16689-34-2Relevant articles and documents
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Hess,H.-J. et al.
, p. 4040 - 4041 (1963)
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Crystallographic Insights into the Synthesis and Magnetic Properties of Oxoverdazyl Radicals Functionalized by Benzoic Acid
Kumar, Varun,Shova, Sergiu,Maurel, Vincent,Novitchi, Ghenadie,Train, Cyrille
, p. 517 - 524 (2018)
The synthesis and crystallization of two verdazyl radicals, 1,5-dimethyl-3-(4′-carboxyphenyl)-6-oxoverdazyl HIMe and 1,5-diisopropyl-3-(4′-carboxyphenyl)-6-oxoverdazyl HIiPr, are described. The electrochemical studies reveal that the oxidation of the two radicals is reversible, whereas their reduction is irreversible. The EPR spectrum of both radicals essentially exhibits a nine-line pattern related to the mean hyperfine interaction of the unpaired electron with the nitrogen atoms of the verdazyl cycle. The single-crystal X-ray diffraction of the intermediates towards HIiPr allows a fine description of the cyanoborane adduct, which is the key intermediate of this synthesis. The verdazyl radicals themselves are obtained as single crystals. In the case of HIiPr, depending on the solvent, two polymorphs are crystallized. The structure resolution reveals that, in the solid state, the organization of the verdazyl radicals is governed by both H-bonding and π–π interactions and is reminiscent of the H-bonded structures that can be present in solution. Within the 1D π stacks observed in the three compounds, the verdazyl–verdazyl distance varies from 4.88 ? in HIMe to 7.90 ? in HaIiPr. This modulation of the distance strongly influences the antiferromagnetic intermolecular exchange interaction between π-stacked radicals, which goes from J = –90 cm–1 (H = –JΣSiSi+1) for HIMe to –12.96(3) cm–1 for HbIiPr and –0.92 cm–1 for HaIiPr.
Synthesis of Highly Substituted 1,2-Diazetidin-3-ones, Small-Ring Scaffolds for Drug Discovery
Santos, Marilia S.,Nortcliffe, Andrew,Lewis, William,Bradshaw, Tracey D.,Moody, Christopher J.
supporting information, p. 8325 - 8330 (2018/06/21)
1,2-Diazetidin-3-ones are readily accessible, small ring scaffolds that upon functionalization have the potential to produce diverse 3-dimensional structures for drug discovery. Thus, treatment of diazo hydrazides, obtained from simple hydrazides and malonyl half ester derivatives, followed by diazo transfer, with catalytic amounts of rhodium(II) acetate dimer results in intramolecular carbenoid N?H insertion to give 1,2-diazetidin-3-ones. Although subsequent functionalization reactions could be hampered by the lability of the 4-membered ring, a wide range of new derivatives was available by deprotection at N-1, and subsequent amide or urea formation. The structures of four four-membered rings was confirmed by X-ray crystallography; the compounds showed modest growth inhibitory activity in mammary carcinoma cells.
