- Identification of diphenylalkylisoxazol-5-amine scaffold as novel activator of cardiac myosin
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To identify novel potent cardiac myosin activator, a series of diphenylalkylisoxazol-5-amine compounds 4–7 have been synthesized and evaluated for cardiac myosin ATPase activation. Among the 37 compounds, 4a (CMA at 10 μM = 81.6%), 4w (CMA at 10 μM = 71.2%) and 6b (CMA at 10 μM = 67.4%) showed potent cardiac myosin activation at a single concentration of 10 μM. These results suggested that the introduction of the amino-isoxazole ring as a bioisostere for urea group is acceptable for the cardiac myosin activation. Additional structure–activity relationship (SAR) studies were conducted. Para substitution (-Cl, –OCH3, -SO2N(CH3)2) to the phenyl rings or replacement of a phenyl ring with a heterocycle (pyridine, piperidine and tetrahydropyran) appeared to attenuate cardiac myosin activation at 10 μM. Additional hydrogen bonding acceptor next to the amino group of the isoxazoles did not enhance the activity. The potent isoxazole compounds showed selectivity for cardiac myosin activation over skeletal and smooth muscle myosin, and therefore these potent and selective isoxazole compounds could be considered as a new series of cardiac myosin ATPase activators for the treatment of systolic heart failure.
- Boggu, Pulla Reddy,Venkateswararao, Eeda,Manickam, Manoj,Sharma, Niti,Kang, Jong Seong,Jung, Sang-Hun
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- QUINOLINE DERIVATIVES
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The invention concerns quinoline derivatives of Formula (I): or a pharmaceutically-acceptable salt thereof, wherein each of X1, p, R1, q, R2, R3, R4, R5, Ring A, r and R6 has any of the meanings defined hereinbefore in the description; processes for their preparation, pharmaceutical compositions containing them and their use in the manufacture of a medicament for use in the treatment of cell proliferative disorders.
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Page/Page column 166
(2008/06/13)
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- Synthesis and anticonvulsant activity of enaminones. 4. Investigations on isoxazole derivatives
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Due to the exceptional anticonvulsant activity displayed by substituted aniline enaminones, related pyridine derivatives and phenothiazines synthesised in our laboratories, the further investigation of various aromatic heterocycles was undertaken. Condensation of cyclic 1,3-diketo esters with 3-, and 5-aminoisoxazole derivatives led to a series of potent anti-maximal electroshock (MES) analogues, three of which occurred in the 3-amino series: ethyl ester (10), orally (po) active in rats [ED50 68.9 mg kg-1, TD50>500 mg kg-1, protective index (PI=TD50/ED50)>49.6]; methyl ester (9), ED50 68.9 mg kg-1 intraperitoneally (ip) in mice, TD50>500 mg kg-1, PI>7.3, and tert-butyl ester (8), ED50 28.1 mg kg-1 po in rats, TD50>500 mg kg-1, PI>17.8. Sodium channel binding studies, as well as evaluations against pentylenetetrazol, bicuculline, and picrotoxin on isoxazole 10 were all negative, leading to an unknown mechanism of action. X-ray diffraction patterns of a representative of the 3-amino series (isoxazoles 6-11) unequivocally display the existence of intramolecular hydrogen bonding of the nitrogen to the vinylic proton in the cyclohexene ring, providing a pseudo three ring structure which was also shown previously with the vinylic benzamides. Physicochemical-permeability across the BBB suggested an efflux mechanism for the previously synthesised aniline enaminones, but not with isoxazole 10.
- Eddington, Natalie D,Cox, Donna S,Roberts, Ralph R,Butcher, Raymond J,Edafiogho, Ivan O,Stables, James P,Cooke, Neville,Goodwin, Angela M,Smith, Carlynn A,Scott
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p. 635 - 648
(2007/10/03)
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