.htaccess redirect not working

Hi All

We are changing the URL structure of our site from:

http://www.example.com/products_new/%product-name%

to

http://www.example.com/products/%product-name%

I have put the following mod rewrite rule in the .htaccess file

RewriteEngine On
RewriteBase /
RewriteRule  ^products_new/(.*)$ /products/$1 [R=301,NC,L]

It seems it is not taking the redirect :(

Any help is appreciated.