Provided herein are compounds, compositions and methods for the treatment of Flaviviridae infections, including HCV infections. In certain embodiments, compounds and compositions of nucleoside derivatives are disclosed, which can be administered either alone or in combination with other anti-viral agents. In certain embodiments, the compounds are 2,4-bridged nucleosides which display remarkable efficacy and bioavailability for the treatment of, for example, HCV infection in a human. In certain embodiments, the 2,4-bridged nucleosides are of Formula 3001: ##STR00001##
or a pharmaceutically acceptable salt, solvate, stereoisomeric form, tautomeric form or polymorphic form thereof, where PD, B, W, X, R.sup.A, R.sup.B, R.sup.C and R.sup.D are as described herein.

Provided herein are compounds, compositions and methods for the treatment of Flaviviridae infections, including HCV infections. In certain embodiments, compounds and compositions of nucleoside derivatives are disclosed, which can be administered either alone or in combination with other anti-viral agents. In certain embodiments, the compounds are 2,4-bridged nucleosides which display remarkable efficacy and bioavailability for the treatment of, for example, HCV infection in a human. In certain embodiments, the 2,4-bridged nucleosides are of Formula 3001: ##STR00001##
or a pharmaceutically acceptable salt, solvate, stereoisomeric form, tautomeric form or polymorphic form thereof, where PD, B, W, X, R.sup.A, R.sup.B, R.sup.C and R.sup.D are as described herein.

To provide a chiral reagent or a salt thereof. The chiral reagent has following chemical formula (I). In the formula (I), G.sup.1 and G.sup.2 are independently a hydrogen atom, a nitro group (NO.sub.2), a halogen atom, a cyano group (CN), a group of formula (II) or (III), or both G.sup.1 and G.sup.2 taken together to form a group of formula (IV). ##STR00001##

To provide a chiral reagent or a salt thereof. The chiral reagent has following chemical formula (I). In the formula (I), G.sup.1 and G.sup.2 are independently a hydrogen atom, a nitro group (NO.sub.2), a halogen atom, a cyano group (CN), a group of formula (II) or (III), or both G.sup.1 and G.sup.2 taken together to form a group of formula (IV). ##STR00001##

The present invention relates to Cyclic Phosphate Substituted Nucleoside Derivatives of Formula (I), and pharmaceutically acceptable salts thereof, wherein A, B, Q, V, R.sup.1, R.sup.2 and R.sup.3 are as defined herein. The present invention also relates to compositions comprising a Cyclic Phosphate Substituted Nucleoside Derivative, and methods of using the Cyclic Phosphate Substituted Nucleoside Derivatives for treating or preventing HCV infection in a patient.

##STR00001##

Disclosed are P-stereogenic groups that may be used in the synthesis of compounds including stereochemically enriched P-stereogenic phosphorothioates. P-stereogenic groups may be provided in nucleoside phosphoramidites including a sugar bonded to a nucleobase and to a stereochemically enriched phosphoramidite as well as methods of their use and methods of making them.

Disclosed are P-stereogenic groups that may be used in the synthesis of compounds including stereochemically enriched P-stereogenic phosphorothioates. P-stereogenic groups may be provided in nucleoside phosphoramidites including a sugar bonded to a nucleobase and to a stereochemically enriched phosphoramidite as well as methods of their use and methods of making them.

The present invention relates to compounds of the formula I:

##STR00001##

including any possible stereoisomers thereof, wherein R.sup.9 has the meaning as defined herein, or a pharmaceutically acceptable salt or solvate thereof

The present invention also relates to processes for preparing said compounds, pharmaceutical compositions containing them and their use, alone or in combination with other HCV inhibitors, in HCV therapy.

The present invention relates to compounds of the formula I:

##STR00001##

including any possible stereoisomers thereof, wherein R.sup.9 has the meaning as defined herein, or a pharmaceutically acceptable salt or solvate thereof

The present invention also relates to processes for preparing said compounds, pharmaceutical compositions containing them and their use, alone or in combination with other HCV inhibitors, in HCV therapy.

Disclosed herein are a liver specific delivery (LSD)-based antiviral prodrug nucleoside cyclophosphate compound and uses thereof. Specifically, this application provides a compound of formula (I), or an isomer, a pharmaceutically acceptable salt, a hydrate, a solvate or a pharmaceutical composition thereof. This application also provides an application of the compound alone or in combination with other antiviral drugs in the treatment for viruses, particularly hepatitis C virus (HCV).

##STR00001##