using System;

using System.Linq;

using System.Text.Json;

using System.ComponentModel.DataAnnotations;

using System.Reflection;

public class Program

{

    public static void Main()

    {

        var child = new Child("p1", "p2");

        var properties = child.GetType()

            .GetProperties(BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance | BindingFlags.NonPublic);

        var propertiesWithRequiredAttribute = properties

            .Where(x => x.IsDefined(typeof(RequiredAttribute)));

        Console.WriteLine(

            JsonSerializer.Serialize(properties.Select(x => x.Name))

        );

        Console.WriteLine(

            JsonSerializer.Serialize(propertiesWithRequiredAttribute.Select(x => x.Name))

        );

    }

}

​

public abstract class Parent

{

    [Required]

    protected string Property1 { get; set; }

}

​

public class Child : Parent

{

    public string Property2 { get; set; }

    public Child(string name1, string name2)

    {

        Property1 = name1;

        Property2 = name2;

    }

}