There is no system of five times daily compulsory prayer discussed anywhere in the Qur’an. It teaches to be in prayer continuously day & night. The word SALAAT(often translated as prayer) in Qur’an refers to the disposal of duties and responsibilities in the absolute transparent way in favour of TRUTH, EQUITY & JUSTICE. The five times prayer as of now is an innovation punched in from the Zorastrian system of Prayer. Zorastrians pray five times a day in the same times as Muslims do today. To know in more details please read the book-“Fajarul Islam” by Allama Mohammad Ahmed Misri & Book on Comparative Religion by Masi.