I recently changed my permalinks from /%postname%/ to /%category%/%postname%/

And I have just set up 301 redirects in my htaccess to redirect some old posts (that have incoming links to the old structure).

However one of them ends up in an infinite loop. Essentially the %postname% and %category% are the same and that seems to be causing the problem

So my 301 command is:
redirect 301 /the-phrase/ http://mydomain.com/the-phrase/the-phrase/

And if I try to go to /the-phrase/ I end up in a loop.

I also tried to redirect it to another page (home page)
redirect 301 /the-phrase/ http://mydomain.com/

This works. BUT it breaks the links for anything in that category so
/the-phrase/another-post/
will then try to redirect to
http://mydomain.com/another-post/ .... which doesn't exist

Any ideas how I can get this redirect to work?

I want the specific URL http://mydomain.com/the-phrase/ to redirect to http://mydomain.com/the-phrase/the-phrase/ and nothing else to be affected

Any assistance much appreciated

Cheers
Brett