gistfile1.txt

add_action('init','safe_remove_backend_admin_access_for_role');

function safe_remove_backend_admin_access_for_role(){
	if( current_user_can('editor') || current_user_can('administrator') )//Your roles
		return;
  	if( is_admin() && !defined('DOING_AJAX') ){//IMPORTANT! Front end AJAX events are excluded...
      if(isset( $_GET[ 'action'] ) && 'trash' == $_GET[ 'action'])//Perhaps you have a call to some WP Admin Operation that needs whitelisting...
        return;
          wp_redirect( home_url() );
          exit;
      }
}