[daveyboy]

Can someone please tell me of a substance that is very hard to manufacture requiring great knowledge of chemistry (preferably organic chemistry) yet is not controlled, has no illegal uses and hopefully also has some very interesting properties.

Being able to sell it is an interesting property of course.
Having interesting property is the least important of these.

I want to know a substance that if I can make it safely and in a pure state then I have achieved a high level of chemical expertise. The non illegal stuff is so I can do it in plain view without having to faff about with fake ID and so if the police get interested they can come and have a look and I will be more than happy to show them all about it

Please if you can think up that that I would need to understand well as many aspects of chemistry as possible.

Then I will read up on just how you make it and work backwards until I know how to do it

[DemonicAcid]

Palytoxin.

[408]

bis(triaminoguanidinium) azotetrazolate

Your only carbon-containing precursor can be cyanuric acid.  You can use any common acid/bases/reagents. 

You will learn:  Dehydration and diazotization reactions, simple inorganic salt chemistry,high temperature solid state reactions, cyclization reactions, reactions in molten salts, azo chemistry and more!

You get a cookie if you do it with household products, which is possible.

[daveyboy]

Thanks guys, I'm very broke right now so the learning chem thing is going to take a whole while but hopefully I fix the money flow soon then I can get cracking.