| abstract |
The object of the present invention is to provide a nucleoside or a nucleotide, or a derivative thereof, which has an unnatural base. The nucleoside and others of the present invention are characterized by having a 2-amino-6-(2-thiazolyl)purin-9-yl group or a 2-amino-6-(2-oxazolyl)purin-9-yl group as a base, wherein the 4- and/or 5-position of the thiazolyl or oxazolyl group may be substituted. |