This is absolutely terrific. I was ready to throw my book out the window when it got to this chapter. Now, it is all beginning to come together. Thank you!
Thanks Joe, clear and useful explanation. Really appreciated how you pointed out where reactants "end up" in the pyridine ring. Keep up with the great work
hey Joe, love your work, it helps me a lot! I don't really understand why you protonate your keto-ester in the imine-formation at about 9:20, we are working in a basic environment because of the ammonia, right? it also seems a little unnecessary and complicated as you can write the mechanism without out the protonation just as well.
Hi, Ricola! I had taken this directly from a textbook (Volhardt Organic Chemistry: Structure and Function), but I think you bring up a good point. This is a complex, multistep reaction and in reality protons are being picked up/falling off all the time and very quickly. Of course you can't just introduce acid and base out of thin air, but in this scenario, with so many components, there would be multiple steps where you could introduce acid/introduce the ammonia. If your course differs slightly in how the acid-base steps are executed, please follow what your instructor shows (I'm not your teacher/not giving anyone any grade 🙂). jOeCHEM/this channel will always differ slightly from what an individual student may experience in their class, but if you're carrying out a Hantzsch Pyridine Synthesis the overall approach will be almost the same. Does that make sense?
If I remember right, when you add your ammonia that closes your block giving you your piperidine/piperdone I think the later. And if you use a different chem(brain not working) your reaction goes right making a completely different out come
Would you not have to partially protonate the -OH even in basic conditions because -OH is a poor leaving group? I'd imagine that's possible at a pH of ~ 8.5. Chem Libre talks about pH ~ 5 for imine formation.
If I could I would. ...am back at it again....so I didn't sit 🪑 my exam so I have to do it this time round .....I didn't finish watching the video last cont'd from 18:36.
