The time is ripe for a short chemistry quiz. In fact, a very short one – it’s only one question long. We used to traumatize undergraduates with this one towards the end of the first organic chemistry lab course. I can’t remember if a student ever got it right, and I’m certainly not sure whether it was correct to use this example, from a pedagogical point of view, as the correct answer when disclosed typically resulted in total confusion with the poor newcomer to the field. To my defense, we never used it on the final exam.
Let’s cut to the chase. Familiarize yourself with compounds 1 and 2; one is a thiophene and the other a benzene.
In what respect are the two compounds identical?
Hint #1: Nope, it’s not the molecular formulas. C4H4OS ≠ C6H6S
Hint #2: I’m well aware that the main tautomer of 1 is the keto-form. For this to work however, compound 1 has to be drawn in this way.
The first person who provides the correct answer in a comment below will receive an autographed copy of my thesis (sent anywhere in the world). I know it’s not much. That’s what I can afford to lose for the time being. Its value is negligible in comparison to this edition.
Anyways… good luck!
UPDATE: Jesus H. Christ, that was quick! 20 minutes after posting, two prominent readers submitted the winning answers almost at the same time. The answer is “thiophenol”. (Thiophen-ol vs. thio-phenol.) Congrats!