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In vitro bioassay screening of 346 methanol extracts originated from 281 native and cultivated plant species growing in Egypt, and related to 81 families, was carried out for schistosomicidal activity. The extracts were bioassayed at 100 mg=mL on viable Schistosoma mansoni mature worms in culture medium. Viability of worms was examined after exposure for 24 h, and mortality determined. Negative (DMSO) and positive (praziquantel) controls were used. Of the tested plant extracts, 72 were found to possess reproducible in vitro antischistosomal activity. These active extracts were further subjected to determination of their LC 50

A series of benzothiazol-2-yl-dithiocarbamates 3a-d along with their copper complexes 4a-c were synthesized via the reaction of suitable alkyl, aralkyl or heteroaryl halides with the sodium salt of benzothiazol-2-yl-dithiocarbamic acid, followed by complexation with copper sulphate. N-(4-Acetyl-5-aryl-4,5-dihydro-1,3,4-thiadiazol-2-yl)-N-benzothiazol-2-yl-acetamides 7a-c were synthesized by cyclization of the appropriate thiosemicarbazones 6a-c in acetic anhydride. Selected compounds were screened for in vitro schistosomicidal activity against Schistosoma mansoni at three different dosage levels (10, 50 and 100 μg/ mL). Three of these products, 4a-c, showed schistosomicidal activity similar to praziquantel, with 100% worm mortality at 10 μg/mL. These compounds would constitute a new class of potent schistosomicidal agents.

These species may represent additional natural sources of bioactive material that deserve further investigation for drug discovery against schistosomiasis.

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Abstract4-Benzylidene-2-phenyl-5(4H)-oxazolones react with Wittig-Horner reagents in the presence of alcoholic sodium alkoxide to give novel dioxopyrrolidinephosphonates, diethyl [3-(benzoylamino)- 1-cyano-2-oxo-4-phenylbut-3-en-1-yl]phosphonate and phosphonoalkenoate derivatives. Both the phosphonate adducts and the ester products were also isolated from the reaction of oxazolones with triethyl phosphonoacetate using alcoholic sodium ethoxide and/or sodium hydride as a base. Possible reaction mechanisms are considered, and the structural assignments are based on analytical and spectroscopic results. The biological evaluation of the new compounds is reported.

Organo-phosphorus compounds S 0080 Reactions of 5(4H)-Oxazolones with Wittig-Horner Reagents: Novel Synthesis of Dioxopyrrolidinephosphonates and Phosphonoalkanoates with AnticipatedSchistosomicidal Activity. -Compound (III) exhibits strong antischistosomal activity. -(BOULOS*, L. S.; ARSANIOUS, M. H. N.; EWIES, E. F.; RAMZY, F.; Z.