transformer
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bakers yeast enzyme nitroalkene reduction to nitroalkanes
Bakers yeast is able to reduce nitroalkenes to nitroalkanes in good yields, this cheap "reagent" could provide a good alternative to sodium
borohydride, the problem however is that this reaction does not seem to scale very well because there is 11g bakers yeast, 8.8 ml water and 50 ml
light petroleum ether required for every mmol of nitroalkene to be reduced.
Some researchers from the Institute for Chemical Research at the Kyoto University have published an article where they isolate the reductase enzyme
from bakers yeast and claim that in combination with the coenzyme NADPH they obtain good yields in the reduction of nitroalkenes to nitroalkanes,
unfortunateley they have not included much reaction details in their published work.
Advantages when using the isolated reductase enzyme is that reaction times are shortened, recycling of the reductase enzyme should be possible
provided that enzyme degradation is not too severe and only a sane ammount of solvents are required compared to bakers yeast. For example a 100mmol
nitroalkene reduction using bakers yeast would require 880 ml H2O, 5000ml light petroleum ether and over a Kg bakers yeast .
If there is a practical way to isolate a decent ammount of these reductase enzymes from bakers yeast then this method for reduction could very well be
competitive with common reagents and as a bonus it would would provide an all otc route for nitroalkene reduction to the corresponding amine.
The reduction of a nitroalkene by employing the reductase enzyme/NADPH could most likeley be done in a 2 phase system consisting of light petroleum
ether and water containing an acetate buffer for maintaining the pH at 5.0, using the NADH enzyme instead of the NADPH enzyme is supposed to give good
yields aswell.
Would a gel filtration setup provide a good method for isolating the reductase enzyme in considerable ammounts, or is there some better/cheaper
alternative?
And would it be possible to convert NADH to NADHP ?
Some refs:
Mechanism of the yeast mediated reduction of nitrostyrenes in light petroleum
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Asymmetric Reduction of cx,[ -Unsaturated Ketones with a Carbon-Carbon Double-Bond Reductase from Baker's Yeast
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Asymmetric synthesis of a nitroalkane by the use of novel nitroalkene reductases from baker’s yeast
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[Edited on 1-21-2011 by Polverone]
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jimwig
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Is this all theoretical - that is have you any hands on experience with any of these procedures?
This is a very interesting area and probably some research into the industrial application will yield a way to produce the reductase enzyme and or
the lage(r) scale production of nitroalkanes.
Thanks for the links.
JimWig
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