7-Deaza-2,8-diazaadenine containing oligonucleotides: synthesis, ring opening and base pairing of 7-halogenated nucleosides
نویسندگان
چکیده
Oligonucleotides containing 7-bromo-7-deaza-2,8-diaza-2 0-deoxyadenosine (3) and 5-amino-3-bromo-4-carbamoyl-1-(2 0deoxy-b-D-erythro-pentofuranosyl)pyrazole (4) were synthesized. Compound 3 was prepared from 7-bromo-8-aza-7-deaza-2 0-deoxyadenosine (5) via the 1,N-etheno derivative 6 and was converted into the phosphoramidite 11. The 7-bromo substituent of 3 increases oligonucleotide duplex stability compared to the non-halogenated nucleoside. Oligonucleotides incorporating 3 are transformed to those containing 4 during long time deprotection at elevated temperature (25% aq ammonia, 60 8C, 30 h). Compound 3 forms a strong base pair with dG. The base pair stability decreases in the order dGOdTOdAOdC. Similar recognition selectivity is observed for the pyrazole nucleoside 4, however, due to decreased stacking and higher flexibility of the pyrazole moiety, duplexes are less stable than those containing 3. q 2005 Elsevier Ltd. All rights reserved.
منابع مشابه
Pyrazolo[3,4-d][1,2,3]triazine DNA: synthesis and base pairing of 7-deaza-2,8-diaza-2'-deoxyadenosine.
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