The present disclosure relates to p-toluene sulfonic acid salt of 5-amino-3-(2′-O-acetyl-3′-deoxy-beta-D-ribofuranosyl)-3H-thiazolo[4,5-d]pyrimidin-2-one and to its use in treating conditions such as viral infections, tumors, and cancer. Also disclosed is a method of preparing the p-toluene sulfonic acid salt of 5-amino-3-(2′-O-acetyl-3′-deoxy-β-D-ribofuranosyl)-3H-thiazolo[4,5-d]pyrimidin-2-one and methods for producing furanose compounds which are useful intermediates in the preparation of pharmaceutical compounds such as p-toluene sulfonic acid salt of 5-amino-3-(2′-O-acetyl-3′-deoxy-β-D-ribofuranosyl)-3H-thiazolo[4,5-d]pyrimidin-2-one and the like.