| 摘要 |
PURPOSE:To obtain derivative, having a low possibility for impairing the function essential to nucleic acid and important for synthesizing a modified DNA in which an optional number of thiol linkers are transduced into optional positions of an oligomer. CONSTITUTION:This nucleoside derivative is expressed by formula I [B is purine or pyrimidine; R1 is H, etc.; either of R2 and R3 is H and the other is (CH2)nR4; (n) is an integer of >=3; R4 is thiol which may have a protecting group or a nonradioactive label]. The derivative expressed by formula I is obtained by reacting a derivative, prepared from a ribonucleoside and expressed by formula II (R5 is protecting group of hydroxyl group; B is purine or pyrimidine, preferably adenine, guanine, cytosine or uracil) with a base such as a metallic hydride in an organic solvent such as tetrahydrofuran, adding a compound expressed by the formula X(CH2)nX (X is halogen, preferably Br) and adding N,N- dimethylformamide to the resultant alkoxide, thermally refluxing the obtained mixture for several hr to several days, isolating and purifying the prepared product of formula III and reacting the isolated and purified product with a thiol, a thiocarboxylic acid, etc. |
