Adding $ on redirect stops working, rewriteRule not working – Apache

PHP Version 5.4.16

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Problem

I’m trying to redirect some pages from my website to the home of another website, but I can’t seem to make it work.
Currently i have this:

redirect 301 /portalwebhttp://www2.tha.com.br

It works if the url is exactly www.oldwebsite.com.br/portalweb.But if add anything after the portalweb it redirects to this: http://www.mywebsite.com.br/anything

I have tried the following solutions:

redirect 301 /portalweb$ http://www.mywebsite.com.br

Redirect "/portalweb$" "http://www.mywebsite.com.br/"

RedirectMatch ^portalweb/$ http://www.mywebsite.com.br

RewriteEngine On
RewriteRule    "^portalweb$"  "http://www.mywebsite.com.br/" [R,L]
RewriteRule    "^portalweb/$"  "http://www.mywebsite.com.br/" [R,L]

When i add any of the solutions above, it just doesn’t work at all. It seems that the $ character make the redirect not work.

Thanks in advance.