Synthesis of 2-N-tert-Butylaminoxylpurines and EPR Studies of Oligonucleotides Bearing Them

Abstract

We designed spin-labeled nucleosides in which a spin source is directly attached to nucleobase and synthesized 2-N-tert-butylaminoxylinosine(1a), 2-N-tert-butylaminoxyladenosine(2a) and oligodeoxynucleotides (ODNs) bearing them. Lithiation at the 2-position of 8-TIPS-6-chloropurine derivatives and the following reaction with 2-methyl-2-nitrosopropane afforded 2-N-tert-butylhydroxylamino-6-chloropurine, which was converted to 1a and 2a. The ODN bearing 1a and 2a were also synthesized successfully and EPR studies were carried out. Spectra of single strand showed broad three lines in phosphate buffer. Upon duplex formation, the upfield line disappeared completely at 0 °C and EPR spectra of single strand and duplex were distinguishable visually. Detailed analysis of spectra is in progress.

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