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Some of the products show antitumor activity [e.g. (VIIa), (VIIb), (IIIa)]. Compound (IXb) possesses moderate in vitro anti-HIV activity and various derivatives exhibit promising antimicrobial effects. -(RIDA, S. M.; ASHOUR, F. A.; EL-HAWASH*, S. A. M.; EL-SEMARY, M. M.; BADR, M. H.; Arch.

In search of novel purine antimetabolites, a series of 8-substituted methylxanthine derivatives was prepared in order to explore their in vitro anticancer, anti-HIV-1 and antimicrobial activities. The target compounds include: 8-[(3-substituted-4-oxo-thiazolidin-2-ylidene)hydrazino]-1,3-dimethyl (or 1,3,7-trimethyl)-3,7-dihydropurine-2,6-diones 5a-e, 8-[(3,4-disubstituted 2,3-dihydrothiazol-2-ylidene)hydrazino]-1,3,7-trimethyl-3,7-dihydropurine-2,6-diones 6a-d and 8-(5-amino-3-arylpyrazol-1-yl)-1,3-dimethyl- (or 1,3,7-trimethyl)-3,7-dihydropurine-2,6-diones 7a-g. The in vitro anticancer results revealed that compound 5d exhibited a super sensitivity profile towards leukemia K-562 with a GI(50) value of <0.01 microM. Compound 7c showed significant activity against colon cancer HCT-15 and renal cancer CAKI-1 (GI(50) values of 0.47 and 0.78 microM, respectively). Compound 7a displayed high activity against colon cancer HCT-15 (GI(50 )= 0.8 microM). The anti-HIV-1 results indicated that compound 6b displayed a good reduction of viral cytopathic effect (56.69%). The antimicrobial results showed that compound 5a was four times more active than ampicillin against P. aerugenosa (MIC =or< 25 microg/mL), compound 5b had twice the activity of ampicillin, while compounds 5d, 7c and 7f were equipotent to ampicillin. On the other hand, compound 7a was equipotent to ampicillin against P. vulgaris (MIC = 50 microg/mL).

Synthesis and Antimicrobial Testing of Novel Oxadiazolylbenzimidazole Derivatives. -Some of the title compounds, e.g. (II) and (V), show weak antimicrobial activity. -(HABIB, N. S.; SOLIMAN, R.; ASHOUR, F. A.; EL-TAIEBI, M.; Pharmazie 52 (1997) 10, 746-749; Dep. Pharm. Chem., Fac. Pharm., Alexandria Univ., Alexandria 21521, Egypt; EN)