Synthesis of Potential Impurities of Valacyclovir Hydrochloride: An Anti-Retroviral Drug

Valacyclovir is an antiviral drug useful for the treatment of outbreaks of herpes simplex or herpes zoster (shingles). It is also useful to avoid cytomegalovirus following a kidney transplant in high-risk cases. Simple synthetic protocols toward the synthesis of two potential impurities, namely, European Pharmacopeia impurity N (2) and European Pharmacopeia impurity P (3) of valacyclovir hydrochloride (1) are reported from commercially accessible inexpensive raw materials. This work is predominantly useful for obtaining pure valacyclovir.