Michael J. Witty

Synthesis and evaluation of 2-pyridyl pyrimidines with in vitro antiplasmodial and antileishmanial activity

A series of 2-pyridyl pyrimidines, reported inhibitors of Plasmodium falciparum methionine aminopeptidase 1b were synthesized and evaluated for their antiplasmodial activities. An analysis of physicochemical properties demonstrated a link between lipophilicity and antiparasitic activity. Cross screening of the library against cultured Leishmania donovani parasites revealed this class of compounds as potent inhibitors of parasite development in vitro.

Enantioselective preparation of 2-substituted- 1,3-dithiane 1-oxides using modified sharpless sulphoxidation procedures

Abstract Enantioselective sulphoxidation of a wide range of 2-substituted-1,3-dithianes has been carried out using modified Sharpless conditions to furnish the corresponding sulphoxides in optically enriched form. Deacylation of 2-acyl-1,3-dithiane 1-oxide derivatives allows the preparation of 2-alkyl-1,3-dithiane 1-oxides and the parent 1,3-dithiane 1-oxide itself in high enantiomeric excesses.

Chloroquine–astemizole hybrids with potent in vitro and in vivo antiplasmodial activity

A dual activity, conjugated approach has been taken to form hybrid molecules of two known antimalarial drugs, chloroquine (CQ) and the non-sedating H1 antagonist astemizole. A variety of linkers were investigated to conjugate the two agents into one molecule. Compounds 5-8 possessed improved in vitro activity against a CQ-resistant strain of Plasmodium falciparum, and examples 7 and 8 were active in vivo in mouse models of malaria.

Current strategies in the search for novel antiparasitic agents.

The market for antiparasitic products comprises the largest segment for sales of livestock and companion-animal healthcare agents. Despite the availability of highly effective, broad-spectrum agents, there remains a need for safer, more convenient and more environmentally friendly products that will overcome the ever-present threat of resistance development. The very high cost of discovering and developing a new drug, especially for use in livestock, is reflected in the limited number of new classes of antiparasitic agent launched on the market. New strategies are being adopted to minimise the cost of discovering potential drug candidates by maximising the chance of identifying a useful target mechanism of action and by speeding the time to discover and optimise a lead structure. These rely heavily on new technologies in target identification, screen development and lead optimisation. Examples of these will be discussed and speculation made about the possible factors that could influence the future shape of antiparasitic control.

Identification of a 4-fluorobenzyl l-valinate amide benzoxaborole (AN11736) as a potential development candidate for the treatment of Animal African Trypanosomiasis (AAT)

Graphical abstract