Compounds having a structure according to formula (I) or (II)

##STR00001##

where R.sup.1, R.sup.2, R.sup.3, R.sup.4, Ar and X.sup.1 are as defined herein, are agonists for the Toll-like receptor 7 (TLR7) and can be used as adjuvants for stimulating the immune system. Some such compounds can be used in conjugates for targeted delivery to the organ or tissue of intended action.

Compounds having a structure according to formula (I) or (II)

##STR00001##

where R.sup.1, R.sup.2, R.sup.3, R.sup.4, Ar and X.sup.1 are as defined herein, are agonists for the Toll-like receptor 7 (TLR7) and can be used as adjuvants for stimulating the immune system. Some such compounds can be used in conjugates for targeted delivery to the organ or tissue of intended action.

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 an improved process for the preparation of Valacyclovir or pharmaceutically acceptable salts thereof, which comprises reaction of amine-protected Valacyclovir or its salt with deprotecting agent in a continuous flow reactor.

The present invention relates to an improved process for the preparation of Valacyclovir or pharmaceutically acceptable salts thereof, which comprises reaction of amine-protected Valacyclovir or its salt with deprotecting agent in a continuous flow reactor.

Disclosed is a liver specific delivery (LSD)-based entecavir antiviral prodrug, i.e., a nucleoside cyclic phosphate compound, and the application thereof. Specifically, disclosed are a compound as represented by formula (I) and isomers, pharmaceutically acceptable salts, hydrates, and solvates of the compound, and a corresponding pharmaceutical composition. Also disclosed is the application of the compound of the present invention, used separately or used in combination with other antiviral drugs, against viruses, especially the application against hepatitis B virus (HBV).

##STR00001##

Compounds having a structure according to formula (I) or (II)

##STR00001##

where R.sup.1, R.sup.2, and Ar are as defined herein, are agonists for the Toll-like receptor 7 (TLR7) and can be used as adjuvants for stimulating the immune system. Some such compounds can be used in conjugates for targeted delivery to the organ or tissue of intended action.

Compounds having a structure according to formula (I) or (II)

##STR00001##

where R.sup.1, R.sup.2, and Ar are as defined herein, are agonists for the Toll-like receptor 7 (TLR7) and can be used as adjuvants for stimulating the immune system. Some such compounds can be used in conjugates for targeted delivery to the organ or tissue of intended action.

The present invention relates to -PNA monomers according to Formula I where substituent groups R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, B and P are defined as set forth in the specification. The invention also provides methodology for synthesizing compounds according to Formula I and methodology for synthesizing PNA oligomers that incorporate one or more Formula I monomers.