128702-29-4Relevant academic research and scientific papers
Indium metal as a reducing agent in organic synthesis
Pitts,Harrison,Moody
, p. 955 - 977 (2007/10/03)
The low first ionisation potential (5.8 eV) of indium coupled with its stability towards air and water, suggest that this metallic element should be a useful reducing agent for organic substrates. The use of indium metal for the reduction of C=N bonds in imines, the heterocyclic ring in benzo-fused nitrogen heterocycles, of oximes, nitro compounds and conjugated alkenes and the removal of 4-nitrobenzyl protecting groups is described. Thus the heterocyclic ring in quinolines, isoquinolines and quinoxalines is selectively reduced using indium metal in aqueous ethanolic ammonium chloride. Treatment of a range of aromatic nitro compounds under similar conditions results in selective reduction of the nitro groups; ester, nitrile, amide and halide substituents are unaffected. Likewise indium in aqueous ethanolic ammonium chloride is an effective method for the deprotection of 4-nitrobenzyl ethers and esters. Indium is also an effective reducing agent under non-aqueous conditions and α-oximino carbonyl compounds can be selectively reduced to the corresponding N-protected amine with indium powder, acetic acid in THF in the presence of acetic anhydride or di-tert-butyl dicarbonate. Conjugated alkenes are also reduced by indium in THF-acetic acid.
4-NITROBENZYL GROUP FOR PROTECTION OF HYDROXYL FUNCTIONS
Fukase, Koichi,Tanaka, Hideo,Torii, Sigeru,Kusumoto, Shoichi
, p. 389 - 392 (2007/10/02)
Versatile use of 4-nitrobenzyl group for protection of hydroxyl functions is described.It can be removed selectively in the presence of other benzyl-type protecting groups such as benzyl and 4-methoxybenzyl via reduction into 4-aminobenzyl group followed by electrochemical oxidation.Very clean oxidative cleavage of 4-aminobenzyl group could also be effected with 2,3-dichloro-5,6-dicyanobenzoquinone after N-acetylation.
