using System;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        var str = "{\"access_token\": \"12345678901234567890\", \"token_type\": \"bearer\"}";

        dynamic myObject = JsonConvert.DeserializeObject(str);

        Console.WriteLine(myObject.access_token); //prints 12345678901234567890

        Console.WriteLine(myObject.token_type); //prints bearer

    }

}