using System;

using System.Linq;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        string json = @"

            {

              ""list"": [

                {

                  ""code"": ""c1_1"",

                  ""value"": ""1""

                },

                {

                  ""code"": ""c1_2"",

                  ""value"": false

                }

              ]

            }";

​

        var obj = JObject.Parse(json);

        obj["list"] = new JObject(

            obj["list"].Children<JObject>()

                       .Select(jo => new JProperty((string)jo["code"], jo["value"]))

        );

        json = obj.ToString();

        Console.WriteLine(json);

    }

}