$1 not working as intented

I am trying to redirect a webpage from http://www.test.com/isol/”name” to http://www.test.com/isol?company_name=”name”
I have created a redirect rule with source url: ^(.+)$
and target url : /isol?company_name=$1
as it was in the htaccess file.
The result i am getting is : http://www.test.com/isol?company_name=/isol/?company_name=/isol/

The reason why i cannot use the htaccess is because we migrated from apache to nginx.