5331-73-7Relevant articles and documents
EFFET DE SOLVANT SUR SUPPORT SOLIDE: COMPARAISON DE POLYMERES PORTEURS DE MOTIFS HEXAMETHYLPHOSPHOROTRIAMIDE, N-PYRROLIDONE ET N-OXAZOLIDINONE SUR L'ALKYLATION DE L'ENOLATE DE L'ACETYLACETATE D'ETHYLE
Nee, Gerard,Seyden-Penne, Jacqueline
, p. 3485 - 3488 (1982)
The rate of ethylation by Et2SO4 of potassium enolate of ethylacetoacetate is enhanced in the presence of polymers bearing N-pyrrolidone (P-N.P.) or N-oxazolidone (P-N.O.) moieties.It depends inter alia on the nature of the polymeric skeleton.The C/O alkylation as well as the ratio E/Z of the enol ethers gives an account of the interaction of the enolate with its associated cation inside the polymer: the efficiency is thus: P-HMPA > P-N.P. > P-N.O., although a different order is observed on the reaction rate: P-HMPA > P-N.O. > P-N.P..Thus, this test reaction gives more information on the different interactions involved than the study of rate enhancements of nucleophilic substitutions.
INFLUENCE DE LA SOLVATATION PAR LE TERT-BUTANOL SUR LA STRUCTURE ET LA REACTIVE DE L'ENOLATE DE POTASSIUM DE L'ACETYLACETATE D'ETHYLE EN PRESENCE DE COURONNE OU DE CRYPTAND. ETUDE PAR SPECTROMETRIE INFRA-ROUGE ET CINETIQE.
Sarthou, P.,Bram, G.,Guibe, F.,Corset, J.
, p. 1043 - 1050 (2007/10/02)
The structure and the nucleophilic reactivity of crowned (18-crown-6) or crypted potassium ethyl acetoacetate enolate have been compared in tert-butanol and in DME (or THF).In the protic solvent tert-butanol, the crowned and the cryptated potassium enolate species both exist as loose ion pairs in which the enolate anion, strongly hidrogen-bonded to the solvent, is in a "transoid" (non chelating) conformation.Both species show similar reactivities towards alkylating agents but completely different reactivities are observed in aprotic weakly dissociating media (THF, DME).In contrast to what is observed in tert-bu tanol, the cryptated species and the crowned species have very different nucleophilic reactivities in THF or DME: in those solvents only the cryptated species retains a loose ion pair structure; the crowned species is a contact ion pair in which the enolate anion chelates the potassium cation.The solvatation of this crowned chelate species by tert-butanol has been demonstrated in binary mixtures of solvents (C6D6-t-BuOH, THF-t-BuOH).The oxygen basicity of the enolate anion is very different in the crowned chelated ion pair compared with the cryptand separated ion pair.
