Anthelmintic thio-barbituric acid derivs. - have (5)-benzyl-thiocarbamoyl substit. and are esp. useful for control of liver flukes

摘要

Thiobarbituric acid derivs. of formula (I) and their salts with suitable bases are new. In (I), R1 and R2 are each H, opt. branched and/or unsatd. 1-4 C alkyl, or are phenyl or benzyl opt. substd. by 1 or 2 F, Cl or Br. R3, R4 and R5 are each H, F, Cl, Br or CF3. They are prepd. by reacting the appropriate, opt. N-substd. thio-barbituric acid with a benzilisothiocyanate. (I) are anthelmintics for use in human or veterinary medicine, and esp. effective against the liver fluke Fasciola hepatica. Their safety factors are much higher than those for clioxanide and niclofolan, e.g. 5-(3,4-dichlorobenzylthiocarbamoyl)-1,3-dimethyl-2-thiohexahydrop- yrimidin-4,6-dione at 30 mg/kg. gave complete clearance of F. hepatica from infected lambs with a safety factor of 50.