Annelation of a Pyrimidine Ring to an Existing Ring

Abstract

This chapter summarizes reactions that can annelate a pyrimidine ring onto an existing ring. The chapter also focuses on how to select the reactions that can introduce a desired group into the pyrimidine ring. The reactions of rings with an endocyclic keto group adjacent to a replaceable hydrogen atom are also discussed. These reactions require a reagent with a positively charged carbon atom that is capable of an electrophilic attack on the carbanion formed by the loss of a proton from the alpha position of the ketone. The reactions of rings with an endocyclic to the group adjacent to an exocyclic ester, ketone, or methide (alkylidene) substituent from lactones or lactams are discussed. The chapter describes a miscellaneous set of reactions all of which require a parent nucleus that is aromatic, π -excessive, and electronically equipped to support an electrophilic attack adjacent to the amino group. Common substituents found in the product are alkyl, aryl, amino, and oxo groups. The rings with an amino group adjacent to an aminomethyl, chloromethyl, or hydroxymethyl group are also discussed in the chapter.