons see Bonding Energetics of Organometallic Compounds). These complexes undergo ligand substitution, reductive elimination, and electron-transfer reactions see Electron Transfer in Coordination Compounds). Each type of reaction will be covered in the following sections. 

Nucleophilic substitition of aromatic halides with trimethylsilyl anions competes with reduction. The ratio of substitution/reduction increases in the direction of I < Br < Cl, and appears relatively insensitive to the metal cations (30a,b). When an electrophile is a poorer electron acceptor, such as Ph3GeBr, nucleophilic substitution proceeds smoothly to form the coupling product in good yield ( ). 

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