Facile Transfer Hydrogenation of Azo Compounds to Hydrazo Compounds and Anilines by Using Raney Nickel and Hydrazinium Monoformate
作者:H. S. Prasad、Shankare Gowda、D. Channe Gowda
DOI:10.1081/scc-120027231
日期:2004.12.31
Abstract Azo compounds are conveniently reduced to either partially reduced hydrazo compounds or completely reduced anilines by employing Raney nickel in presence of hydrazinium monoformate depending upon reaction conditions. The other reducible moieties like ‒COOH and halogens are tolerated. The reduction process is selective, rapid and high yielding.
Self-assembled palladium–organic composite nanofibers and their applications as a recyclable catalyst
作者:Tanmay Bera、Jiyu Fang
DOI:10.1039/c3ra41894d
日期:——
We report the formation of palladium nanoparticle (PdNP)âlithocholic acid (LCA) composite nanofibers by the self-assembly of Pd2+-coordinated LCA molecules and an ex situ reduction. The ex situ reduction by sodium borohydride or ascorbic acid produces the composite nanofibers with PdNPs grown on the surface of LCA nanofibers. The catalytic activity of the PdNPâLCA composite nanofibers in the decolourization of 4-phenyl azo benzoic acid is investigated. We find that the composite nanofibers can be recycled without significantly losing their catalytic activities.
Structure requirements for anaerobe processing of azo compounds: Implications for prodrug design
作者:Jason Gavin、Juan F. Marquez Ruiz、Kinga Kedziora、Henry Windle、Dermot P. Kelleher、John F. Gilmer
DOI:10.1016/j.bmcl.2012.10.014
日期:2012.12
This Letter generalizes the metabolism of the azo class of compounds by Clostridium perfringens, an anaerobe found in the human colon. A recently reported 5-aminosalicylic acid-based prednisolone prodrug was shown to release the drug when incubated with the bacteria, while the para-aminobenzoic acid (PABA) based analogue did not. Instead, it showed a new HPLC peak with a relatively close retention time to the parent which was identified by LCMS as the partially reduced hydrazine product. This Letter investigates azoreduction across a panel of substrates with varying degrees of electronic and steric similarity to the PABA-based compound. Azo compounds with an electron donating group on the azo-containing aromatic ring showed immediate disproportionation to their parent amines without any detection of hydrazine intermediates by HPLC. Compounds containing only electron withdrawing groups are partially and reversibly reduced to produce a stable detectable hydrazine. They do not disproportionate to their parent amines, but regenerate the parent azo compound. This incomplete reduction is relevant to the design of azo-based prodrugs and the toxicology of azo-based dyes. (C) 2012 Elsevier Ltd. All rights reserved.
Pietra, Annali di Chimica, 1957, vol. 47, p. 410,413
作者:Pietra
DOI:——
日期:——
261. Derivatives of 3 : 5-dioxopyrazolidine likely to possess therapeutic activity