the present invention relates to a novel method for preparing 1 -- 7 - methoxyquinazolin - 6 - yloxy ) piperidin - 1 - yl ) prop - 2 - en - 1 - one in a simpler process as compared with conventional methods by allowing 4 -- 7 - methoxyquinazolin - 6 - ol to react with an n - acyl piperidine derivative in an inert polar protic solvent in the presence of a base .