caffeine

I've had too much nasty office coffee and not enough sleep. So obviously I've drawn the molecular structure of caffeine on a banana.
The blemish in the middle of the first aromatic ring is unintentional.
Still it all goes towards my five a day.

Well this is a little embarrassing. I've just noticed that in my sleep deprived state I've missed an oxygen atom that should be double bonded to the carbon on the bottom left.