Site redirect help

Hi Folks,

Looking for a little help with something.

I have recently moved an element of my site to a sub domain on a VPS, the original site is still on shared hosting and running wordpress.

What I am trying to achieve is the following:

User hits site via the following link:

http://mysite.com/clients/could_be_a_number_of_things.php

I would like to have a redirect that sends them to:

http://clients.mysite.com/could_be_a_number_of_things.php

Where the “could_be_a_number_of_things.php” is kept

I have tried creating a directory in http://mysite.com called /clients

and put an .htaccess file in with the following:

//301 Redirect Entire Directory
RedirectMatch 301
https?://mysite.com/clients/(.*)
https://clients.mysite.com//$1

However I just get a 404 page from wordpress and no redirect.

Can anyone assist/advise?