110543-84-5 2-(Ethylthio)-5H-(1)benzothieno(3,2-d)-1,3,4-thiadiazolo(3,2-a)pyrimidin-5-one 5H-(1)Benzothieno(3,2-d)-1,3,4-thiadiazolo(3,2-a)pyrimidin-5-one, 2-(ethylthio)-