02-26-03 20:28
No 412006
Proanthocyanidins, flavonoid oligomeric phytochemical antioxidants found in many plants such as blue berries, bilberries and grapes, yield--upon vigorous oxidation with KMnO4--equimolar quantities of 2,4,6-trihydroxybenzoic acid and 3,4-dihyrdoxybenzoic acid, which can then be effectively separated from the reaction mixture with an HPLC or, on a large scale, perhaps even by means of fractional distillation.
These two compounds yield TMA-6 and 3,4-DM(M)A after standard clandestine chemistry operations, keeping in mind that EtNO2 can be made from ethyl chloride.
Conclusion:
This procedure illustrates a novel synthetic pathway to these highly interesting compounds from natural products without having to perform a formylation as is currently the case from a reading of PIHKAL. Furthermore, the ubiquity of the starting materials in nature makes their future availability seem less uncertain, precluding of course all out nuclear annihilation at the hands of unthinking leaders on planet Earth in the near future.
(Chief Bee)
02-26-03 22:41
No 412041
It would be very much appreciated if you could come up with a more detailed procedure for the oxidation, with references, yields etc.
(Newbee)
02-27-03 18:12
No 412298
Do a search on Beilstein under "benzylic oxidation using potassium permanganate" and then be sure to use an excess of KMnO4 (which is cheap anyway) in order to ensure at least a one to one molar ratio of KMnO4 for every benzene ring to be oxidized.
If the example given by Beilstein is toluene + KMnO4 --> benzoic acid, for example, then simply substitute proanthocyanidin for toluene and use twice as much KMnO4 as is called for in the procedure.
(Hive Addict)
02-27-03 18:16
No 412302
Do a search on Beilstein under "benzylic oxidation using potassium permanganate" and then be sure to use an excess of KMnO4 (which is cheap anyway) in order to ensure at least a one to one molar ratio of KMnO4 for every benzene ring to be oxidized.
Sure, but if I had to look up everything myself in Beilstein, I would know the whole collection by heart by now. So, do us a favour and at least give book nr, page etc. Some of us really have other things to do then just making 3 mile walks to the library to become frustrated of the fact the library has the paper Beilstein version since it doesn't have the money to buy an online account....
Abusus non tollit usum
(Newbee)
02-28-03 18:25
No 412578
I really don't care that much about it either.