| 摘要 |
Asymmetrically substituted pyromellitic diimides of formula: <CHEM> in which R1 and R2 are not the same and each represents hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, lower alkanoyl, benzoyl, di(lower alkyl)amino, lower alkanoylamino, benzoylamino, lower alkoxycarbonylamino or certain substituted phenyl or substituted lower alkyl radicals and each of X and Y is hydrogen, halogen or lower alkyl, are novel compounds that are obtainable by treating pyromellitic dianhydride with two appropriately substituted amines or with ammonia and one amine. The compounds can be administered to ruminant animals to increase their feed efficiency and suitable compositions for this purpose include the compounds with an inert carrier. |
