2D wall rotation?

I’ve attatched this code to a 2D sprite of which I want to rotate 90 degrees under 3 seconds but I don’t really seem to make it work properly.How do I use Time.deltaTime in this case or am I suppose to use anything else to make it work?

var klick : int;
function Start () {
	
}

function OnTriggerStay2D(other : Collider2D)
{
	var rotationTime : float = Time.deltaTime * 3;
			if (klick == 1)
			{
				GameObject.Find("Door_1").transform.Rotate(Vector3.forward * 90 * rotationTime);
			}
			
			if (Input.GetButtonDown("Fire1"))
			{
				klick = 1;
			}
			else 
			{
				klick = 0;
			}
}

Create a coroutine and call it once the rotation is triggered. Inside the coroutine create a loop and rotate the wall by a small amount on each iteration, and yield inside the loop.

This might help Coroutines - Unity Official Tutorials - YouTube

Just replace the movement & position logic from the video with rotation & angle.