Barium (Newbee) 06-11-02 18:40 No 319846 |
2,4,5-triMeOP-2-P oxime (Rated as: excellent) |
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25,3 g (100mmol) 1-(2,4,5-trimethoxyphenyl)-2-nitropropen Yield 23,4g (98%) 1-(2,4,5-trimethoxyphenyl)-2-propanone oxime I have performed this reaction for about 6 months now. In the beginning I only got some 70% yield. But now, without having really changed anything, I get 97-98% everytime. Wierd! But I like it.. |
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Rhodium (Chief Bee) 06-11-02 19:45 No 319863 |
You keep impressing us | Bookmark | ||||||
Great! Do you have any references for this reduction, or is it your own invetion? |
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Barium (Newbee) 06-12-02 09:13 No 320101 |
Edit time.. | Bookmark | ||||||
It should say...100ml EtOH or IPA not 1000ml. Rhodium. Thank you.. I´ve read alot about CTH using hypophosphite donors. After trying a few of the published methods I started to modify them a bit, like less catalysts loading, diffrent solvents and so on. The result is this nice method. This method does, so far, not work with nitroethenes . |
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Barium (Newbee) 06-12-02 09:49 No 320112 |
EtOAC as solvent | Bookmark | ||||||
EtOAc can also be used as solvent in the CTH. This gives better yields of oximes which are sensitive towards hydrolysis. Such a reaction would look like this: Nitropropene 100mmol Sodium hypophosphite 300-400mmol (watch the color change) 5%Pd/C 2-3% w/w to the substrate EtOAC 50-60ml/25g substrate Water (warm) 1,5x the weight of sodium hypophosphite (15ml to 10g hypophosphite). IPA or EtOH as PTC, just a couple of mls. If substrate, catalyst, aqueous hypophosphite, EtOAc is combined in a flask nothing much happens until 4-5ml IPA or EtOH is added. A nice way to avoid ignition of the solvent is to add the catalyst first to the reaction flask, then the dry substrate. Make sure the substrate really covers the catalyst. Then add the EtOAc followed by the alcohol, and finally aq. hypophosphite in portions. |
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