1. Samir M. El-Moghazy, Nahed M. Eid, Sahar M. Abou-Seri and Shaimaa M. Abdel-Rahman * Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Cairo University 1- Introduction and Aim 2- Chemistry Compounds incorporating heterocyclic ring systems continue to attract considerable interest due to the wide range of biological activities they posses. Five membered heterocycles like isoxazoline and pyrazoline are well acknowledged to possess a wide range of anticancer activities e.g. 5-(4-substituted phenyl)-3-(3,4,5-trimethoxyphenyl)-4,5-dihydro-1H-pyrazole I which are potent antitumor agents act via inhibition of tubulin polymerization. 1,2 In the present study new series of isoxazoline 4a-b, pyrazoline 5a - b and 7a-f derivatives have been designed via structural modification of the lead compound I (Figure 1). They are synthesized via Claisen-Schmidt condensation followed by cyclizations with hydroxylamine HCl and hydrazine hydrate under the appropriate conditions. 3- Biological Evaluation Several isoxazoline and pyrazoline derivatives were synthesized. Some of the new target compounds were subjected to antitumor screening against different cell lines in NCI, Maryland, U.S.A. The results showed that compound 4a displayed the highest antitumor activity against almost all cell lines while compound 7c displayed a potential antitumor activity against leukemia (SR) and colon (HT-29) cell lines. 4- Conclusion 5- References Screening of antitumor activity of some selected compounds against a panel of 60 cell lines in a dose of 10 uM was performed in NCI ( Table 1). 1.Cenzo, C., Valentina, O., Loredana, V., Massimo, C. and Claudio, P.; Bioorg. Med. Chem. 2010, 18, 6238- 6248. 2.Julia, K., Renee, P., Daniele, C., Alain, C., Claude, M. and Jean-Claude, F.; Bioorg. Med. Chem. 2006, 14, 4067-4077. Cell lines 4a5a7a7b7c7d Leukemia CCRF-CEM HL-60(TB) K-562 MOLT-4 RPMI-8226 SR 4.22 -22.49 5.35 12.44 7.17 12.94 -- 68.60 -- nt -- 66.21 -- 72.41 54.31 nt -56.52 44.01 61.92 -14.62 -- nt -- 64.41 -- 62.48 Non small cell lung cancer A549/ATCC HOP-62 HOP-92 NCI-H226 NCI-H23 NCI-H322M NCI-H460 NCI-H522 33.23 20.26 nt 66.81 nt 39.76 10.15 -10.57 -- nt -- nt -- nt -- nt -- 60.12 -- Colon cancer COLO 205 HCC-2998 HCT-116 HCT-15 HT29 KM12 SW-620 0.63 50.40 23.27 25.80 3.11 28.29 21.71 -- 64.47 62.94 21.28 -- CNS cancer SF-268 SF-295 SF-539 SNB-19 SNB-75 U251 48.92 -6.41 -18.67 59.57 6.51 24.34 -- Melanoma LOX IMVI MALME-3M M14 MDA-MB-435 SK-MEL-2 SK-MEL-28 SK-MEL-5 UACC-257 UACC-62 42.40 nt 26.42 -71.92 -10.86 66.15 nt 32.59 46.51 -- nt -- nt -- nt -- nt -- Ovarian cancer IGORV1 OVCAR-3 OVCAR-4 OVCAR-5 OVCAR-8 NCI/ADR-RES SK-OV-3 44.71 17.48 -- 72.23 31.52 14.75 17.54 -- nt -- nt -- nt -- Renal cancer 786-0 A498 ACHN CAKI-1 RXF 393 SN12C TK-10 UO-31 32.42 -4.69 51.17 19.14 4.72 46.46 nt 36.24 -- nt -- nt -- nt -- nt -- 66.66 -- 70.64 -- nt -- 70.85 Prostate cancer PC-3 DU-145 26.25 22.78 -- 70.21 -- Breast cancer MCF7 MDA-MB-231/ATCC HS 578T BT-549 T-47D MDA-MB-468 13.95 59.75 19.00 27.69 nt -- nt -- nt -- 71.15 -- SYNTHESIS AND IN VITRO ANTITUMOR ACTIVITY OF NEW 5-FURANOISOXAZOLINE AND 5-FURANOPYRAZOLINE DERIVATIVES Table 1 shows the percentage growth in each cell line