This is a very complicated molecule so I'm not going to ask for the IUPAC name. You can win with the common name but be sure to get it right!
This molecule has played a very important role in elucidating some basic concepts in molecular biology but its structure is rarely shown in 21st century biochemistry textbooks.
Post your answer in the comments. I'll hold off releasing any comments for 24 hours. The first one with the correct answer wins. I will only post
correct answers to avoid embarrassment.
There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your comment.) Every undergraduate who posts a correct answer will have their names entered in a Christmas draw. The winner gets a free autographed copy of my book! (One entry per week. If you post a correct answer every week you will have ten chances to win.)
Some past winners are from distant lands so their chances of taking up my offer of a free lunch are slim. (That's why I can afford to do this!)
In order to win you must post your correct name. Anonymous and pseudoanonymous commenters can't win the free lunch.
UPDATE: The molecule is rifampicin, an inhibitor of bacterial RNA polymerase. The winner is Philip Rodger. Congratulations Philip, please send me an email message so we can arrange lunch.
Winners
Nov. 2009: Jason Oakley, Alex Ling
Oct. 17: Bill Chaney, Roger Fan
Oct. 24: DK
Oct. 31: Joseph C. Somody
Nov. 7: Jason Oakley
Nov. 15: Thomas Ferraro, Vipulan Vigneswaran
Nov. 21: Vipulan Vigneswaran (honorary mention to Raul A. Félix de Sousa)