www.example.com/products/223/category/sub_category/product_name.html

RewriteRule ^products/([^/]+)/([^.]+).html$ /$2/p$1 [L,NC,R=301]

www.example.com/category/sub_category/product_name/p223

www.example.com/products/223/category/sub_category/product_name.html

www.example.com/product-name/p223