{HEAD ~ A method} of treating male erectile dysfunction comprising administering to a male human in need of such treatment {TAIL ~ an effective amount} of a compound of formula : ##STR6## wherein R1 is methyl or ethyl R2 is ethyl or n propyl 
{ HEAD ~ A method } of treating male erectile dysfunction comprising administering to a male human in need of such treatment { TAIL ~ an effective amount } of a compound of formula : # # STR6 # # wherein R1 is methyl or ethyl R2 is ethyl or n propyl
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH