It's a legal connection, but my personnel preference is to allow at least a 2-hr connection when connecting domestic to international, especially if I have upgraded the international portion (which is almost 100% of the time). If your connecting flight is delayed for any reason, you could have a problem getting rescheduled on to another flight that would meet your schedule needs (if you have any and I usually do). And if you have another connecting flight at your international destination, things get even worse. So I play it on the safe side and take an earlier domestic flight to make sure I have a minimum of a 2-hr layover.