[swordlord]

i synthesized a urea-containing product from HDI diisocyanate and 3-amino pyridine, however i found it insoluble in almost every solvent i tried, from DMSO to cyclohexane, almost everything in my lab, even at temperature high to 80 degree C. 
i really have no idea what i should do next, so you guys any suggestion?

[ace]

What is the compound you produced?   Is this perhaps a lactam?

[agrobert]

What solvents/solvent systems have you tried so we can make suggestions?  Is it possible for you to draw  which product(s) you think you may have formed?  If you have a mixture of products you may be dissolving some and not others.  (This can be used to your advantage)  I know most ureas are not soluble in polar solvents.

[swordlord]

What solvents/solvent systems have you tried so we can make suggestions?  Is it possible for you to draw  which product(s) you think you may have formed?  If you have a mixture of products you may be dissolving some and not others.  (This can be used to your advantage)  I know most ureas are not soluble in polar solvents.

the structure of my product is illustated in the attached pic, confirmed by NMR result.
i've tried almost every single solvent, such as water, methanol, ethanol, acetonitrile, CHCl3, DMSO, hexane, cyclohexane...none of which dissolves my product. i guess mabe some mixed solvents may do, which however i don't know how to choose and the ratios should be.

[agrobert]

ethyl acetate, THF, acetone, toluene?
labrosol, tween, tween/ethanol, PEG, PVP, pyrrolidone?

Depends why you need to dissolve this sample? Subsequent reaction, NMR, drug delivery?