Disclosed herein are nucleosides and nucleotides analogs, methods for preparing the same, and methods for treating and/or ameliorating infection caused by a Coronaviridae virus, a Caliciviridae virus, an Orthomyxoviridae virus, a Herpesviridae virus, a Flaviviridae virus, a Filoviridae virus, and a Pneumoviridae virus with one or more nucleoside and nucleotide analogs of formula I. In certain embodiments, compounds and compositions of nucleoside or nucleotide derivatives are disclosed, which can be administered either alone or in combination with other anti-viral agents. In certain embodiments, the compounds are according to Formula (I): or a pharmaceutically acceptable salt, solvate, stereoisomeric form, tautomeric form or polymorphic form thereof, wherein R1, R2, R3, R4, X, and sugar are as described herein.