• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1080-1084
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• 1994

Asymmetric inducing effects of substituents attached at nitrogen, the 5-position and boron in oxazaborolidine rings on asymmetric borane reduction of ketones were investigated. Thus, the effect of N-substituents examined with the oxazaborolidines prepared from (lR,2S)-N-alkyl norephedrine derivatives showed the remarkable decrease of enantioselectivities of the product alcohols by the variation of the steric size of alkyl groups on nitrogen from Me${\leftrightarro}$n-Bu(${\simeq}$Bn)${\leftrightarro}$ neopentyl${\leftrightarro}$i-Pr, such as 83${\%}$ ee with 5b, 22${\%}$ ee with 5c, 23${\%}$ ee with 5f, 16${\%}$ ee with 5e, and 3${\%}$ ee with 5d for the reduction of acetophenone. The presence of diphenyl groups at the 5-position enhanced the enantioselectivities dramatically. The effect of B-alkyl substituents in the oxazaborolidines derived from (lR,2S)-ephedrine showed that the enantioselectivities of product alcohols decreased gradually when the substituents were changed from hydrogen to steric bulky groups such as methyl, n-butyl, thexyl and phenyl.

• Journal of the Korean Chemical Society
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• v.17 no.3
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• pp.193-197
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• 1973

The correlation of the infrared carbonyl stretching frequency with substituents in benzanilides has been studied. The Hammett-type equation(1) was adopted for this correlation. Substituents in a C-phenyl-ring gave a better correlation with ${\sigma}^{+}$rather than ${\sigma}$, meanwhile, substituents in a N-phenyl-ring gave a better correlation with ${\sigma}$. When substituents are placed on both C-phenyl and N-phenyl ring, they influenced the carbonyl stretching frequency reasonably independently of each other. A conformation of benzanilide which accounts for the above observation has also been discussed.

• Textile Coloration and Finishing
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• v.25 no.2
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• pp.102-109
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• 2013

A new series of anthraquinoid magenta dyes having alkylphenyl substituents was synthesized and applied toward pure polypropylene fibers. The affinity of the dyes toward polypropylene fibers was increased gradually with the increase of the length of alkyl substituents. The optimum length of alkyl group was determined as heptyl substituents from the practical point of view. The color values of the dyes on polypropylene fabrics displayed slight bluish red, namely magenta which is more practical than primary red in color matching. The good fastness ratings to washing, rubbing and light were obtained for the dyes having longer alkyl groups than hexyl substituents. Expecially they exhibited ratings 4 of light fastness, which is higher than primary red dyes previously reported.

• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.32-36
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• 2000

A series of synthesized N-(2-fluoro-4-chloro-5-alkyloxyphenyl)-3,4-dimethyl-2-arylthio-5-oxo-2,5-dihydropyrrole derivatives as substrates were found to selectivity significantly with both rice plant (Oryza sativa L.) and weeds, barnyard grass (Echinochloa crus-galli) and bulrush (Scriptus juncoides) for those herbicidal activities at a rate of 0.1 kg/ha with post emergence under submerged conditions. The structure activity relationships (SARs) on herbicidal activity of $SR_{2}$=2-arylthio substituents on the pyrrole ring were analysized. From the results, the relative contribute orders of the $SR_{2}$ with phenyl group on the activity are meta > para > ortho-substituents. Among these compounds, the $R_{1}=propargyl$ (IA) subsrituents, $1{\sim}12$ showed higher activity than the $R_{1}$=2-chloro-2-propenyl (IB) substituents, $13{\sim}16$. The $SR_{2}$ groups of IA substituents shown that the optimal steric constant, $(Es)_{opt.}=3.25$ and m-phenylthio substituents were found to be -contribute the activity against barnyard grass. But the herbicidal activity of IB substituents against bulrush would depend upon the molar refractivity, $M_{R}$ constant of $SR_{2}$ group.

• Macromolecular Research
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• v.16 no.6
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• pp.532-538
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• 2008

Epoxy-based azopolymers were synthesized by the reaction of the diglycidyl ether of bisphenol A (DGEBA) or N,N-diglycidyl aniline (DGA) with disperse orange 3 (DO3) to give poly(DGEBA-co-DO3) or poly(DGA-co-DO3), respectively. Aniline-based azopolymers prepared from poly(DGA-co-An) precursors, synthesized by the reaction of DGA with aniline, were produced by the post-azo coupling reaction with diazonium salts containing various substituents. Holographic gratings were carried out to measure the diffractive efficiencies (DE) for the interference patterns of the $Ar^+$ laser from 50 to $300\;mW/cm^2$ intensity. The shorter repeating unit with higher chromophore density induced deeper surface relief gratings (SRG). Large surface gratings were observed for the aniline-based azopolymers with -COOH substituents, as compared with those for epoxy-based azopolymers. The aniline-based azopolymers with dimerized chromophores and various substituents were also synthesized to observe the effect of chromophore substituents and dimerization on the holography. The dimerized chromophores were more sensitively photoisomerized by the $Ar^+$ laser beam, and demonstrated a larger grating than that with one azo bond.

• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.56-62
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• 2011

Molecular docking of polyhydroxy substituted flavone analogues (1-25) as substrate molecules to the active site of tyrosinase (PDB ID: Deoxy-form (2ZMX) & Oxy-form (1WX2)) and Free-Wilson analysis were studied to understand the roles of hydroxyl substituents ($R_1-R_9$) in substrate molecules for the tyrosinase inhibitory activation. It is founded from Free-Wilson analysis that the $R_1$=hydroxyl among $R_1-R_9$ substituents had the strongest influence on the tyrosinase inhibitory activity. H-bonds between the hydroxyl substituents of substrate molecules and amino acid residues in the active site of tyrosinase were contributed to make a stable substrate-receptor complex compound. Particularly, it is proposed from the findings that the noncompetitive inhibitory activation would take place via H-bonding between peroxide oxygen (Per404) atom in the active site of tyrosinase and the hydroxyl substituents in substrate molecule.

• Journal of Ginseng Research
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• v.14 no.3
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• pp.427-431
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• 1990

To search for substituents of greens, several organic materials such as rice straw, barley straw, corn stem and manufactured compost were applied in a ginseng cultivating field. The yields of six year old ginseng harvested in the rice straw, barley strait and corn stem treated field were similar to or higher than that of the greens treated one. The varied amount of applied substituents resulted in a yield change, but statistical linearity was not found. The growth of ginseng aerial part and soil physicochemical property in the field fortified with these substituents showed similar results to those of the greens treated one. So, it is though that these organic materials can substitute for greens.

• The Journal of Natural Sciences
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• v.15 no.1
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• pp.47-56
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• 2005

The substituent dependence of geometric distortion through the two independent electronic substituent effects is analyzed for mono-substituted benzene derivatives of $C_{2v}$. Based on resonance structures, quantitative relationships expressing the resonance and field/inductive contribution terms in bond distortions are derived. The calculated field-effect parts of $C_{ipso}$_$C_{ortho}$ ring bonds increase and decrease compared to benzene for electropositive and electronegative substituents respectively. The nonbonded axial distance, $C_{ipso}$....$C_{para'}$ decreases for electronegative substituents and increases for electropositive substituents. As the electronegativity increases, the distance $C_{ortho}$....$C_{ortho'}$ increases. With the $\pi$-donors, $C_{meta}$....$C_{meta'}$ nonbonded distances are shorter compared to the ones of benzene, and for $\pi$-acceptors, the are longer. Our model based on valence bond approach predicts that the average bond length determined the area of ring, and the sum of the angles <$C_{ortho}$_$C_{ispo}$_$C_{ortho}$ and <$C_{meta}$_$C_{para}$_$C_{meta}$ determines the axial distance.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2217-2222
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• 2009

The transition structures for the epoxidations of ethylene and the disproportionations by the dioxiranes of phosphines, phosphites and sulfides were studied with density function theory methods using the Becke3LYP functional and 6-311+G(2d,p) basis set. When the dioxiranes have methyl substituents rather than hydrogen substituents, the reaction barriers ($E_{TS}$) become higher in their epoxidations of ethylene by the steric hindrance, but become lower in their disproportionations of phosphines, phosphites and sulfides, which indicates that the nature of the dioxiranes seems to be electrophilic and in their disproportionations the reaction barriers are effected both by the electrophilicity and the steric hindrance. The steric factors in the disproportionations were calculated and more bulky substituents at dioxiranes may be necessary to retard the disproportionation and to enhance the epoxidation.

• Journal of the Korean Chemical Society
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• v.11 no.4
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• pp.170-172
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• 1967

2-Phenyl-5-substituted phenyltetrazole and 2-substituted phenyl-5-phenyltetrazole were prepared from the corresponding hydrazone and phenyl azide with 2-methoxyethanol and metallic sodium as reaction medium at 110~115 $^{\circ}C$. At this reaction condition, however, the preparation of 2-substituted phenyl-5-phenyltetrazoles with substituents of relatively high Hammett substituent constant was unsuccessful. Surprisingly it was found that the solvent molecule was exchanged with substituent during the reaction when tried to obtain 2-m-fluorophenyl-5-phenyltetrazole using benzaldehyde m-fluorophenylhydrazone as starting material. Also disscussed the effect of electronic nature of substituents on the formation of 2,5-diphenyltetrazole derivatives.