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....