The following, based on your original parameters will do that
Dim sName As String
Dim sPath As String
Dim i As Long
i = Selection.Information(wdActiveEndPageNumber)
With ActiveDocument
sName = Left(.Name, InStr(.Name, ".") - 1)
sName = sName & ".pdf"
sPath = "C:\folder\"
MsgBox sPath & sName
ActiveDocument.ExportAsFixedFormat OutputFileName:=sPath & sName, _
ExportFormat:=wdExportFormatPDF, _
OpenAfterExport:=False, _
OptimizeFor:=wdExportOptimizeForPrint, _
Range:=wdExportFromTo, From:=i, To:=i + 1
End With