While MCT does not apply because this is not a connection, the fact that carriers will not sell this as a connection tells you that they do not want the risk of a misconnect.
AA requires passengers at the departure gate no later than T-15. While AA will not generally offload a pax until the flight is closed, it will do so if it needs the seat or if the aircraft is ready to go and all passengers at the gate have boarded. Thus, this gives OP 15 minutes to make it from brakes locked on the inbound to the gate reader on the outbound. That seems unlikely and the risk means that he purchases a new ticket to BOS.
Agree with others that unless schedule and other factors do not work, flying this as LAX-BOS may make a lot more sense. I would, in any event, price the ticket with the change. It might not be far off.