Debug in csc.exe

Hi,

I have a problem in csc.exe

I am trying to build an assembly through command prompt(csc.exe)

Here is simple example simulated

Source code:
static void Main(string[] args)
{
#if DEBUG
Console.WriteLine("Debug");
#endif
Console.WriteLine("Normal");
System.Threading.Thread.Sleep(2000);
}

Command:
csc.exe program.cs /debug

Then when I run the exe, it doesnt goes into the DEBUG constant
But when I build using IDE, then things are fine.

Please help.

Thanks,
Prince