Private Sub Command1_Click()
    Dim Pos1 As String
    Dim Pos2 As String
    Const IniPos As Integer = 1
    Pos1 = InStr(IniPos, RichTextBox1.Text, "{", vbTextCompare)
    Pos2 = InStr(Pos1, RichTextBox1.Text, "}", vbTextCompare) - 1
    '   // Sin Reemplazar los caracteres
    RichTextBox1.SelStart = Pos1
    RichTextBox1.SelLength = Pos2 - Pos1
    RichTextBox1.SelColor = vbRed
End Sub