The Hive > Serious Chemistry
Biosynth: Homebrewing Ephedrine
jim:
I refer you to this tid bit of info.
__________________________________
!!!! I FORGOT TO QUOTE THAT THIS REACTION IS STRONGLY pH DEPENDENT AND
BEST PROCEEDS AT A pH OF 8-9. !!!!!
From Agric. Biol. Chem., Volume 50, yr 1986, page 1261
"Reductive C3-Homologation of Substituted Benzaldehydes by
Fermenting Bakers' Yeast
...
... A unique reaction catalyzed by Bakers' Yeast is the reductive C-C bond formation in
benzaldehyde that results in the formation of 1-phenylpropane-1,2-diol [ref 3]. This reaction is
supposed to involve the attack of pyruvic acid, which is formed from sugars through a well known
pathway, by benzaldhyde to give phenyl-1-hydroxy-2-propanone [ref 4]. This ketol is considered to
be reduced by alcohol dehydrogenase of the yeast to give the
diol. ...
...
Reduction of aldehydes by fermenting yeast. General procedure. To 50 mL of tap water, 12.5 g
of dry yeast and 10 g glucose were added, followed by stirring
at room temperature for 10 minutes. Then a solution of aldehyde 1 (about 600 mg) in 1 mL of
ethanol was added to the suspension of fermenting yeast with stirring. After 1 hour yeast (6.2 g)
and glucose (5 g) were added to the reaction mixture, followed by stirring for an additional 3.5
hours. The reaction mixture was then poured into a beaker containing 35 grams of celite and
extracted with 100 mL of ethyl acetate three times. The combined organic layer was dried over
anhydrous Na2SO4. The solvent removed under reduced pressure to give an oil consisting of
benzylic alcohol 3, 1-arylpropane-1,2 diol 3, and in
some cases, 1-aryl-1-hydroxy-2-propanone 4. ...
Table II. Yields and Steroselectivities of propanediols (a)
_____________________________________________________________
Substrate______Yield %____...
______________________________________________________________
H______________30
p-OMe__________22
p-Me____________28
p-Cl____________27
p-F_____________26
p-NO2__________14
o-Me____________7
o-Cl_____________32
o-F_____________30
m-F____________31
CF3(e)__________0
_________________________
(a) Reactions were carried out in tap water at room
temperature ... (e) All of the o-, m-
p-substituted isomers gave no diols."
_________________
If i remember correctly, the diol can be rearranged to form P2P with H2SO4
Jacked:
You suggest using acetone as the non-polar solvent... wouldnt acetone bee
miscible with the sugar beet juice?
At the point in the procedure that the acetone is used, the sugar beet
juice has been fermented.
The solvent will collect what it is after, and seperate (layer).
You use 200mL solvent for each extraction - isnt this far too little for 4.5gallons of solution?
Most of the 4.5 gallons is junk that you are not interested in. The 200Ml
per extraction is conservative, you may use more if you wish, the only
complication is the added seperation/evaporation time.
Would this work for substituted benzaldehydes?
It would depend on the substitution
Is it really necessary to vac-distil the L-PAC before doing a reductive
amination?
Yes. Without the vacuum distillation you will not be aminating only the
desired substance. I am unsure what contaminates may reside in the
undistilled form. For safety's sake, I would not skip this step.
Answers were given to these questions by the writer of the original post.
http://crystalninjas.net/jacked/disclaimer.htm
Whizard:
In your quotation from the journal you say:
The solvent removed under reduced pressure to give an oil consisting of
benzylic alcohol 3, 1-arylpropane-1,2 diol 3, and in
some cases, 1-aryl-1-hydroxy-2-propanone 4. ...
What is the 4. part of the last word? I do not want to assume anything!!!
It also appears that the large excess of yeast is used to allow immediate gratification to the above mentioned experimentalists!
I dunno, but I been told ... You never slow down, you never grow old!
jim:
To clarify:
"... benzylic alcohol 3, 1-arylpropane-1,2 diol 3, and in
some cases, 1-aryl-1-hydroxy-2-propanone 4. ..."
the 3, and 4 refer drawings of the compounds on diagram not included.
Antoncho:
....having read the proc. about getting -propanediol from benzaldehyde, i couldn't help wondering about 2 things:
1) The procedure doesn't mention any sort of pH adjustment - how is pH supposed to get to 9? It also just looks strange - what is the origin of that 1st phrase, the one in CAPS? Jim, you still around? Please, explain!
2) Apart from the pH thing, the whole procedure seems completely identical to l-PAC production!! What is you think that makes the difference?
Antoncho will bee VERY appreciative of any help on this issue, cause SW He Doesn't Even Know just happens to have a kilo of benzaldehyde lying around with no use for it :):):)
Thank you all in advance,
impatiently awaiting
Antoncho
P.S. Dear Moderators, do you really think this thread belongs here? - if mr. Jacked doesn't mind...
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