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