Studies on the synthesis of cyanomethyleneamino pseudopeptides
| Autor: | S. Vinuesa, Rosario Herranz, M. Teresa García-López, M.Luisa Suárez-Gea |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | The Journal of Organic Chemistry. 58:5186-5191 |
| ISSN: | 1520-6904 0022-3263 |
| Popis: | Various cyanomethyleneamino pseudodipeptides were easily prepared in high yield by the Lewis acid catalyzed addition of trimethylsilyl cyanide to unstable aldimine intermediates, obtained from the reaction of N-protected α-amino aldehydes with C-protected amino acids. The two possible (R)- and (S)-epimers at the peptide bond surrogate chiral center were obtained. In this thermodynamically controlled synthesis, the absolute configurations of the α-amino aldehyde and the amino acid proved to be the main factors determining its stereoselectivity. The new N-Boc- and N-Z-protected pseudodipeptides were deblocked under standard conditions. In spite of the lability of the new peptide bond surrogate ψ[CH(CN)NH] in basic medium, high yields of C-deprotected pseudodipeptides were obtained by controlling the saponification conditions of the methyl esters. The use of free α-amino acids in the modified Srecker synthesis reported here can be employed as an alternative for the synthesis of C-deprotected cyanomethyleneamino pseudopeptides. The N- or C-elongation of these pseudodipeptides via the DCC method led to the corresponding ψ[CH(CN)NH] pseudotripeptides in high yields |
| Databáze: | OpenAIRE |
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