Caffeine Analogs

[Jason Kennerly]

Can anyone provide any information on caffeine analogs with stimulant 
properties? It seems most caffeine analogs that I notice in literature 
have other things in mind - vasodilator / smooth muscle relaxer / etc 
type properties are exaggerated while the stimulant activity is reduced.

Specifically there are two things I am wondering about. What data is 
available on the antidepressant ELIDIN / DIMETHAZAN 
[1,3-dimethyl,7-(2-dimethylaminoethyl)xanthine]

and what information is available on ETHYL homologs of caffeine 
(ethyl-theophylline, ethyl-theobromine, triethylxanthine, etc)