Please, how can I make this simple operation:

I wish that every requests for uris like:
http://example.com/adm
or:
http://example.com/adm
Goes to the wordpress login page:
wordpress/wp-login.php
(The wordpress installation is inside the folder "wordpress").

I've tried:

location /adm/ { alias wordpress/wp-login.php; }
location /adm { alias wordpress/wp-login.php; }

and:

rewrite ^/adm$ wordpress/wp-login.php;

But with no success...

Just in case someone asks, this is my serve conf. file:

server {
server_name www.example.com;
rewrite ^ http://example.com$request_uri? permanent;
}

server {
server_name example.com;

access_log /var/log/nginx/example.com.access;
error_log /var/log/nginx/example.com.error;

root /var/www/example.com;

index index.htm index.php;

location / {try_files $uri /wp$uri/ /wordpress/index.php$args;}

location ~ .php$ {
try_files $uri =404;
#fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include /etc/nginx/fastcgi_params;
}

location = /favicon.ico {log_not_found off;access_log off;}
location = /robots.txt {allow all;log_not_found off;access_log off;}
location ~ /\. {deny all;access_log off;log_not_found off; }
}