Patent ID: 7049303

Claim:
A method of treating an RNA virus infection in a human or animal subject, the method comprising the step of administering to a subject infected with an RNA virus an effective amount of a ribonucleoside analogue of the formula I: where: X 1 =N or CH or CR 5 X 2 =N X 3 =NH 2 or O R 1 =H or alkyl or aryl or alkaryl or acyl R 2 =H or alkyl or aryl or alkaryl or acyl; R 3 =H or NR 5 R 6 or NR 5 NR 5 R 6 or NR 5 OR 5 R 5 =H or alkyl or alkenyl or alkynyl or aryl or alkaryl or acyl R 6 =H or alkyl or alkenyl or alkynyl or aryl or alkaryl or acyl and R 4 = wherein Z=O X 4 =OH R 7 =H or PO 3 2− or P 2 O 6 3− or P 3 O 9 4− or a masked phosphate derivative.