Development of a novel series of trialkoxyaryl derivatives as specific and competitive antagonists of platelet activating factor.

The synthesis and structure-activity relationship (SAR) analysis of a novel series of trialkoxyaryl derivatives, as specific and competitive inhibitors of platelet activating factor (PAF), are described. Molecular modeling comparisons of PAF with the known antagonists Ginkgolide B and L-652731 led to the selection of N-[2-[(3,4,5-trimethoxybenzoyl)oxy]ethyl]-N,N,N-trimethylammonium iodide (1) from the Wellcome registry of compounds and to the synthesis of the lead compound N-[2-[[4-(hexyloxy)-3,5-dimethoxybenzoyl]oxy]ethyl]-N,N,N- trimethylammonium iodide (3, pKb 5.43). Further SAR considerations directed the design to 2-(hexyloxy)-1,3-dimethoxy-5-[4-(4-methylthiazol-5-yl)butyl] benzene (38) (pKb 7.14), a novel, specific, and competitive inhibitor of the PAF receptor in rabbit-washed platelets.

The effects of a novel series of selective inhibitors of arachidonate 5-lipoxygenase on anaphylactic and inflammatory responses.

In conclusion, we have described a novel series of acetohydroxamic acids that are potent and selective inhibitors of arachidonate 5-lipoxygenase in vitro and in vivo. In addition, we have shown that these compounds attenuate "leukotriene-dependent" anaphylactic bronchospasm, the accumulation of inflammatory leukocytes, and the development of fever in experimental models. It now remains to be determined if these compounds have any therapeutic value in man.

5-(Hydroxyimino)-4-methoxy-2-(pivaloylimino)thiazolidine-3 -acetamide, a reduced nitroheterocyclic derivative with potent schistosomicidal properties.

The synthesis and antischistosome properties of 5-(hydroxyimino)-4-methoxy-2-(pivaloylimino)thiazolidine-3- acetamide (1) are described. The compound was prepared by reduction of the nitrothiazoline (2) with stannous chloride in methanol, and represents the first example of a reduced nitroheterocyclic compound showing potent schistosomicidal properties. The possible relationship of compounds such as 1 to the as yet unidentified reduced active but toxic entities formed in vivo from nitroheterocyclics like metronidazole is discussed.

The efficacy of a novel compound, (e)-1-(4'-bromo-4-biphenylyl)-1-(4-chlorophenyl)-3-dimethylaminoprop-1-ene against Trypanosoma cruzi in mice.

The biological properties of a novel compound 353C with high activity against Trypanosoma cruzi, are described. The compound was about 10 times and 20 times more effective than either benznidazole or nifurtimox respectively, in producing radical cure in mice. 353C has a long half-life and showed anti-trypanosomal properties when given to mice at weekly intervals.

Antischistosomal effects of 5-(2,4,5-trichlorophenyl)hydantoin and related compounds.

5-(2,4,5-Trichlorophenyl)hydantoin and several analogues effected an 80-90% reduction of live schistosomes in infected mice at doses ranging from 265 to 329 mg/kg per day when administered orally in the diet for 14 days. The sodium salt of 5-(2,4,5-trichlorophenyl)hydantoin, when given by gavage to rhesus monkeys infected with Schistosoma mansoni at 200 mg/kg/day for 5 or 10 days, removed all but a few live worms with no evidence of intolerance.