Sorry you're having problems. Not sure what you've done so far to stop the behavior, but maybe spraying the door frame (NOT the cat) with something smelly like orange scented anti-scratch spray. And of course cat trees/scratchers. Cats have decided preferences for the surface upon which they like to scratch. You can get some inexpensive ones at your local, big-box pet store. It also helps to keep your cat's nails trimmed short.
And here is an article about problem scratchers.
Good luck!