butylstannane in benzene (1.62 or 3.24 M), and the solutions were degassed, heated at 80 O C for 3 h, and then analyzed for 11 and 12 by GC. The results are given in the text.Reaction of 8 with Tributylstannane. The bromide 8 (10.2 mg, 0.046 mmol) was dissolved in benzene (2.0 mL). Tributylstannane (6.2 pL, 0.023 mmol) and a trace of AIBN were added to an aliquot (0.50 mL) of this solution, which was then heated in a sealed tube at 80 O C for 17 h. After distillation (bath 60 O C (50 mm)), the mixture was analyzed by GC-MS analysis (40 O C isothermal). Varying amounts of tributylstannane were added to other aliquota, which were then heated and analyzed in the same way for 11 and 12. Within experimental error the results obtained were the same as those from reactions of 5. Registry No. HO(CH,),CH(t-BU)(CH~)~CO~M~, 135561-19-2; MeP(Ph)3+.Br-, 1779-49-3; H2C=CHCH2CH(t-Bu)(CH2)2C02Me, 135561-20-5; H02C-(CH2)2CH(t-Bu)CH2C02H, , O~NCBH~COC~, 122-04-3; o-O~NCBHIC(O)O(CH~)~CH(~~U)-(CH2)2OH, 135561-21-6; o-O~NCBHIC(O)O(CH~)~CH(~-BU)-CH,CHO, 135561-22-7; H~C=CHCH~CH(~-BU)CH~C(O)-OC&N02-p, 135561-23-8; N-hydroxypyridine-2-thione, sodium salt, 15922-78-8; 3-tert-butylcyclopentanone, 5581-94-2; l-tertbutyl-3-methylenecyclopentane, 69217-81-8. Supplementary Material Available: Experimental proce-7, 8, intermediates between 6 and 7; and the 0.60.95 ppm region of the " z 1~spectrum of a 32 mixture of cisand trau-12 (9 pages). Ordering information is given on any

Heparanase is the sole mammalian enzyme capable of cleaving glycosaminoglycan heparan sulfate side chains of heparan sulfate proteoglycans. Its altered activity is intimately associated with tumor growth, angiogenesis, and metastasis. Thus, its implication in cancer progression makes it an attractive target in anticancer therapy. Herein, we describe the design, synthesis, and biological evaluation of new benzazoles as heparanase inhibitors. Most of the designed derivatives were active at micromolar or submicromolar concentration, and the most promising compounds are fluorinated and/or amino acids derivatives 13a, 14d, and 15 that showed IC 0.16-0.82 μM. Molecular docking studies were performed to rationalize their interaction with the enzyme catalytic site. Importantly, invasion assay confirmed the antimetastatic potential of compounds 14d and 15. Consistently with its ability to inhibit heparanase, compound 15 proved to decrease expression of genes encoding for proangiogenic factors such as MMP-9, VEGF, and FGFs in tumor cells.

Heparanase is the only mammalian endo-β-D-glucuronidase involved in a variety of major diseases. The upregulation of heparanase expression increases tumor size, angiogenesis, and metastasis, representing a validated target in the anti-cancer field. To date, only a few small-molecule inhibitors have been described, but none have gotten through pre-clinical development. Previously, we explored 2-(4-(4-(bromo-methoxybenzamido)benzylamino)phenyl) benzazole derivatives as antiheparanase agents, proposing this scaffold for development of broadly effective heparanase inhibitors. Herein, we report an extended investigation of new symmetrical 2-aminophenyl-benzazolyl-5-acetate derivatives, proving that symmetrical compounds are more effective than asymmetrical analogues, with the most-potent compound, 7g, being active at nanomolar concentration against heparanase. Molecular docking studies were performed on the best-acting compounds 5c and 7g to rationalize their interaction with the enzyme. Moreover, invasion assay confirmed the anti-metastatic potential of compounds 5c, 7a, and 7g, proving the inhibition of the expression of proangiogenic factors in tumor cells.