using System;

using System.Collections.Generic;

using Newtonsoft.Json;

​

public class Program

{

    public static void Main()

    {

        var a = new BaseClass(){ Type = 0 };

        var b = new DerviedClass(){ Type = 1, Name = "Hello" };

        var list = new List<BaseClass>(){a,b};

        var json = JsonConvert.SerializeObject(list);

        Console.WriteLine(json);

        var intermediate = JsonConvert.DeserializeObject<List<dynamic>>(json);

        var result = new List<object>();

        foreach( dynamic item in intermediate )

        {

            if( item.Type == 0 ) result.Add( new BaseClass(){Type = item.Type});

            if( item.Type == 1 ) result.Add( new DerviedClass(){Type= item.Type, Name= item.Name});

        }

        Console.WriteLine($"[{string.Join(", ",result)}]");

    }

}

​

public class BaseClass

    {

        public int Type  {get; set;}

    }

    public class DerviedClass:  BaseClass   

    {

        public string  Name  {get; set;}

    }