{HEAD ~ A method} of treating {TAIL ~ male erectile dysfunction} comprising administering to a male human a pyrimidine compound of formula I 
of treating
{ HEAD ~ A method } of treating { TAIL ~ male erectile dysfunction } comprising administering to a male human a pyrimidine compound of formula I
HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH