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성낙도 한국농화학회 1989 Applied Biological Chemistry (Appl Biol Chem) Vol.32 No.2
In order to seek the molecular basis of higher insecticidal activity of the carbamates with two methyl groups, m-xylyl-N-methylcarbamate(MXNMC) than the corresponding unsubstituted phenyl N-methylcarbamate(PNMC), these two derivatives have been studied by molecular orbital(MO) theoretically using extended Hu◎ckel theory(EHT), and analysis of regression and linear free energy relationship(LFER). The most stable stereo structure(Z,Z) shows that the phenyl group occupies vertical(θ=90°) position on the plane of the N-methylcarbamyl group. Regression analysis shows that especially good correlation exists between the pI_(50) values and the calculated MO quantities when the hydrogen atomic charge of metaposition and of m-methyl groups, and LUMO energy are taken as variables. The LFER analysis on the carbamylation indicates that field(F) effect(60%) is slightly larger than resonance(R) effect(40%) in PNMC(F$gt;R), whereas, in case of MXNMC, R effect(98.6%) is much larger than F effect(1.4%)(R≫F). From the basis on the findings, the enhancement of insecticidal activity of MXNMC may be the result of hyperconjugation by m-methyl groups.
Imidacloprid 와 그 유도체들의 살충활성에 미치는 3 - N - 치환기 ( R ) 의 영향
성낙도(Nack Do Sung),강문성(Moon Sung Kang),장해성(Hae Sung Jang),김대황(Dae Whang Kim) 한국응용생명화학회 1996 Applied Biological Chemistry (Appl Biol Chem) Vol.39 No.2
Imidacloprid and a series of the related compounds were synthesized, and influence of 3-N substituents(R) on the insecticidal activities against Brown plant hopper(Nilaparvata lugens) and Green peach aphid(Myzus persicae) were examined quantitatively from the structure-activities relationships(SAR) techniques. The results indicated that the molecular hydrophobicity(π) and inductive substituent constant(σ^*) of substituents(R) at 3-nitrogen position on the imidazolidine ring were important factors. Variations in the potency were parabolically related to the both constants. In case of Brown plant hopper, optimum value of π constant was 0.52, whereas the value of σ^* constant against Green peach aphid was 1.17, respectively. Among them, the strong electron withdrawing groups(σ^*$gt;0) such as methyl and benzenesulfonyl group(7 & 8) showed lower insecticidal activity and non-substituted, 1(imidacloprid) showed the best insecticidal activity. It seems that the intramolecular associated(H-bond) form between 2-N-nitro group and 3-imid group may contribute to the higher insecticidal activity to the both sucking insects. And in aqueous solution, 1 showed higher residual activity below pH 6.0, and the half-life(T_½) was about 6 month at pH 7.0 (ca. k_(obs) : 5×10^(-8) sec.^(-1)) and 45℃.
정량적인 구조-활성상관(QSAR) 기법에 의한 새로운 농약의 개발 I : Ⅳ.국내의 연구 동향과 전망
성낙도 충남대학교 형질전환복제돼지연구센터 2004 논문집 Vol. No.8
Biological Hammett Equation에 기초하여 H문초-Fujita식으로 제안된 정량적인 구조 활성상관(QSAK) 기법 (Sung, Nack-Do (2002) Development of new agrochemicals by quantitative structure-activity relationship(QSAR) methodology. Kor, J. Pestic. S챠. 6: 166-174, 231-243 및 7: 1-11)에 따른 새로운 농약의 탐색과 개발에 관련하여 1990년도를 전후한 국내에서 이루어진 QSAR기법중 주로 2D QSAR기법의 활용연구 현황에 대하여 조명하였다. It was reviewed for the status of domestic research before and after 1990's for search of a new pesticides using 2D QSAR of quantitative structure-activily relationship (QSAR) methodologies (Sung. Nack-Do (2002) Development of new agrochemicals by quantitative structure-activity relationship (QSAR) methodology. Kor. J Pestic. Sci. 6. 166-174, 231-243 & 7, 1-11) which was proposed according to Hansch-Fujita equation based on the concept of biological Hammett equation.
Docking and Virtual Screening Studies for New Leads of Boar Salivary Lipocalin
성낙도,박창식,박형연,김찬경 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.5
We have performed FlexX docking experiments to predict the best docking poses of 5-androst-16-en-3-ol or 5-androst-16-en-3-one to Boar salivary lipocalin (SAL). Since no steroids were found inside of the binding pocket of the X-ray structure of 1GM6, we tried to find docking structures after opening the pocket using the random tweak option implemented in SYBYL. This operation allowed the ligand to enter the pocket. The best poses generated from FlexX were different from the structures reported earlier, which calculated docking poses by manual docking followed by minimization. Analysis of docking poses allowed us to identify pharmacophores. From this information, virtual screening experiments using UNITY were performed. Among six candidates, 3-(3,7-dimethyloct-6-enylamino)propane-1,2-diol (Leadquest code name: 5755) was chosen for further development. Future work will involve synthesis of some derivatives of 5755 and biological experiments if any derivatives can control the biostimulation and improve reproductive efficiency in pigs.
제초성 Benzenesulfonyl urea 계 화합물의 형태와 반응성
성낙도(Nack Do Sung),유성재(Seong Jae Yu),이상호(Sang Ho Lee),고영관(Young Kwan Ko) 한국응용생명화학회 1996 Applied Biological Chemistry (Appl Biol Chem) Vol.39 No.3
The most stable stereo conformer in non substituted benzenesulfonyl urea, 1 was the II-keto form, which the molecule was intramolecular associated(H-bond) conformer between imide group and N atom on the pyrimidine ring. The hydrolytic degradation of 2 derivatives were proceeds by nucleophilic addition reaction(ρ$lt;0) with orbital controlled intermolecular interaction between LUMO with electron donating(σ$lt;0) groups of 2 and HOMO of water molecule. N-(4,6-disub. pyrimidine-2-yl)aminocarbonyl-2-(1,1-dimethoxy-2-fluoro)ethylbenzenesulfonamides, 3 and N-(4,6- disub. triazine-2-yl)aminocarbonyl-2-(1,1-dimethoxy-2-fluoro)ethylbenzenesulfonamides, 4 were synthesized and their herbicidal activities in vivo against bulrush (Scirpus juncoides.) were measured by the pot test under the paddy conditions. And the structure activity relationships(SAR) were analyzed by the multiple regression technique. The results of the SAR suggested that the 3 and 4 derivatives indicated dependent on the hydrophobicity of the 4,6-disubstituents and the heterocyclo group, where the optimal value ((log P)_(opt)) of hydrophobicity was 0.89. The pyrimidine substituents, 3 showed higher herbicidal activity than the triazine substituents, 4. Among them, 4,6-dimethoxypyrimidine substituent, 3a showed the best herbicidal activity.
제초성 Flazasulfuron 의 Smile 자리옮김 반응
성낙도(Nack Do Sung),이광재(Gwang Jae Lee),김용집(Yong Jip Kim),김대황(Dae Whang Kim) 한국응용생명화학회 1996 Applied Biological Chemistry (Appl Biol Chem) Vol.39 No.1
A series of the herbicidal pyridylsulfonyl areas, none substitutent. 1-(4,6-dimethoxypyrimidine-2-yl)-3-(2-pyridylsulfonyl) urea, 3 and 3-trifluoromethyl substitutent, 1-(4,6-ctimethoxypyrimidine-2-yl)-3-(3-trifluoromethyl-2-pyridylsulfonyl) urea, 5(Flazasulfuron) were syntbesizied and the rate of hydrolysis of their has been studied in 25%(v/v) aqueous dioxane at 45℃. From the results of solvent effect(m≪, n≪3 & |m|≪|ℓ|), thermodynamic parameter (△S=0.54∼-2.19e.u. & △H=0.025 Kcal.mol.^(-1)), hydrolysis product analysis, pK_a constant(3: 4.9 & 5: lit.4.6) and the rate equation, a marked difference in the kinetics of the reaction of 3 and 5(Flazasulfuron) was observed. It may be concluded that the hydrolysis of 5 proceeds through the A-S_N2Ar reaction via conjugate acid(5H^+) below pH 7.0, whereas, above pH 9.0, the hydrolysis proceeds through irreversibly (E₁)_(anion) and reversibly (E₁CB)_R mechanism via conjugate base(CB), respectively. But in case of 5, A-S_N2Ar, (E₁)anion and (E₁CB)_R mechanism involved Smile rearrangement. The mate of rearrangement of 5 to a 3-trifluoromethyl-2-pyridylpyrimidinyl urea(PPU) in acid and 3-trifluoromethyl-2-pyridyl-4.6-dimethoxypyridinyl amine (PPA) in base was increased about 3.5 times by the introduction of trifluoromethyl group in the 3-position on the 2-pyridyl ring. From the basis of these findings, a possible mechanism for the hydrolysis of 5 was proposed and discussed.
새로운 Ortho 이치환 Benzenesulfonyl Urea 유도체의 제초활성과 수용액중의 잔류성
성낙도(Nack Do Sung),김용집(Yong Jip Kim),장해성(Hae Sung Chang),김대황(Dae Whang Kim) 한국응용생명화학회 1995 Applied Biological Chemistry (Appl Biol Chem) Vol.38 No.6
The new sixteen herbicidal N-2-(1-hydroxy-2-fluoroethyl)-6-substituted(X)-benzenesulfonyl-N`-4,6-dimethoxypyrimidinyl-2-yl urea derivatives(S) were synthesized and thier herbicidal activities(pI_(50)) in vivo against rice(Orysa Sativa L.), Barnyard grass(Echninochloa orizicola) and Bulrush(Scirpus juncoides) were measured by the pot test under paddy conditions. The structure activity relationship(SAR) were studied using the physicochemical parameters of ortho-substituents(X) and hydrolysis rate constant(logk) and herbicidal activities by the multiple regression technique. The SAR suggested that the herbicidal activities were more dependant on the hydrolysis rate constant(logk$gt;0) than the steric constants (Es$lt;L1(or B₄)$lt;0), small width(B₄) and length(L₁). Among them, halogens(2 & 5), methyl(15) and non(H) substituent(1) showed higher herbicidal activity for weeds which was not tolerent to rise and weeds. The herbicidal activity was increased and the persistency in aqueous solution was decreased by electron donating(σ0$lt;0) groups as ortho-substituent(X). From the relationship equation between herbicidal activity and hydrolysis rate constant, it was assumed that the both reactions would be proceeds with similar process. And the conditions on the ortho substituents to show higher herbicidal activity and the persistency in aqueous solution were also discussed.