using System;

using System.Linq;

using System.Collections.Generic;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        var myDict = new Dictionary<string,string>() { {"a","123"}, {"b","234"}, {"c","345"} };

        myDict.Dump();

        JsonConvert.SerializeObject(myDict).Dump();

        var myDictTransformed = myDict.Keys.AsEnumerable().Select(key => new MyDictEntry{ k = key, v = myDict[key] } );

        JsonConvert.SerializeObject(myDictTransformed).Dump();

    }

    class MyDictEntry 

    {

        public string k { get; set; }

        public string v { get; set; }

    }

}