Phosphodiesterase 9 (PDE9) Inhibitors May Provide Effective Treatments for Neurodegenerative, Cardiovascular and Other Diseases.

The invention in this patent application relates to 4-oxo-4,5-dihydro-1H-pyrazolo-[3,4-d]-pyrimidine-3-carbonitrile derivatives represented herein by formula 1. These compounds are PDE9 inhibitors and may be useful as therapeutic agents for the treatment of cardiovascular and cerebrovascular diseases, such as hypertension, chronic kidney disease and heart failure, and neurological and psychiatric disorders, such as schizophrenia, psychosis or Huntington's disease, and those associated with striatal hypofunction or basal ganglia dysfunction.