[subject] The present invention provides the Prasgrel hydrochloride etc. which decreases the CATP content[wherein, R represents a protectin g group of the hydroxyl].[solution] In the method of manufacturing the Prasgrel hydrochloride shown by the above flow chart, it is characterized by controlling the reactive temperature at the low temperature in the step i of the process of manufacture of the Prasgrel hydrochloride as dropping or adding the chlorinating agent or after the chlorinating agent is dropped or added.本發明為提供減低CATP含量之普拉斯克列(Prasugrel)鹽酸鹽等[式中R為羥基之保護基]。上式所示普拉斯克列鹽酸鹽之製法，係以工程i中滴下或添加氯化劑時之溫度及氯化劑滴下或添加後之反應溫度控制於低溫為特徵之普拉斯克列鹽酸鹽之製法。
