• Molecules and Cells
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• 제28권5호
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• pp.447-453
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• 2009

The quorum sensing (QS) inhibitors that antagonize TraR, a receptor protein for N-3-oxo-octanoyl-L-homoserine lactones (3-oxo-C8-HSL), a QS signal of Agrobacterium tumefaciens were developed. The structural analogues of 3-oxo-C8-HSL were designed by in silico molecular modeling using SYBYL packages, and synthesized by the solid phase organic synthesis (SPOS) method, where the carboxamide bond of 3-oxo-C8-HSL was replaced with a nicotinamide or a sulfonamide bond to make derivatives of N-nicotinyl-L-homoserine lactones or N-sulfonyl-L-homoserine lactones. The in vivo inhibitory activities of these compounds against QS signaling were assayed using reporter systems and compared with the estimated binding energies from the modeling study. This comparison showed fairly good correlation, suggesting that the in silico interpretation of ligand-receptor structures can be a valuable tool for the pre-design of better competitive inhibitors. In addition, these inhibitors also showed anti-biofilm activities against Pseudomonas aeruginosa.

• 대한화장품학회지
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• 제10권1호
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• pp.49-74
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• 1984

Rheology of gels prepared with stearyl dimethyl benzyl ammonium hectorite (SDBAH) and various polar additives in n-butyl acetate was investigated by measuring the viscosity and rheogram. Including generally recognized polar additives, additional studies on the rheogram and viscosity were made with ether-type methyl cellosolve and carbitol, with dimethyl sulfoxide (DMSO) having sulfonyl group, and furthermore with above-mentioned polar additives containing small quantity of water, It was observed that molecular size, dipole moments and dielectric constants of polar additives had a great influence on viscosity increase and rheology of SDBAH gel, and the increase of SDBAH interlayer spacing was important factor in gel formation and viscosity change. It was also shown that thixotropy effect was increased with the increase of polar additive concentration, finally changed to rheopexy from thixotropy as the concentration of polar additives was increased more than about 40% of SDBAH weight. In addition thixotropy changed to rheopexy as the increase of shear rate. It was further found that the aqueous solutions of polar additives (water content, 5-25%) had more effects on rheology than additives without water, and particularly 95clo DMSO solution was the most effective. And the optimum concentration of polar additives showing maximum viscosity in the same SDBAH concentration system was examined.

• 약학회지
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• 제33권6호
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• pp.350-360
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• 1989

The conformation and activity of the four benzenesulfonyl analogues of 4-aminobenzene-sulfonamide, 4-aminobenzenesulfonic acid, 4-methylbenzenesulfonamide, and 4-methylbenzenesulfonic acid with antibacterial activity on Staphylococcus aureus were studied using an empirical potential function (ECEPP/2) and the hydration shell model. The conformational energies were minimized from the starting conformations which included possible combinations of torsion angles in each molecule. To understand the hydration effect on the conformation of the molecule in aqueous solution, the hydration free energy of each group was calculated and compared each other. The conformational entropies of low-free-energy coformation of benzenesulfonly analogues were computed by a harmonic approximation. From the correlation of lowest-free-energy conformation of each compound and its antibacterial activity, it was found that the hydration of sulfonyl groups and the substituents are the decisive factors to show antibacterial activities.

• Archives of Pharmacal Research
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• 제10권4호
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• pp.239-244
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• 1987

An efficient and inexpensive method for the substitution of allylic hydroxyl group with fluoride, without allylic rearrangement, and elimination was developed. This method consists of treating an allylic alcohol with methylithium, followed by p-toluene sulfonyl fluoride, lithium fluoride and 12-Crown-4. This methodology was proved to be efficient by preparting geranyl fluoride, neryl fluoride, cinnamyl fluoride, E, E-farnesyl fluoride, retinyl fluoride and 4-fluoro-2-methyl-6-(ptolyl)-2-heptene.

• 대한화학회지
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• 제68권2호
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• pp.74-81
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• 2024

A sulfonic acid-water-silanol system in SO₃H-functionalized MCM-41 was investigated using solid-state nuclear magnetic resonance techniques. The proton exchange rate between a water molecule and a silanol group in the S-PE-MCM-41 was determined by analyzing the 1D proton spectra, the proton EXSY spectrum, and ²H spin-lattice relaxation data under various hydration levels. Two kinds of water-bounding sites were found in the S-PE-MCM-41: weakly and strongly bound sites. Over several hours, water molecules bound to the weakly bound sites at the low hydration level migrated to the strongly bound sites. At high temperature, the S-PE-MCM-41 easily lost water molecules weakly bound to the silanol, while the strongly bound water molecules survived. Water molecules that participated in the hydration of the phenethyl sulfonate were involved in the hydrogenbonded silanol mechanism of proton conductivity. This phenomenon contributes higher proton conductivity to the S-PE-MCM-41 by the cooperation of sulfonyl and silanol groups in the proton transfer process, even at higher temperature.

• Bulletin of the Korean Chemical Society
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• 제20권8호
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• pp.948-952
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• 1999

Electrophilic substitutions on β-position of 2,5-dimethyl pyrrole have been investigated theoretically. The electron donating methyl groups enrich electron densities on C-3, C-4 positions and π* interactions with methyl groups substituted on C-2 and C-5 positions pushed up the HOMO level of the pyrroles consequently induce rapid substitutions on C-3, C-4 sites. Substitution of phenylsulfonyl group on nitrogen stabilized LUMO levels through weak π bonding interactions. Unexpected deoxidation reaction underwent on the sulfonyl group substituted at C-3 position. The structures were solved by X-ray crystallography. Meanwhile, gas phase HF/6-31G* and density functional method (B3LYP/6-31G*) calculations gave favorable energies for 1-phenylsulfinyl pyrrole (6) over 3-phenylsulfinyl pyrrole (5) by 3.6-4.7 kcal/mol which is contrary to the experimental result. However the methods involve the effects of molecular polarizability and solvent, molecular dynamics (MD) and ab-initio self consistent reaction field (SCRF) calculations showed same trend as experiments. According to MD calculations, compound 5 is more stable than compound 6 by 4.15 kcal/mol and the SCRF, HF/6-31G* calculations gave more stable energy value for structure 5 than 6 by 0.03 kcal/mol.

• Bulletin of the Korean Chemical Society
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• 제15권6호
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• pp.473-477
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• 1994

Second-order rate constants have been measured spectrophotometrically for the nucleophilic substitution reactions of aryl substituted benzenesulfonates $(1,\;X-C_6H_4SO_2-OC_6H_4-Y)$ with aryloxides $(Z-C_6H_4O^{-})$ and ethoxide $(EtO^-)$ in absolute ethanol at $25^{circ}C$. The nucleophilicity of aryloxides increases with increasing electron donating ability of the substituent (Z) on aryloxides, and results in a good Hammett correlation with $\sigma^{-}$ constant. The reactivity of 1 toward aryloxides and ethoxide shows also significant dependence on the electronic nature of the substituent X and Y. Large positive ${\sigma}_{acyl}$ values have been obtained for the reaction of 1 with phenoxide and ethoxide, indicating that the leaving group departure is little advanced at the transition-state of the rate-determining step. This has been further supported from the fact that ${\sigma}^-$ constant gives extremely poor Hammett correlation, while ${\sigma}^0$ does reasonably good correlation for the reaction of 1 with ethoxide. Thus, the present sulfonyl-transfer reaction is proposed to proceed via a ratedetermining attack of nucleophile to the sulfur atom of 1 followed by a fast leaving group departure.

• 공업화학
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• 제10권1호
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• pp.124-128
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• 1999

개별적인 반응성이 알려진 니트로기와 벤질술포닐기가 벤젠 고리 위에서 서로 인접하여 위치할 때 광반응성에 미치는 상호 작용에 대해서 연구하고자 하였다. 니트로기를 포함하는 술포닐 에스테르(cyclohexyl 및 phenyl 2-nitro-${\alpha}$-toluenesulfonate)와 슬포닐아미드(시클로헥실, 페닐, 벤질, 및 피페리딜 2-nitro-${\alpha}$-toluenesulfonamide)의 용액 중 광반응 생성물로부터 벤질술포닐기와 그 ortho 위치에 존재하는 니트로기가 광반응시 서로 상승작용을 하지 않는다는 것을 알 수 있었다. 용액상의 광반응은 이어 필름 상에서의 광반응으로 확인 및 응용되었다. 즉, 두 가지의 2-nitro-${\alpha}$-toluensulfonamide를 포함한 poly(methacrylonitrile)(PMAN) 박막을 NaCl 판 위에 입히고 여기에 254 nm 자외선을 쪼이면서 관찰된 필름의 IR 스펙트럼의 변화로부터도 용액상의 광반응을 일부 확인하였으며 정량실험도 실시하였다. 또한, 본 용액실험의 결과인 광화학적 아민 발생은 poly(glycidyl methacrylate)를 이용한 상 발생 실험에 응용되어 성공적으로 광화학적 에폭시 가교를 수행할 수 있었다.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2005년도 BIOINFO 2005
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• pp.249-255
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• 2005

Angiotensin-converting enzyme (ACE) is primarily responsible for human hypertension. Current ACE drugs show serious cough and angiodema health problems due to the un-specific activity of the drug to ACE protein. The availability of ACE crystal structure (1UZF) provided the plausible biological orientation of inhibitors to ACE active site (C-domain). Three-dimensional quantitative structure-activity relationship (3D-QSAR) models have been constructed using the comparative molecula. field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) for a series of 28 ACE inhibitors. Alignment for CoMFA obtained by docking ligands to 1UZF protein using FlexX program showed better statistical model as compared to superposition of corresponding atoms. The statistical parameters indicate reasonable models for both CoMFA (q$^2$ = 0.530, r$^2$ = 0.998) and CoMSIA (q$^2$= 0.518, r$^2$ = 0.990). The 3D-QSAR analyses provide valuable information for the design of ACE inhibitors with potent activity towards C-domain of ACE. The group substitutions involving the phenyl ring and carbon chain at the propionyl and sulfonyl moieties of captopril are essential for specific activity to ACE.

• Archives of Pharmacal Research
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• 제25권3호
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• pp.270-274
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• 2002

Chromatographic separation of the stem bark extract of Mitragyna stipulosa afforded triterpene derivatives ursolic acid (1), quinovic acid (2), quinivic acid $3-O-{\beta}-D-glucopyranoside$ (3, quinovin glycoside C), quinovic acid 3-O-[$(2-O-sulfo)-{\beta}-D-quinovopyranoside$] (4, zygophyloside D) and quinovic acid $3-O-{\beta}-D-quinovopyranosyl-27-O-{\beta}-D-glucopyranosyl$ ester (5, zygophyloside B). These five compounds were subjected to the cytotoxicity on MTT assay system. Compound 1 among tested showed the most potent cytotoxicity. Quinovic acid showed less potent cytotoxicity than ursolic acid and sugar linkages to 2 decreased the cytotoxicity. Compound 4 more potent than 3 with indicate that the sulfonyl group significantly enhances the activity. This indicates that the glycosidic linkage in ursane-type triterpenoids has mainly negative effect on cytotoxicity unlike in oleanane-type glycosides.