I am trying to get the product details by hitting this url but getting 404 error any help would be appreciable ??
As your question is not very precise, shows no effort that you have tried to make it work and we know nothing about your configuration one can only guess:
Could be that you are missing a rewrite rule in your .htaccess file
RewriteRule ^api/rest api.php?type=rest [QSA,L]
Did you enable that call for Guest user via system configuration? Otherwise you have to do oauth before!