Richard Edward Armer

Carbocyclic frenolicin analogues: novel anticoccidial agents.

Carbocyclic analogues of the antibacterial natural product frenolicin B have been synthesised. These analogues were active against parasitic protozoa of the genus Eimeria and represent a new series of anticoccidial agents. The synthesis of simplified analogues helped to define a possible pharmacophore for frenolicin.

8-aminoquinolines as anticoccidials - part III

Analogues of the antimalarial pentaquine, 1, in which the nature of the side-chain on the 8-amino position was varied, were prepared and evaluated for anticoccidial activity both in vitro and in vivo. Specifically, both the inter-nitrogen distance and the nature of the terminal amino group were investigated. Novel analogues of equal or improved efficacy in vitro and in vivo to pentaquine were discovered.

ANTICOCCIDIAL ACTIVITY OF NOVEL SEMI-SYNTHETIC ANALOGUES OF FRENOLICIN B(I)

Semi-synthetic aromatically substituted analogues of the naphthopyranquinone, frenolicin Β 1, have been produced and their biological activity as anticoccidial agents investigated in vivo. INTRODUCTION Coccidiosis is a devastating disease which causes severe economic losses in the poultry industry. Existing anticoccidials are becoming less effective as resistance has built up to many of the agents in commercial use and so the need to discover and develop new classes of coccidiostats which are not cross-resistant with existing agents is a significant challenge to the Animal Health industry. The naphthopyranquinone, frenolicin Β 1, has previously been reported to possess in vivo anticoccidial activity in broilers against the protozoan parasite Eimeria tenellaOur in vivo studies confirmed that Frenolicin Β 1 was efficacious in a standard 7 day chick model with activity at 2550ppm when dosed in feed against a polyether ionophore antibiotic resistant field isolate of Eimeria tenella. This encouraging efficacy led us to investigate the potential for semi-synthetic analogues of 1 to deliver improved anticoccidial activity.

ANTICOCCIDIAL ACTIVITY OF NOVEL SEMI-SYNTHETIC ANALOGUES OF DEOXYFRENOLICIN AND FRENOLICIN Β (PART II)

Semi-synthetic C-3a and C-4 substituted analogues of the naphthopyranquinones, frenolicin Β 1, and deoxyfrenolicin 2, have been produced and their biological activity as anticoccidial agents investigated in vivo. INTRODUCTION In a previous paper, we described the synthesis and in vivo anticoccidial activities of some semi-synthetic analogues of the naphthopyranquinone, frenolicin Β 1 in which modifications had been carried out in the benzofused ring of the naphthoquinone. Apart from phenolic pro-drugs derived from 1 these modifications led to less potent anticoccidial agents. It has previously been reported that deoxyfrenolicin 2 is virtually devoid of in vivo anticoccidial activity. In this paper we describe the synthesis and anticoccidial activity of some analogues of 1 and 2 in which modifications have been made at the C-4 and C-3a positions. U.K.