Scheme 1.
Synthetic pathway for compounds 3a–e
Reagents and conditions: (i) NaOCH3, CH3OH, room temp. 3 h; (ii) dimethyloxalate, CH3OH, reflux, 4 h; (iii) hydrazine hydrate, EtOH, reflux 3 h.
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.