when I use RewriteCond without the variable (parentheses) it does not work
Whoops! There's a second reason for using parentheses, and that's what we're dealing with here.
Those aren't capturing parentheses. That is, they could be, but they're not needed for that job. They are needed as grouping parentheses. Here they're combining two different options... which I now realize can pefectly well go in brackets instead:
That only works if you're looking at THE_REQUEST without anchors. If your RewriteCond is instead looking at the QUERY_STRING, you need parentheses (^|&) because you're separating two different symbols: either the anchor ^ or the literal character &.
What happens to requests after they've been redirected to www.example.com/info or similar? Technically you could have a file named "info" without extension, but it doesn't seem awfully likely. Is there rewriting somewhere else?
Second issue: If you're redirecting a whole bunch of different pages distinguished only by the query string