Amines heteroaromatic, reduction

Deoxygenation of N-oxides reduction of ArNO2. An Mo(IIl) species obtained by reduction of MoC15 with zinc in aqueous THF reduces aromatic N-oxides in 45 65% yield. The reagent also reduces aromatic and heteroaromatic nitro compounds lo amines in 30-70% yield. 

The reagent combination TiCl(0 Pr)3-NaBH(OAc)3 performs reductive amination of aldehydes by electron-deficient and heteroaromatic primary amines, to give secondary amine.317... 

Other fused azepines, with aromatic (e.g. 94a,b) or heteroaromatic fused rings (e.g. 94c,d) have been prepared via the Af-acyliminium ion intermediate 93 in high yields lactam reduction then yielded the respective amines 95a,b and 95c,d [01H1519]. An intramolecular Friedel-Crafts reaction has been used to synthesise the fused azepinone 99 (S,S configuration) from 98, the latter being prepared from the diastereopure a-hydroxylactam 96, via the acid 97 [02H449],... 

The electrochemical behavior of azomethine derivatives, e.g., oximes, of heteroaromatic carbonyl compounds is much like that of the corresponding benzene derivatives.91 Pyridine aldoximes271-274 and ketoximes275 are reduced in acid solution by a four-electron reaction to the amine. The reaction mechanism is probably, as in other oximes,01 a reduction of the protonated compound with cleavage of the N-0 bond, followed by saturation of the C=N double bond. The amine is often further reducible at a more negative potential (Section VI, E). 

Ruthenium-based catalysts display some utility for electrophilic amination of heteroaromatic substrates. Che and coworkers have found that [Ru(TTP)(CO)J in combination with PhI=NTs will oxidize arenes such as furan, indole, and pyrrole (Fig. 13) [68]. Reactions occur optimally under the action of ultrasound, a rather unusual addendum to the standard protocol for C-H amination. More intriguingly still, iV,A-ditosylated products are isolated in most instances, a finding that is not easily resolved mechanistically. As the substrate profile for this amination process involves only electron-rich heteroaromatics, aziridination of the arene nucleus would seem a likely step along the reaction coordinate. Interestingly, no amination product is observed when stoichiometric [Ru(TMP)(NTs)2] (TMP = tetra(2,4,-6-trimethylphenyl)porphyrin) is mixed with either furan or /V-phenylpyrrole. though a reduction of the starting Ru(VI) complex to a Ru(IV) species is noted... 

Direct amination of 3(2//)-pyridazinones occurs when they are heated with hydrazine hydrate and this is a convenient route to many 4-amino-6-substituted-3(2//)-pyridazinones (Scheme 11). The reaction generally gives high yields and amination is regiospecific when the 6-position is occupied by an aromatic or heteroaromatic ring, but the parent 3(2/ -pyridazinone gives a mixture of the 4- and 5-amino-3(2//)-pyridazinones. The reaction tolerates jV-methyl substitution of the pyridazinone, but is sensitive to steric factors the presence of a 5-substituent causes a marked reduction in reaction rate, and amination does not occur with 4-phenyl-3(2//)-pyridazinone. With maleic hydrazide 4-hydrazination occurs, possibly by displacement of an intermediate amino compound or by oxidation of an intermediate 4,5-dihydro-4-hydrazino adduct both 4-hydrazino- and... 

Aromatic and heteroaromatic amines have been prepared in a one-pot process by treatment of Grignard or organolithium reagents with diphenyl phosphorazidate followed by reductive work-up of the... 

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