Sciencemadness Discussion Board

Nitrostyrene -> Imine -> Ketone

myristicinaldehyde - 11-5-2016 at 13:46

2 Questions:

1. What is the name of the nitroalkane addition to an aldehyde reaction? Is it a Henry, Nitroadol, or Knoenvagel reaction? What is the difference? (It seems the confusion from the drug forums has spread!)

2. Would reducing the nitostyrene with zinc or iron in ethanoic acid to a a,b-unsaturated amine arrange into a ketone via imine? I remember seeing that somewhere on the forum.
- hydrogen goes over to neighboring double bond, forming a saturated imine
- imine reacts
- ????
- ketone
If this is "valid", it should be a very interesting route to phenolic ketones
I am looking to see what fun things I can make from a vanillin-nitroethane condensation product. I didnt make it yet, though!

Thanks for the help!

Metacelsus - 12-5-2016 at 06:43

1) Answer: all of the above

The Henry reaction is just another name for the nitroaldol reaction: https://en.wikipedia.org/wiki/Nitroaldol_reaction
The Knoenvagel reaction is a more general term, and includes substrates other than nitroalkanes: https://en.wikipedia.org/wiki/Knoevenagel_condensation

2) In those conditions, probably yes. The acid would promote conversion of the imine to the ketone. Under other conditions (like catalytic hydrogenation), the amine will be formed.

myristicinaldehyde - 12-5-2016 at 11:08

Quote: Originally posted by Metacelsus  
1) Answer: all of the above

The Henry reaction is just another name for the nitroaldol reaction: https://en.wikipedia.org/wiki/Nitroaldol_reaction
The Knoenvagel reaction is a more general term, and includes substrates other than nitroalkanes: https://en.wikipedia.org/wiki/Knoevenagel_condensation

2) In those conditions, probably yes. The acid would promote conversion of the imine to the ketone. Under other conditions (like catalytic hydrogenation), the amine will be formed.


Thanks!

Out of curiosity, what if I add a stearically hindering group like a tert-butyl to the imine? Would it hydrolyze to form the corresponding amine as normal, or would the reaction fail to take place?