100193-18-8Relevant articles and documents
5-hydroxyisoxalidin-3-ones and acetoacetyl hydroxamates derived from diketene and N-substituted hydroxylamines and their reactions with amines and hydrazines
Zelenin,Lagoda
, p. 1887 - 1899 (2007/10/03)
The direction of diketene reaction with N-substituted hydroxylamines depends on the nature of substituent on the nitrogen atom: With benzyl- and arylhydroxylamines, the reaction products are 5-hydroxy-5-methylisoxazolidin-3-ones, and with arylhydroxamic acids, acetoacetyl N-arylhydroxamates (N-acetoacetyl-oxybenzamides). In solutions, 5-hydroxy-5-methylisoxazolidin-3-ones are in tautomeric equilibrium with the N-hydroxyacetoacetamide form. Acetoacetyl hydroxamates are present exclusively in their linear form both in polar and in nonpolar media. The condensation products of the latter compounds with amines and hydrazines tend to ring-chain and/or prototropic tautomerism and configurational isomerism. The population of the tautomeric forms depends on the nature of the hydroxylamine component, the electronic properties of substituents in the amine and hydrazine components, and the nature of the solvent. Amino derivatives of N-hydroxyacetoacetamides are represented by the cyclic (5-aminoisoxazolidin-3-ones) and enamine forms; with hydrazino derivatives, the tautomeric mixture also includes the hydrazone forms as two configurational tautomers. Electron-acceptor substituents and nonpolar solvents shift the tautomeric equilibrium to the cyclic form. Amino and hydrazino derivatives of acetoacetyl hydroxamates are present exclusively in the enamine (enhydrazine) form as two geometric isomers.
