- Anticoccidial activity of dithiosemicarbazones
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Dithiosemicarbazones (di-TSC) with one or two basic substituents were found to be highly active against a variety of Eimeria species (coccidia) in chicks after both prophylactic and therapeutic application. As to the structure-activity relation, it could be shown that the necessary prerequisites of activity were a di-TSC structure in which at least one radical of the TSC part of the molecule carried a basic function, and the C=S group in TSC being freely enolizable, i.e., both nitrogen atoms next to the C=S group carrying another hydrogen atom. If the C=S groups were replaced by C=O or C=NH to form either disemicarbazones or diguanylhydrazones, the compounds obtained were ineffective. The limitation of action to di-TSC with basic substituents of a small volume suggested that the basic radical was of great importance for the absorption of the compound by the mucosa and penetration into the coccidia. The activity against coccidia was clearly attributable to the whole molecule, since the parts resulting from degradation (possibly by hydrolysis), e.g., α,β-dicarbonyl compounds and their derivatives, such as dihydrazones or thiosemicarbazides with basic substituents, or isothiocyanates with basic substituents, were completely ineffective.
- Winkelmann,Wagner,Wirth
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p. 950 - 967
(2007/10/05)
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