Scheme 1.
Synthesis of new coumarin derivatives containing 1,2,4-triazole (3–6), 4,5-dicyanoimidazole (7) and purine (8–13) moiety, their open ring analogues (14–17) as well as acyclic nucleoside analogue (18).
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.