Sciencemadness Discussion Board

Mandelic acid

hector2000 - 26-9-2010 at 01:38

As you know Mandelic acid prepared by below reaction



and also Mandelic acid is type of hydroxy acid

mandelamide perpared by reaction between mandelic acid+acetone +sulfuric acid and amonia

http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv3...
as you know acetamide prepared by heating ammonium acetate and heating ammonium mandelate should lead to mandelamide?!
also reaction betwen methyl or ethyl mandelate with ammonia too.
also i think this is possible from mandelonitrile?!



[Edited on 26-9-2010 by hector2000]

Hexagon - 26-9-2010 at 10:34

AFAIK you can make mandelic acid from benzaldehyde and chloroform in the presence of a strong base like sodium hydroxide, an alcohol would be required as a solvent. Check out chlorbutol synth. witch I think should be similar to this one.

mr.crow - 26-9-2010 at 10:58

You certainly could use the ammonium salt but it might have a lower yield or side reactions. Amides can be formed directly from esters, and the acetone condensation product looks like a reactive and easy to form ester.

Nitriles hydrolyze first into amides then into acids so you may be able to skip the extra step.

hector2000 - 28-9-2010 at 01:54

Quote: Originally posted by Hexagon  
AFAIK you can make mandelic acid from benzaldehyde and chloroform in the presence of a strong base like sodium hydroxide, an alcohol would be required as a solvent. Check out chlorbutol synth. witch I think should be similar to this one.

Reaction of benzaldehyde with chloroform in peresent of strong alkali lead to Trichloromethyl phenyl carbinol and i think hydrolyse of this componet should lead to mandelyl chloride
http://pubs.acs.org/doi/abs/10.1021/ja01679a028
(Reaction of mandelyl chloride with ammonıa should lead to mandel amide directly)

Methyl mandelate should perpared by reaction of Mandelic acid and methanol but yield is low anybody has idea for get better yield(sure catalysis needed.sulfuric acid is good choice?)?
also 'BORIC ACID CATALYZED AMIDE FORMATION FROM CARBOXYLIC ACIDS AND AMINES'
http://www.orgsyn.org/orgsyn/prep.asp?prep=v81p0262
I think ın this reaction i should use dry ammonia

Someone has idea for Resolution of Racemic mandelic acid?



[Edited on 28-9-2010 by hector2000]

hector2000 - 2-10-2010 at 03:46

This is possible for Resolution of Racemic Mandelic acid by (R)-(+)-α-Methylbenzylamine or (S)-(-)-α-Methylbenzylamine

http://www.sciencemadness.org/talk/files.php?pid=152589&...

(R)-(+)-α-Methylbenzylamine(1-Phenethylamine) is expensive and it prepared by:



Anyone has better idea for making (R)-(+)-α-Methylbenzylamine or (s)-(-)-α-Methylbenzylamine?
Or better way for Resolution of DL-Mandelic acid?

chemrox - 3-10-2010 at 20:47

Can't this be done by reducing the oxime with Fe/HCl ?

Lambda-Eyde - 3-10-2010 at 22:23

Quote: Originally posted by hector2000  
As you know Mandelic acid prepared by below reaction




Isn't that structure formula wrong? The chiral bond shouldn't be at the benzene ring, with all the carbons being sp<sup>2</sup> hybridized (planar configuration). Or am I missing something?

DJF90 - 4-10-2010 at 01:20

No its fine, its just not conventional. Think of the bond originatning from the a-carbon of the alcohol and you'll see that thats all that matters. Typically it would be the hydroxy group shown with undefined/racemic stereochemistry, as you should try and keep the carbon backbone as planar as possible, if that makes sense.