La réactivité du groupement carbonyle et l'activité déshydrogénasique des composés de la série de l'isatine. II. (Note préliminaire)

Abstract

On a mesuré l'activité déshydrogénasique d'un nombre considérable de dérivés mono‐ et disubstitués de l'isatine, dont une partie sont nouveaux.

N-Acyl-3,3-difluoro-2-oxoindoles as versatile intermediates for the preparation of different 2,2-difluorophenylacetic derivatives

“…[9][10][11] The isatins were either commercially available or were synthesized. 12 Boechat et al Vol. 19, No.…”

“…In this work we have reacted compounds 1-6 towards DAST, a specific reagent for conversion of aldehyde and ketone to gem-difluoro compounds (7)(8)(9)(10)(11)(12). 8 We have also investigated the enhanced electrophilicity of the C 2 carbonyl group resulting from the introduction of the two fluorine atoms at C-3 and from acylation of N-1, which facilitate the attack of a second nucleophile at the C 2 carbonyl, leading to the formation of (13-46) on opening of the heterocyclic ring.…”

“…8 We have also investigated the enhanced electrophilicity of the C 2 carbonyl group resulting from the introduction of the two fluorine atoms at C-3 and from acylation of N-1, which facilitate the attack of a second nucleophile at the C 2 carbonyl, leading to the formation of (13-46) on opening of the heterocyclic ring. (1)(2)(3)(4)(5)(6) to give N-acyl-3,3-difluoro-2-oxoindoles (7)(8)(9)(10)(11)(12) N-acylisatins were obtained by N-acetylation (1-4), Nchloroacetylation (5) and N-benzoylation (6) of the appropriate isatins by methods described in the literature. [9][10][11] The isatins were either commercially available or were synthesized.…”

“…[15][16][17] We, however, have found that our fluorinated derivatives (7)(8)(9)(10)(11)(12) were readily hydrolyzed and solvolyzed at room temperature confirming the enhanced eletrophilicity of C 2 and thereby allowing an easy opening of the heterocyclic ring. Difluoroacids (13)(14)(15)(16) were produced in water, difluoroesters (17)(18)(19)(20), in alcohols and difluoroamides (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) in amines.…”

“…5 In this paper we have used N-acylisatins (1-6) as precursors of N-acyl-3,3-difluoro-2-oxoindoles (7)(8)(9)(10)(11)(12) via fluorination reactions with diethylaminosulphur trifluoride (DAST). N-acyl-3,3-difluoro-2-oxoindoles (7)(8)(9)(10)(11)(12) have been shown to be versatile intermediates which, on reaction with nucleophiles, lead to the formation of a variety of heterocyclic ring opened products.…”