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Selective deprotection of phenacyl, benzyl and methyl esters of N-protected amino acids and dipeptides and N-protected amino acids benzyl ester linked to resins with bis(tributyltin) oxide

Article

Authorship
Salomon, Claudio J. ; MATA, ERNESTO GABINO ; Mascaretti, Oreste A.
Date
1996
Publishing House and Editing Place
Royal Society of Chemistry
Magazine
JOURNAL CHEMICAL SOCIETY PERKIN Royal Society of Chemistry
Summary Information provided by the agent in SIGEVA
Phenacyl, methyl and benzyl esters of variousN-α-Boc, N-α-Cbz or N,N-dimethylamino protected amino acids and dipeptides, as well as esters of N-α-protected amino acids linked to Wang and Pam resins have been efficiently and chemoselectively cleaved by bis(tributyltin) oxide in aprotic solvents to give the corresponding carboxylic acids in good yields. Moreover, the absence of racemization during the deprotection has been demonstrated. A limitation of the method is the instabil... Phenacyl, methyl and benzyl esters of variousN-α-Boc, N-α-Cbz or N,N-dimethylamino protected amino acids and dipeptides, as well as esters of N-α-protected amino acids linked to Wang and Pam resins have been efficiently and chemoselectively cleaved by bis(tributyltin) oxide in aprotic solvents to give the corresponding carboxylic acids in good yields. Moreover, the absence of racemization during the deprotection has been demonstrated. A limitation of the method is the instability of the N-ε-Fmoc group in the amino acid esters 8 and 10, N-α-Fmoc-L-alanine linked to Wang resin 23 and the Cbz protecting groups in N-α-Boc-N-ε-Cbz-L-lysine benzyl and methyl esters (5 and 7), respectively, and N-α-Cbz-L-alanyl-L-alanine methyl ester 19. In the case of N-α-protected dipeptides, there was no evidence of free amino acid which indicates that the peptide bond is unaffected.
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Key Words
solid-phase peptide synthesisbis(tributyltin) oxide