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Concerning selectivity in the oxidation of peptides by dioxiranes. Further insight into the effect of carbamate protecting groups.

ABSTRACT: With use of methyl(trifluoromethyl)dioxirane (TFDO), the oxidation of some tripeptide esters protected at the N-terminus with carbamate or amide groups could be achieved efficiently under mild conditions with no loss of configuration at the chiral centers. Expanding on preliminary investigations, it is found that, while peptides protected with amide groups (PG = Ac-, Tfa-, Piv-) undergo exclusive hydroxylation at the side chain, their analogues bearing a carbamate group (PG = Cbz-, Moc-, Boc-, TcBoc-) give competitive and/or concurrent hydroxylation at the terminal N-H moiety. Valuable nitro derivatives are also formed as a result of oxidative deprotection of the carbamate group with excess dioxirane. A rationale is proposed to explain the dependence of the selectivity upon the nature of the protecting group.

SUBMITTER: Annese C

PROVIDER: S-EPMC2922685 | biostudies-other | 2010 Jul

REPOSITORIES: biostudies-other

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Concerning selectivity in the oxidation of peptides by dioxiranes. Further insight into the effect of carbamate protecting groups.

Annese Cosimo C D'Accolti Lucia L De Zotti Marta M Fusco Caterina C Toniolo Claudio C Williard Paul G PG Curci Ruggero R

The Journal of organic chemistry 20100701 14

With use of methyl(trifluoromethyl)dioxirane (TFDO), the oxidation of some tripeptide esters protected at the N-terminus with carbamate or amide groups could be achieved efficiently under mild conditions with no loss of configuration at the chiral centers. Expanding on preliminary investigations, it is found that, while peptides protected with amide groups (PG = Ac-, Tfa-, Piv-) undergo exclusive hydroxylation at the side chain, their analogues bearing a carbamate group (PG = Cbz-, Moc-, Boc-, T ...[more]

PMID: 20560586

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