Why didn't the Chinese scientists publish the first qinghaosu report in a Western journal?
Well, Western journals aren't the be all and end all, but I think the reason here must be that to publish in a foreign journal in the 1970s would have been viewed as treason. Anyone who did it would have been labeled a capitalist-roader or some such and dealt with very harshly.
So it wasn't until March 1982 that Tu Youyou 屠呦呦 published a report on the discovery in a foreign (German) journal, Planta Medica.
Now, of course, there's no such reticence and Chinese scientists are positively encouraged to publish in high-impact foreign journals. Shows how times have changed.