NEW MATERIAL:A compound shown by formula I (R1 is amino or OH; R2 is H, halogen or alkyl when R1 is amino and R2 is alkyl when R1 is OH) or a salt thereof.

EXAMPLE: 3'-Deoxyarabinofuranosylthymine.

USE: An antiviral agent and anti-retroviral agent.

PREPARATION: A protecting group is introduced to the 5-position of a compound shown by formula II, an eliminable group is introduced to the 2'-position and when R1 of basic part is amino group, a protecting group is introduced to the amino group. The compound shown by formula II is treated with an alkali to give a compound shown by formula III. Then 2-2' bond of the compound is hydrolyzed and the compound is deprotected.