CRYSTAL FORM, PREPARATION METHOD, AND APPLICATION OF 4'-SUBSTITUTED NUCLEOSIDE

The invention discloses a crystal form, preparation and application of a 4'-substituted nucleoside compound I with the structure shown in the description, as well as salts, prodrugs and composition ofthe compound. An animal pharmacokinetic study result proves that effective drug concentrations of compounds Ia and Ig in HIV (human immunodeficiency virus) target cells and PBMC (peripheral blood monouclear cells) can still effectively inhibit HIV replication after 7 days and 5 days respectively. Therefore, the compound I can serve as a long-acting drug for preventing and treating AIDS (acquiredimmune deficiency syndrome). R is selected from acetenyl, azide and cyanogroup; X is selected from hydrogen and fluorine; B is selected from B1 and B2.