Linq Query remove duplicates from list

Hi

I had question related to this Refactor C# code.

The source classes for DTO's are the in the above question. I want to remove duplicates created in salesorders List based on productCode ( mapping values[1] )

The issue is each List has as child list variable called scns (values[5]) which also needs to be created from the source data

 req.salesOrders = (from docArray in resp.transaction.quote_data.sub_documents
                                   let document = Regex.Split(docArray, @"\$,\$")
                                   let values = document.attributes[0].value.ToString().Split(new[] { "**" }, StringSplitOptions.None)
                                   where (document.attributes != null && document.attributes.Length > 0) && !string.IsNullOrWhiteSpace(document.attributes[0].value.ToString()) && !string.IsNullOrEmpty(values[3]) && (!string.IsNullOrWhiteSpace(values[5]) && values[5] != "$$")
                                   select new salesOrder()
                                   {
                                       productCode = values[1],
                                       salesOrderType = values[2],
                                       startDate = DateTime.Parse(values[3]).ToString("yyyy-MM-dd"),
                                       pays = !string.IsNullOrWhiteSpace(values[4]) ? int.Parse(values[4]) : 0,
                                       scns = (from code in values[5].Split(new[] { "$$" }, StringSplitOptions.RemoveEmptyEntries)
                                               select
                                               new scns()
                                               {
                                                   scnCode = code
                                               }).GroupBy(o => o.scnCode).Select(g => g.First()).ToList()

                                   }).ToList() ;


Example req.salesOrders  should have single record for req.salesOrders=10  (product) this should be unique.   All the req.scns

> 1**10**New Client**2016-11-02**250**F0040Z$$F0040Z$$F00141$,$1**,1W**New Client - Add2 Product**2016-11-02**250**F71900$$F0070X

> 1**10**New Client**2016-11-02**250**F00498$$F00493$$F00141

Example in above it should return
{
productCode = 10
 salesOrderType =New Client,
 startDate = '2016-11-02',
 pays = 250
 scns = {F0040Z,F00141, F00498,F00493}  //removed dups . this is implemented
}
{
productCode = 1W
 salesOrderType =New Client - Add2 Product,
 startDate = '2016-11-02',
 pays = 250
 scns = { F71900,F0070X}
}