Drag mp3's to my iphone

Hi,

I updated to the latest itunes 11.0.1 and I still have the same problem which is the follwing :

I have mp3's on my macbook air and I can't just drag them to my music folder using itunes 11.0.1 to my iphone 5

I use a 3rd party mp3 player just to be able to transfer those mp3's to my iphone 5 and listen to them through that mp3 app

Any tips or solution will be much appreciated because I prefer to use the itunes player on my iphone


Thanks