Your compensation, if any, is governed by the Conditions of Carriage you agreed to by purchasing the ticket, which in this case states (emphasis added)
RESPONSIBILITY FOR SCHEDULES AND OPERATIONS
American will endeavor to carry you and your baggage with reasonable dispatch, but times shown in timetables or elsewhere are not guaranteed and form no part of this contract. American may, without notice, substitute alternate carriers or aircraft and, if necessary, may alter or omit stopping places shown on the ticket. Schedules are subject to change without notice. American is not responsible for or liable for failure to make connections, or to operate any flight according to schedule, or for a change to the schedule of any flight. Under no circumstances shall American be liable for any special, incidental or consequential damages arising from the foregoing.
In the absence of any superseding regulation or legislation— of which there is none, as the origin and connection are both in the U.S., which does not regulate such matters— American is not required to give you anything. Despite the new routing, they still fulfill their fundamental obligation, which is to transport you from city A to city B. At best, you could request a refund for the ticket— though this would necessitate purchasing a new one, which being closer to departure is more likely to be more expensive. If you are an elite frequent flyer with them or on one of the more expensive fares, they may be willing to give you some miles or other token gestures for the inconvenience, but purely in the name of customer relations.
Some version of this paragraph is included in most airlines' contract of carriage. The airline is similarly under no legal obligation to compensate you, notably, for switching a nonstop flight to a connecting flight, a frequent complaint. The same goes for equipment changes— you may have purchased a ticket expecting a widebody in a three-class international configuration, but have no recourse if it gets swapped for a one-class turboprop at the last minute.