- 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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