ABSTRACT
The syntheses of the title compounds demonstrate a privileged introduction of a nitroso (and a hydroxyl via the Baudisch reaction) group to an aromatic ring. These complexes first appeared in the literature as early as 1939, and a range of applications has subsequently been published. However, optimisations of the preparative sequences were not considered, and as such, the reactions have seldom been utilised in recent years; indeed, there remains confusion in the literature as to how such complexes form. In this review, we aim to demystify the misunderstanding surrounding these remarkable complexes and consider their renewed application in the 21st century.
Subject(s)
Chemistry Techniques, Synthetic , Coordination Complexes/chemistry , Nitroso Compounds/chemistry , Coordination Complexes/chemical synthesis , Molecular Structure , Nitroso Compounds/chemical synthesisABSTRACT
A simple protocol yielding ortho-substituted nitrosophenols from phenols is demonstrated, in the form of copper(II) bis(nitrosophenolato) complexes. The developed methodology was applied to a range of substrates, confirming the role of the copper in both the formation and protection of the challenging 1, 2-substitution pattern. Using polymer supported thiourea, the Cu could be stripped from the complexes and thus enabled the isolation or identification of the uncoordinated ligands and their decomposition products, in yields generally low in line with the intrinsic high reactivity of 2-nitrosophenols. The product complexes are useful intermediates as demonstrated in revisiting a formal [4 + 2] cycloaddition with dimethylacetylene dicarboxylate to synthesise bicyclic products in variable yields, revealing the product has a novel structure different from those previously reported in the literature.
Subject(s)
Copper/chemistry , Nitrosation , Organometallic Compounds/chemistry , Heterocyclic Compounds/chemistry , Ligands , Models, Molecular , Molecular StructureABSTRACT
Continuous flow processing was applied for the rapid replacement of an aromatic amino group with a hydride. The approach was applied to a range of aromatic heterocycles, confirming the wide scope and substituent-tolerance of the processes. Flow equipment was utilized and the process optimised to overcome the problematically-unstable intermediates that have restricted yields in previous studies relying on batch procedures. Various common organic solvents were investigated as potential hydride sources. The approach has allowed key structures, such as amino-pyrazoles and aminopyridines, to be deaminated in good yield using a purely organic-soluble system.
Subject(s)
Heterocyclic Compounds/chemistry , Hydrocarbons, Aromatic/chemistry , Rheology , Catalysis , Nitrites/chemistry , SolventsABSTRACT
We present a case of a newborn male with seizures who on subsequent radiographs was shown to have bilateral acromial fractures. These are uncommon fractures and are described in association with nonaccidental injury (NAI). However, in this case NAI was thought unlikely due to continuous hospitalisation of the boy. The possible aetiologies are discussed.