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Further, T3P has also been employed to activate the hydroxamtes leading to isocyanates via Lossen rearrangement 34. NHC–catalyzed Synthesis of Hydroxamic Acids N-Heterocyclic carbene NHC catalyzed amidation of a variety of aryl, alkyl, alkenyl and heterocyclic aldehydes with nitroso compounds is a powerful method for the synthesis of N-aryl hydroxamic acids in excellent yields. Chemoselective Esterificaiton Using Imidazole Carbamates Imidazole carbamates and ureas are used as chemoselective esterification and amidation reagents. A simple synthetic procedure allows the conversion of a wide variety of carboxylic acid to hydroxamates. Synthesis of Weinreb Amides Using Triazime Intermediates De Luca et al 37 reported the successful large scale synthesis of weinreb amide through a convenient and simple one-flask method via 2-chloro-4,6-dimethoxy-1,3,5-triazine intermediate 20. desferrioxamine B, fosmidomycin, siderophores 28 and allergic diseases. 29 The wide biological application of hydroxamates necessitates the review of its synthesis and biological applications. General Synthesis of Weinreb Amides Hydroxamic acids are prepared usually from esters or acid chlorides or carboxylic acids.2.1. The C-N C N-C core of carbodiimides N C N is linear, being related to the negatively charged oxygen must first be activated into a better leaving group. Cipemastat, marimastat, periostat, ilomastat and batimastat are all hydroxamate-based inhibitors of matrix metalloproteinase and are by so used in management of cardiovascular diseases. Hydroxamic acids have been the source of much biochemical interest in recent years reflecting the fact that they demonstrate a wide variety of biological activities. Email: Copyright 2014 Scientific Academic Publishing. There are hydroxamates with reported anti-HIV activity such as the hydroxyurea which acts as inhibitors of cellular enzyme ribonucleoside diphosphate reductase. 1 Hydroxamates have high affinity for ferric ions that nature has evolved families of hydroxamic acids to function as no N-binding compounds siderophores in bacteria.

Ugwuja3 1Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Nigeria 2National Centre for Energy Research and Development, University of Nigeria, Nsukka, Nigeria 3Department of Chemical Sciences, Federal University, Wukari, Nigeria Correspondence to: David I. Introduction Hydroxamates are class of organic compounds bearing the functional group RICON OH RII as organic residues and CO as a carbonyl group.

Removal of the acetyl groups known as hypo acetylation restores the normal positive change to the histone and therefore allows the DNA to condense and prevent transcription.

This silencing can become permanent if the unprotected lysines are then methylated.

This process increases the amount of RNA present in the cell and their respective encoded proteins. Synthesis of Trichostatin A Trichostatin A was the first naturally occurring HDI to be discovered. It causes an increase in acetylated histones in a variety of mammalian tumor cell line.

45 Trichostatin A was shown to be a selective histone deacetylase inhibitor, reversibly inhibiting classes I, II and IV types of HDAC while not affecting class III. 46 The first portion of the synthesis is shown in scheme 9.