Synthesis of <i>N</i>-Oxyureas by Substitution and Cope-Type Hydroamination Reactions Using <i>O</i>-Isocyanate Precursors
作者:Meredith A. Allen、Ryan A. Ivanovich、Dilan E. Polat、André M. Beauchemin
DOI:10.1021/acs.orglett.7b03288
日期:2017.12.15
Oxy-carbamate O-isocyanate precursors facilitate access to synthetically valuable N-oxyureas via substitution with amines. This work exploits the reactivity of suitable O-isocyanate precursors, identified by a thorough study highlighting the different reactivity of isocyanate masking groups. This led to bench-stable O-isocyanate precursors, offering improved versatility in the synthesis of N-oxyureas, and
An easy access to unsymmetrical ureas: a photocatalytic approach to the Lossen rearrangement
作者:Arvind K. Yadav、Vishnu P. Srivastava、Lal Dhar S. Yadav
DOI:10.1039/c4ra03805c
日期:——
synthesis of unsymmetrical ureas from various hydroxamic acids and amines has been developed. Plausibly, the protocol involves visible-light-initiated in situ formation of Vilsmeier–Haack reagent and COBr2 with CBr4 and a catalytic amount of DMF in the presence of Ru(bpy)3Cl2 as a photocatalyst to bring about the Lossenrearrangement at room temperature.
The present invention relates to new 4-carbamoyloxy-oxazaphosphorins of the general Formula I ##STR1## as well as to a method for the treatment of malign tumor diseases in humans using such compounds as active agent.
Formation of Complex Hydrazine Derivatives via Aza-Lossen Rearrangement
作者:Dilan E. Polat、David D. Brzezinski、André M. Beauchemin
DOI:10.1021/acs.orglett.9b01742
日期:2019.6.21
The development of a broadly applicable procedure for the aza-Lossen rearrangement is reported. This process converts amines into complexhydrazinederivatives in two steps under safe, mild conditions. This method allows the chemoselective formation of N–N bonds, resulting in the synthesis of cyclic and acyclic products while avoiding side reactions of the amphoteric (ambident) nitrogen-substituted
We report herein a strategy to afford a multicomponent catalyticenantioselectivesynthesis of β-substituted isoxazolidin-5-ones via a KMC process promoted by a suited cupreine used as bifunctional organocatalyst. The hydroxamic acid component, with a sterically hindered amide moiety, proved to be key for the successful formation and transformation of the obtained original N-amide isoxazolidin-5-ones