Converting JS to C# Problem

Hi guys im trying to convert my javascript to C# but there is have a problem with code;

 using UnityEngine;
 using System.Collections;
 
 public class Pause : MonoBehaviour {
      isPause= false;
     Rect MainMenu = new Rect(10, 10, 200, 200);
     
     void  Update (){
         if(CFInput.GetKeyDown(KeyCode.Escape))
         {
             isPause = !isPause;
             if(isPause)
                 Time.timeScale = 0;
             else
                 Time.timeScale = 1;
         }
     }
     
     void  OnGUI (){
         
         if(isPause)
             
             if(GUI.Button(new Rect(Screen.width/2.5f,Screen.height/6,Screen.width/5,Screen.height/7), "Main Menu"))
         {
             Application.LoadLevel("MainMenu");
             Time.timeScale = 1;
         }
         if(isPause)
             
             if(GUI.Button(new Rect(Screen.width/2.5f,Screen.height/2.5f,Screen.width/5,Screen.height/7), "Restart"))
         {
             Application.LoadLevel("Level1");
             Time.timeScale = 1;
         }
         if(isPause)
             if(GUI.Button(new Rect(Screen.width/2.5f,Screen.height/1.6f,Screen.width/5,Screen.height/7), "Exit Game"))
         {
             Application.Quit();
         }
         
         
     }
 }

there is have problem with 'isPause= false' it's says ;

"Unexpected symbol `=' in class, struct, or interface member declaration"

i hope you guys can help thanks.