An approach for clarification of the mechanism of inactivation of ribonucleotide reductases with 3'<¹⁷O>-labeled 2'-azido-2'-deoxynucleotides

Authors

Saiful Mahmud Chowdhury, Florida International University

Document Type

Thesis

Degree

Master of Science (MS)

Major/Program

Chemistry

First Advisor's Name

Stanislaw F. Wnuk

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Leonard Keller

Third Advisor's Name

Kevin O'Shea

Date of Defense

1-15-2001

Abstract

Inactivation of ribonucleotide reductases by 2'-azido-2'-deoxynucleotides is accompanied by appearance of new EPR signals for a nitrogen-centered radical. The structure of this elusive nitrogen-centered radical has been studied extensively and shown to be derived from azide moiety. Synthesis of 3'[¹⁷ O]-labeled 2'-azido-2'-deoxyuridine-5'- diphosphate was targeted in this research. Such a labeled analogue should perturb the EPR spectrum in predictable fashion, and the hyperfine interaction between the free electron and the ¹⁷O nucleus should allow the choice between the recently proposed structures of this elusive radical (Van Der Donk, W. A. et al. J Am. Chem. Soc. 1995, 117, 8908-8916).

The labeled 2'-azido-2'-deoxynucleotides was prepared by thermolysis of O²,3'- anhydrouridine to give the more stable O²,2'-anhydrouridine derivatives with concomitant rearrangement of the 2'-O-benzoyl[¹⁷O] group into the 3'-[¹⁷O]-benzoyl intermediate. Deprotection and ring opening with LiF/Me₃SiN₃ gave the 3'[¹⁷O]-2--azido 2'-deoxyuridine. Tosylation (O5') and displacement of the 5'-tosylate by treatment with tris(tetra-n-butylarmonium) hydrogen pyrophosphate gave 3'[¹⁷O]-2'-azido-2'- deoxyuridine 5'-diphosphate. All the intermediates and the products were characterized by ¹H-NMR, ¹³C-NMR, ^3IP-NMR and isotopic enhancement was confirmed by using mass spectrometry.

Identifier

FI14060821

Comments

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Recommended Citation

Chowdhury, Saiful Mahmud, "An approach for clarification of the mechanism of inactivation of ribonucleotide reductases with 3'<¹⁷O>-labeled 2'-azido-2'-deoxynucleotides" (2001). FIU Electronic Theses and Dissertations. 2350.
https://digitalcommons.fiu.edu/etd/2350