- Discovery and preliminary evaluation of 2-aminobenzamide and hydroxamate derivatives containing 1,2,4-oxadiazole moiety as potent histone deacetylase inhibitors
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Using Entinostat as a lead compound, 2-aminobenzamide and hydroxamate derivatives have been designed and synthesized. The entire target compounds were investigated for their in vitro antiproliferative activities using the MTT-based assay against five human cancer cell lines including U937, A549, NCI-H661, MDA-MB-231 and HCT116. 2-Aminobenzamide series of compounds (10a-10j) demonstrated the most significant inhibition against human acute monocytic myeloid leukemia cell line U937, but no or poor activities against two human lung cancer cell lines. Furthermore, the target compounds were screened for their inhibitory activities against HDAC 1, 2, and 8. 2-Aminobenzamide derivatives (10) manifested a higher selectivity for HDAC 1 over HDAC 2, but were not active against HDAC 8. In contrast, most hydroxamate derivatives (11) inhibit HDAC 8 with lower IC50 values than SAHA and Entinostat. Docking study with selected compounds 10f and 11a revealed that the compounds might bind tightly to the binding pockets in HDAC 2 and HDAC 8, respectively. The results suggest that they may be promising lead compounds for the development of novel anti-tumor drug potentially via inhibiting HDACs.
- Cai, Jin,Wei, Hongtao,Hong, Kwon Ho,Wu, Xiaoqing,Cao, Meng,Zong, Xi,Li, Lushen,Sun, Chunlong,Chen, Junqing,Ji, Min
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- Novel 1,3-dipropyl-8-(1-heteroarylmethyl-1H-pyrazol-4-yl)-xanthine derivatives as high affinity and selective A2B adenosine receptor antagonists
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A series of new 1,3-dipropyl-8-(1-heteroarylmethyl-1H-pyrazol-4-yl)- xanthine derivatives as A2B-AdoR antagonists have been synthesized and evaluated for their binding affinities for the A2B, A 1, A2A, and A3-AdoRs. 8-(1-((3-phenyl-1,2,4- oxadiazol-5-yl)methyl)-1H-pyrazol-4-yl)-1,3-dipropyl-1H-purine-2,6(3H,7H)-dione (4) displayed high affinity (Ki = 1 nM) and selectivity for the A2B-AdoR versus A1, A2A, and A 3-AdoRs (A1/A2B, A2A/A2B, and A3/A2B selectivity ratios of 370, 1100, and 480, respectively). The synthesis and SAR of this novel class of compounds are presented herein.
- Elzein, Elfatih,Kalla, Rao,Li, Xiaofen,Perry, Thao,Parkhill, Eric,Palle, Venkata,Varkhedkar, Vaibahv,Gimbel, Art,Zeng, Dewan,Lustig, David,Leung, Kwan,Zablocki, Jeff
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p. 302 - 306
(2007/10/03)
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- The discovery of a selective, high affinity A2B adenosine receptor antagonist for the potential treatment of asthma
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Adenosine has been suggested to play a role in asthma, possibly via activation of A2B adenosine receptors on mast cells and other pulmonary cells. We describe our initial efforts to discover a xanthine based selective A2B AdoR antagonist that resulted in the discovery of CVT-5440, a high affinity A2B AdoR antagonist with good selectivity (A2B AdoR Ki = 50 nM, selectivity A1 > 200: A2A > 200: A3 > 167).
- Zablocki, Jeff,Kalla, Rao,Perry, Thao,Palle, Venkata,Varkhedkar, Vaibhav,Xiao, Dengming,Piscopio, Anthony,Maa, Tenning,Gimbel, Art,Hao, Jia,Chu, Nancy,Leung, Kwan,Zeng, Dewan
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p. 609 - 612
(2007/10/03)
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- Antikinetoplastid activity of 3-aryl-5-thiocyanatomethyl-1,2,4-oxadiazoles
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A series of 5-thiocyanatomethyl- and 5-alkyl-3-aryl-1,2,4-oxadiazoles were synthesized and evaluated for their activity against kinetoplastid parasites. Formation of the oxadiazole ring was accomplished through the reaction of benzamidoximes with acyl chlorides, while the thiocyanate group was inserted by reacting the appropriate 5-halomethyl oxadiazole with ammonium thiocyanate. The thiocyanate-containing compounds possessed low micromolar activity against Leishmania donovani and Trypanosoma brucei, while the 5-alkyl oxadiazoles were less active against these parasites. 3-(4-Chlorophenyl)-5-(thiocyanatomethyl)-1, 2,4-oxadiazole (compound 4b) displayed modest selectivity for L. donovani axenic amastigote-like parasites over J774 macrophages, PC3 prostate cancer cells, and Vero cells (6.4-fold, 3.8-fold, and 9.1-fold, respectively), while 3-(3,4-dichlorophenyl)-5-(thiocyanatomethyl)-1,2,4-oxadiazole (compound 4h) showed 30-fold selectivity against Vero cells but was not selective against PC3 cells. In a murine model of visceral leishmaniasis, compound 4b decreased liver parasitemia caused by L. donovani by 48% when given in five daily i.v. doses at 5mg/kg and by 61% when administered orally for 5days at 50mg/kg. These results indicate that aromatic thiocyanates hold promise for the treatment of leishmanial infections if the selectivity of these compounds can be improved.
- Cottrell, Denise M.,Capers, Jeffrey,Salem, Manar M.,DeLuca-Fradley, Kate,Croft, Simon L.,Werbovetz, Karl A.
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p. 2815 - 2824
(2007/10/03)
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- Potent, orally active aldose reductase inhibitors related to zopolrestat: Surrogates for benzothiazole side chain
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A broad structure-activity program was undertaken in search of effective surrogates for the key benzothiazole side chain of the potent aldose reductase inhibitor, zopolrestat (1). A structure-driven approach was pursued, which spanned exploration of three areas: (1) 5/6 fused heterocycles such as benzoxazole, benzothiophene, benzofuran, and imidazopyridine; (2) 5- membered heterocycles, including oxadiazole, oxazole, thiazole, and thiadiazole, with pendant aryl groups, and (3) thioanilide as a formal equivalent of benzothiazole. Several benzoxazole- and 1,2,4-oxadiazole- derived analogues were found to be potent inhibitors of aldose reductase from human placenta and were orally active in preventing sorbitol accumulation in rat sciatic nerve, in an acute test of diabetic complications. 3,4-Dihydro-4- oxo-3-[(5,7-difluoro-2-benzoxazolyl)methyl]-1-phthalazineacetic acid (124) was the best of the benzoxazole series (IC50 = 3.2 x 10-9 M); it suppressed accumulation of sorbitol in rat sciatic nerve by 78% at an oral dose of 10 mg/kg. Compound 139, 3,4-dihydro-4-oxo-3-[[(2-fluorophenyl)-1,2,4- oxadiazol-5-yl]methyl]-1-phthalazineacetic acid, with IC50 -8 M, caused a 69% reduction in sorbitol accumulation in rat sciatic nerve at an oral dose of 25 mg/kg. The thioanilide side chain featured in 3-[2-[[3- (trifluoromethyl)phenyl]amino]-2-thioxoethyl]-3,4-dihydro-4-oxo-1- phthalazineacetic acid (195) proved to be an effective surrogate for benzothiazole. Compound 195 was highly potent in vitro (IC50 = 5.2 x 10-8 M) but did not show oral activity when tested at 100 mg/kg. Additional structure-activity relationships encompassing a variety of heterocyclic side chains are discussed.
- Mylari,Beyer,Scott,Aldinger,Dee,Siegel,Zembrowski
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p. 457 - 465
(2007/10/02)
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