Is the fast of one who remains in a state of janābah until Dhuhr or Asr valid, then purifies himself before the Adhan of Asr or Maghrib, while being negligent in prayer?

If ritual impurity (janabah) occurs at night or by nocturnal emission during the day, the fast is valid. However, if janabah results from intercourse or the emission of semen while awake during the day, the fast is invalidated. Expiation (kaffarah) along with making up the fast (qada') is obligatory in Ramadan if it was due to intercourse, by scholarly consensus. If it was due to the emission of semen from masturbation or foreplay without intercourse, there are two opinions regarding the obligation of expiation. The questioner must not delay performing the ritual bath (ghusl) for janabah, as it leads to missing the prayer or delaying it beyond its prescribed time.