ormula XIX with an alkoxide in a suitable solvent, e.g., potassium ethoxide in N,N-dimethylformamide, at ambient conditions. [0174] In step (5) of Reaction Scheme II a compound of Formula XX is chlorinated using a suitable chlorinating agent such as thionyl chloride, oxalyl chloride, phosphorus pentachloride or preferably phosphorus oxychloride to provide a 5-chlorotetrazolo[1,5-a][1,7]naphthyridi