There is no wake turn standard between 2 medium aircraft (i.e. b737 a320), a medium following a heavy (a330 b767) then 2 minutes is required OR 5 NM (from airborne), same with a light behind the medium. This is assuming they are both departing from the same taxiway, otherwise 3 minutes is required.
49 seconds seems too close, I find they take longer then that just to roll down the runway and get airborne, if big jets means heavy, you need at least 4 NM, which is about 1.5 minutes pushing traffic.