In this work we present the results obtained for the N-alkylation of a series of N-arylsulfonyl-alpha-amino acid methyl esters bearing different substituents at the 4-position of the sulfonamide aromatic ring. In particular, we compare the reactivity of these species with diazomethane and trimethyloxonium tetrafluoroborate in N-methylation processes. Diazomethylation is unsuccessful for N-arylsulfonamide derivatives containing electron-releasing groups on the aromatic ring. In these cases trimethyloxonium tetrafluoroborate is the reagent of choice for the direct and quantitative N-methylation. Further we extend our evaluation to the use of triethyloxonium tetrafluoroborate. This reagent shows to be very efficient in order to prepare N-ethyl derivatives of N-arylsulfonyl-alpha-amino acid methyl esters. An experimental protocol similar to that used for N-methylation with trimethyloxonium tetrafluoroborate is applied for the N-ethylation.
N-alkylation of N-aryl-alpha-amino acid methyl esters by trialkyloxonium tetrafluoroborates / DE MARCO, R; DI GIOIA M., L; Liguori, Angelo; Perri, F; Siciliano, Carlo; Spinella, M.. - In: TETRAHEDRON. - ISSN 0040-4020. - 67:50(2011), pp. 9708-9714.
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Titolo: | N-alkylation of N-aryl-alpha-amino acid methyl esters by trialkyloxonium tetrafluoroborates |
Autori: | |
Data di pubblicazione: | 2011 |
Rivista: | |
Citazione: | N-alkylation of N-aryl-alpha-amino acid methyl esters by trialkyloxonium tetrafluoroborates / DE MARCO, R; DI GIOIA M., L; Liguori, Angelo; Perri, F; Siciliano, Carlo; Spinella, M.. - In: TETRAHEDRON. - ISSN 0040-4020. - 67:50(2011), pp. 9708-9714. |
Handle: | http://hdl.handle.net/20.500.11770/155869 |
Appare nelle tipologie: | 1.1 Articolo in rivista |