can i install macosx 10.411 into 10.5 leopard system.

You refer to an article about Snow Leopard. You then mention Leopard and Tiger.

Please state your question more clearly, and also what Mac you have.

does http://support.apple.com/kb/ht1159 show your model ever shipping with 10.4.x ?

Here is OS X Tiger 10.4.11 running in VMWare Fusion 2 in Snow Leopard.

... and Mac OS X Leopard 10.5.8 running in Parallels 8 in Lion:

[click on images to enlarge]