77643-86-8Relevant articles and documents
Action de l'hydroxyuree sur les esters α-acetyleniques
Lassalvy, Christiane,Petrus, Clement,Petrus, Francoise
, p. 175 - 180 (2007/10/02)
Hydroxyurea, in its oxanion form NH2-CO-NHO(1-), reacts in basic medium by a 1,4-addition to α-acetylenic esters leading to the E and Z ethylenic β-ureidoxy esters isomers.The E isomer can be isolated and identified from reaction with ethyl tetrolate and ethyl propiolate.The Z isomer undergoes cyclisation in situ to give the 2-carboxamido-5-methyl-3-isoxazolone.With phenyl propiolate, the 3-hydroxy-5-phenyl isoxazole is directly obtained without isolation of the intermediate N-carboxamido derivative.In the case of ethyl propiolate two cyclic compounds are obtained: 3-hydroxyisoxazole and 2-N-carboxamido-5-ethoxy-3-isoxazolidinone.The formation of the former is due to the in situ cyclisation of the Z isomer.The isolation of the latter compound can be explained by solvent addition to the E β-ureidoxyacrylate intermadiate in a Michael addition followed by cyclisation.
