| abstract |
The invention compounds and the compounds each of formula (IV) of formula (3) - if R includes reacting in the presence, at this time, the OR to produce the compound of formula 1 CH 2 CH 3, and preparing the compounds of formula 2 If desired, the present invention relates to a compound of formula 1 (sildenafil / viagra), which is CH 2 CH 2 CH 3 , and a process for preparing a compound of formula 2:n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n Wherein X is a leaving group. |