- AMINOLYSIS OF MONOPHENYL SUCCINATES IN APROTIC SOLVENTS. PART I. CYCLIZATION OF MONOPHENYL SUCCINATES TO SUCCINIC ANHYDRIDE
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The reaction of benzylamine with monophenyl succinates in aprotic solvents has been shown to proceed simultaneously in two directions.A one-step (bimolecular) pathway involved internal and external catalysis, whereas a two-step pathway involved preliminary cyclization of the monoester to succinic anhydride followed by benzylaminolysis of the latter.In an effort to establish factors contributing to either of the two pathways of benzylaminolysis of the monoesters, a kinetic study of individual reactions has been undertaken.The cyclization of the monophenyl succinateswas studied in dioxane, benzene, N,N-dimethylformamide, pyridine and a pyridine-acetonitrile mixture.The rate of cyclization was proportional to the basicity and the electric permittivity of solvent, electron-accepting capacity of the substituent in the phenyl group of the monoester and inversely proportional to the initial concentration of the monoester.The mechanism of cyclization of the monoesters has been discussed.
- Bartnicka, H.,Smagowski, H.
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p. 1277 - 1286
(2007/10/02)
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- Photochemical Versus Aluminium Chloride-Catalyzed Fries Rearrangement of Aryl Hydrogen Succinates. Synthesis of 2(3H)-Furanones
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The photochemical and aluminium chloride-catalyzed Fries rearrangement of a series of aryl hydrogen succinates 3 a-f to the corresponding 4-oxoacids 1 a-f are compared.Both approaches are complementary: the photochemical process is more general and becomes the method of choice for the succinoylation of phenols supporting alkoxy or hydroxy substituents, while the classical rearrangement is superior in the presence of alkyl or halogen substituents.These results are applied to the preparation of the 2(3H)-furanones 2 a-f. - Keywords: Fries rearrangement; Photo-Fries rearrangement; Aryl hydrogen succinates; 4-Oxoacids; 2(3H)-Furanones.
- Fillol, Luis,Martinez-Utrilla, Roberto,Miranda, Miguel A.,Morera, Isabel M.
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p. 863 - 870
(2007/10/02)
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