• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.20-26
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• 2014

The interaction of p-halogenated phenol derivatives with the micellar system of tetradecyltrimethylammonium bromide (TTAB) was studied by the UV/Vis spectrophotometric method. Effects of substituents, additives, and temperatures on the solubilization of phenol derivatives have been measured. The results show that all the values of ${\Delta}G^o$ and ${\Delta}H^o$ were negative and the values of ${\Delta}S^o$ were positive for all phenol derivatives within the measured temperature range. The calculated thermodynamic parameters depended on the size, the electro-negativity, and the hydrophobic property of halogen substituents. The addition of n-butanol results in the decrement in tthe Ks values and the addition of NaCl caused the increment in the Ks values for all the phenol derivatives. From these changes we can postulate that the solubilization sites of the phenol derivatives in the micelle depend severely on properties of the halogen-substituent.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.395-400
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• 2001

The effects of ortho- (R = H and CH3) and Y-substituents (Y = OCH3, CH3H and CN), which are directly attached to the carbonyl carbon, on the protonation equilibria of the para-X-substituted benzoyl derivatives, 4-X -2, 6-di-R-C6H2-C(=O)-Y, are investigated theoretically using the B3LYP method with 6-31+G* basis set. Structurally, both of the (B) and (BH+ ) forms in the species with R = H are nearly coplanar regardless of the Y-substituents implying that the steric repulsion between Y-substituent and R = H is relatively small. In the species with R = CH3 , the tortional angle (Θ) between the carbonyl moiety and aryl ring varies from zero to near right angle depending on the degree of steric repulsion between Y and R = CH3 and the resonance demand. However the reaction energies, ΔG°, for the protonation processes are more favorable for R = CH3 than for R = H due to stronger electron donating effect of R = CH3 , although the species with R = CH3 are unfavorable sterically. On the other hand, the Hammett type plots are progressively better correlated with б+ than with б values on going from Y = OCH3 to Y = CN for both species with R = H and CH3 indicating that the degree of resonance delocalization between carbonyl moiety and X-substituent is increased for a more electron accepting Y-substituent. Nevertheless the effects of R = CH3 on the magnitude of Hammett type reaction constants ( б or б+ ) are not much different from those of R = H.

• Biomolecules & Therapeutics
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• v.31 no.2
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• pp.176-182
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• 2023

Among 14 subtypes of serotonin receptors (5-HTRs), 5-HT_2AR plays important roles in drug addiction and various psychiatric disorders. Agonists for 5-HT_2AR have been classified into three structural groups: phenethylamines, tryptamines, and ergolines. In this study, the structure-activity relationship (SAR) of phenethylamine and tryptamine derivatives for binding 5-HT_2AR was determined. In addition, functional and regulatory evaluation of selected compounds was conducted for extracellular signal-regulated kinases (ERKs) and receptor endocytosis. SAR studies showed that phenethylamines possessed higher affinity to 5-HT_2AR than tryptamines. In phenethylamines, two phenyl groups were attached to the carbon and nitrogen (R³ ) atoms of ethylamine, the backbone of phenethylamines. Alkyl or halogen groups on the phenyl ring attached to the β carbon exerted positive effects on the binding affinity when they were at para positions. Oxygen-containing groups attached to R³ exerted mixed influences depending on the position of their attachment. In tryptamine derivatives, tryptamine group was attached to the β carbon of ethylamine, and ally groups were attached to the nitrogen atom. Oxygen-containing substituents on large ring and alkyl substituents on the small ring of tryptamine groups exerted positive and negative influence on the affinity for 5-HT_2AR, respectively. Ally groups attached to the nitrogen atom of ethylamine exerted negative influences. Functional and regulatory activities of the tested compounds correlated with their affinity for 5-HT_2AR, suggesting their agonistic nature. In conclusion, this study provides information for designing novel ligands for 5-HT_2AR, which can be used to control psychiatric disorders and drug abuse.

• Archives of Pharmacal Research
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• v.12 no.2
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• pp.68-72
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• 1989

The hydrolysis rates of ester and amide derivatives of 20-dihydroprednisolonic acid were measured in rat serum and liver homogenate. The hydrolysis rate of the esters in serum was found to be faster than that in liver homogenate on the basis of blood volume and liver weight, while the amide derivatives showed much slower change. And it is also found that the size of substituents at C-21 and C-20 configuration expressed considerable effects on the hydrolysis rate of these derivatives.

• Archives of Pharmacal Research
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• v.12 no.2
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• pp.135-137
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• 1989

A convenient route is reported for the synthesis of certain series of 4H-thieno[2,3-b][1]benzothiopyran-4-ones, carrying various substituents at position 2 such as arylazomethines (7,8), thiazolidin-4-ones (9-13), ${\alpha},\;{\beta}-unsaturated$ ketones (16,17), 2-pyridones (19-23), tetrahydrothiophen-4-ones (24,28), and nitroalkenes (29,30), as potential schistosomicidal or antihistaminic agents.

• Archives of Pharmacal Research
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• v.23 no.1
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• pp.35-41
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• 2000

In order to investigate the stereochemical requirements of planar structure at 4-position of 4-phenyl-1-arylsulfonylimidazolidinones (1) for their cytoxicities against human cancer cell lines, the size, the distance from imidazolidinone ring, and the conformation of this moiety were variegated. Replacement of phenyl moiety with naphthyl in compounds 2 and 3 or benzyl moiety in compound 4 sharply reduced activity of 1. Conformational restriction on phenyl ring in compound 5 also resulted in the loss of activity of 1. Therefore, phenyl moiety without any substituents directly attached to imidazolidinone ring of 1 should be considered as an essential pharmacophore for this analog.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.04a
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• pp.120-122
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• 2008

Relationship between hydrophobicity of dyes and affinity onto pure polypropylene fibers has been analyzed by using the molecular descriptor as a method to predict chemical and physical characteristics of compounds. Hydrophobicity of newly synthesized red dyes calculated by LogP which is one of molecular descriptors was increased continuously as the length of alkyl substituents increased. The dyeability onto polypropylene fibers was increased as LogP of the dyes increased and was very high when the hydrophobicity is over 6.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.535-540
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• 2012

A series of benzamide-based histone deacetylases (HDACs) inhibitors possessing N-(aminopyridine) residue as the zinc binding site of HDAC were synthesized and evaluated. Among these derivatives, compounds with N-(2-amino-4-pyridine) benzamide moiety have been found as the most potent ones. Moreover, introduction of appropriate substituents on the terminal aryl group acting as the surface-recognition domain could significantly improve the antiproliferative activity. In particular, the compound 4k possessed favorable pharmacokinetic characteristics and exhibited potent antitumor activity on xenograft model in mice at well tolerated doses, thus suggesting a good therapeutic index.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1031-1037
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• 2006

New nickel complexes containing novel tetradentate ligands, 4,5-substituted-1,2-bis(pyridine-2-carboxamide)-benzene ligands but lacking alkyl or halide ligands in the coordination sphere have been prepared. They were activated with MMAO (modified methylaluminoxane) to be proven as efficient catalysts for the polymerization of norbornene. Both electron-donating and -withdrawing substituents on the benzene ring and polar solvents enhance the catalytic activity for olefin polymerization. Improvement in thermal stability of the complexes was observed. Some of these complexes were crystallographically determined to have square planar geometry. A plausible mechanism involving dissociation of ligands is proposed.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2960-2964
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• 2011

The efficient asymmetric hydrosilylation of imines in the presence of polymethylhydrosiloxane has been investigated by screening chiral diamine-zinc complexes. A series of chiral diamine ligands were prepared from optically pure 1,2-diphenyl-1,2-ethanediamine and screened for effectiveness. N-Benzylic substituents were required for high enantioselectivity; ligands with bulky groups or extra coordinating groups such as OH and S lowered the catalytic activity. The level of asymmetric induction was usually in >90% ee range for aromatic imine substrates. A linear correlation between the ee of the ligand and that of the product was observed, indicating the presence of a 1:1 ratio of ligand to metal coordination in the active catalytic complex.