Selective deprotection nucleopeptides

PGA-mediated selective deprotection of the phenylacetyl-protected nucleobase has been implemented successfully in the synthesis of nucleopeptides (Scheme... 

Scheme 17 Selective Deprotection of the C-Terminus of a Nucleopeptide Methyl Ester by Papainb l...

Figure 30 Selective deprotection of different functionalities of nucleopeptides by various enzymes.

Proteases, such as thermitase,papain,f " l and subtilisinf have been employed for the deprotection of tert-butyl and methyl esters from various glycopeptides. More interestingly, the C-terminus of a nucleopeptide methyl ester 8 was deprotected selectively and in very high yield by papain.l Neither the acetate, the N-terminal urethane, the allyl phosphate, nor the phenylacetamide protection of the nucleobase were attacked (Scheme 17). 

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