The Vespiary

The Hive => Chemistry Discourse => Topic started by: Antibody2 on June 03, 2002, 04:15:00 PM

Title: Will KMnO4 oxidise an allybenzene
Post by: Antibody2 on June 03, 2002, 04:15:00 PM

will KMnO4 oxidise an allybenzene to its benzaldehyde, or does the allybenzene need to be isomerized  to a propenylbenzene first? Any thoughts on how to reduce solvent volume on this rxn would be also be appreciated.

thanks as always :)

Title: Sure
Post by: Chromic on June 03, 2002, 06:38:00 PM

Sure it will, but it will happen at the wrong position. Every synthesis I've seen wants to make a 1,2-glycol or epoxide or acetyl/formyl glycol, not the 2,3-glycol etc. (I would expect a 2,3-glycol to rearrange to the terminal ketone (ie aldehyde) but maybe you'd get a 2-propanone? more input needed on that topic...) Without access to good analytical equipment, I think I'd choose to isomerize to be safe.

Reducing solvent volume should be easy, accomplished by slowly dripping a more concentrated solution of KMnO4 onto the solution. More experimental details are needed on that area, I haven't seen anyone attempt it yet.

Title: Why
Post by: Vibrating_Lights on June 03, 2002, 08:37:00 PM

Why would you want a benzaldehyde instead of a ketone? Trying to explore a  new PEA.
VL_

Title: Trying to explore a new PEA.
Post by: Antibody2 on June 03, 2002, 09:15:00 PM

Trying to explore a new PEA. or the hypothetical viability of one.

chromic - yah, its just such a lousy yeilding rxn, that it seems more attractive if it could be done with a raw material. Adding two steps adds 40% to overall process.