RESEARCH ARTICLE

 

Synthesis and NMR elucidation of novel pentacycloundecane-derived peptides

 

 

Rajshekhar Karpoormath^I; Oluseye K. Onajole^I; Tricia Naicker^II; Thavendran Govender^II; Glenn E.M. Maguire^I; Hendrik G. Kruger^{I, *}

^ISchool of Chemistry, University of KwaZulu-Natal, Durban, 4001, South Africa
^IISchool of Pharmacy and Pharmacology, University of KwaZulu-Natal, Durban, 4001, South Africa

 

 

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ABSTRACT

Herein we report the synthesis and NMR elucidation of five novel pentacycloundecane (PCU)-derived short peptides as potential HIV protease inhibitors. ¹H and ¹³C spectral analysis show major overlapping of methine resonance of the PCU 'cage' thereby making it extremely difficult to assign the NMR signals. Attachment of short peptides to the cage at position C-8/C-11 results in conformational differences of the peptide side chains due to diastereomeric interactions between the cage skeleton and the chiral side chains. The use of two-dimensional NMR techniques proved to be highly effective in the elucidation of such systems.

Keywords: ¹H NMR, ¹³C NMR, 2D NMR, PCU diol diaminoacid, HIV protease inhibitors

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Full text available only in PDF format.

 

Acknowledgements

This research was supported by NRF (SA) TG (GUN: 66319), HGK (GUN: 69728), HGK and PIA (SA-Sweden bilateral grant), Aspen Pharmacare and University of KwaZulu-Natal for financial support. The authors thank Dr Katja Petzold for assistance with the EASY-ROESY experiments. We also thank Mr. Dilip Jagjivan (UKZN, South Africa) for assistance with NMR experiments.

 

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Received 14 December 2012
Revised 24 January 2012
Accepted 10 February 2012

 

 

* To whom correspondence should be addressed. E-mail: kruger@ukzn.ac.za