• Journal of the Korean Chemical Society
• /
• v.19 no.2
• /
• pp.116-122
• /
• 1975

Determination has been made of the kinetics of the reaction of benzyl arenesulfonates with pyridine in acetone. The substituent effects of the leaving groups in benzyl arenesulfonates are correlated by Hammett equations, with the exception of p-MeO and $p-NO_2$ groups, where the electron attracting substituents in the benzyl arenesulfonate increase the rate. The substituent effects of the leaving groups are as expected due to the nucleophilic attack of amine on the benzyl carbon atom. This can be understood in terms of changes in bond formation (C-N) and bond breaking (C-O) in the transition state with charges in electron-attracting ability of the substituents. The predicted substituent effects may indicate a small increase in bond formation and thus a tighter transition state, in benzyl p-bromobenzene sulfonate than in benzyl p-nitrobenzenesulfonate. Predicting made by Thornton concerning the substituent effects on $S_N2$ transition state structures agrees with the changes in bond formation and bond breaking.

• Journal of the Korean Chemical Society
• /
• v.40 no.4
• /
• pp.249-253
• /
• 1996

The synthesis of new 5-benzyl-4-cyanomethyl-2-methylpyrimidine derivatives (5) containing chloro, methoxy, ethoxy, phenoxy and anilino groups at 6-position on the pyrimidine ring were prepared from 5-benzyl-4-chloro-2-methylpyrimidine derivatives (3) and tert-butylcyanoacetate. The derivatives of 5-benzyl-4-chloro-2-methylpyrimidine (3) containing chloro, methoxy, ethoxy, isopropoxy, phenoxy and anilino groups at 6-position on the pyrimidine ring were prepared from 5-benzyl-4,6-dichloro-2-methylpyrimidine (2).

• Macromolecular Research
• /
• v.16 no.3
• /
• pp.238-246
• /
• 2008

A new strategy using protection-deprotection chemistry was used to prepare branched polymers using the ATRP method only. Among the several monomers with different protecting groups, vinyl benzyl t-butyloxy carbonate (VBt-BOC) and 4-methyl styrene (4-MeSt) could be polymerized successfully to form backbones using the ATRP method in a controlled fashion. The protected groups in the backbones were converted to alkyl bromides and used as initiating sites for branch formation. The benzyl t-butyloxy carbonate groups in the backbones containing VBt-BOC units were first deprotected to benzyl alcohol by trifluoroacetic acid, then converted to benzyl bromide by reacting them with triphenylphosphine/carbon tetrabromide. The benzyl bromide groups in the backbones containing 4-MeSt units could be generated by bromination of the methyl groups using N-bromosuccinimide/benzoyl peroxide. The structures of the prepared polymers were well-controlled, as evidenced by the controlled molecular weight as well as the narrow and unimodal molecular weight distribution.

• Journal of the Korean Chemical Society
• /
• v.19 no.6
• /
• pp.449-453
• /
• 1975

Substituent effect of the leaving groups of the reaction of benzyl arenesulfonate with dimethylanilines in acetone at $35^{\circ}C$ was obtained with the following results. 1. Substituent effect of the leaving groups was not variable when changed from pyridine to N,N-dimethylaniline in nucleophile 2.In acetone, the Hammett ${\sigma}$ constant of p-MeO of the leaving group was -0.35. 3. The weaker the nucleophilicity in dimethylaniline, the stronger the movement of electron from N to C, and the cleavage of the C${\ldots}$0 bond in transition state proceeds.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.9
• /
• pp.805-808
• /
• 1995

Diacetone-D-glucose was converted into 5-azido-6-O-benzoyl-3-O-benzyl-5-deoxy-1,2-O-isopropylidene-α-D-glucofuranose. After removal of isopropylidene and benzoyl protecting groups, hydrogenation performed reduction of azide and subsequent cyclization by reductive amination to give 3-O-benzyl-1-deoxy nojirimycin in high yield. The second azide group was introduced on 2-carbon by selective substitution reaction, and reduction of azide to amino group gave titled compound.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.7
• /
• pp.1353-1358
• /
• 2008

Benzyl arylether dendrimers with zinc porphyrin core and terminal vinyl groups have been synthesized and their photophysical properties and the influence of dendritic environments were investigated. Free base porphyrin-cored benzyl arylether dendrimers 1a-1c and 3a-3c, and their zinc derivatives 2a-2c and 4a-4c have been prepared. Absorption spectra are similar for all porphyrin-cored benzyl arylether dendrimers, except that absorption intensity at 280 nm increases in the higher generation of dendrimer. Fluorescence spectra are similar with two bands for all free base porphyrin dendrimers 1a-1c and 3a-3c, although fluorescence intensity ratio of shorter wavelength emission band to longer wavelength band varies with the generation of dendrimer. Emission efficiencies of 1a-1c and 3a-3c are lower than that of TTP. Emission efficiencies of 2a-2c and 4a-4c are higher than that of ZnTTP. Absorption and emission properties of 1a-1c, 2a-2c, 3a-3c, and 4a-4c were affected negligibly with dendritic environments.

• Polymer(Korea)
• /
• v.26 no.3
• /
• pp.344-352
• /
• 2002

In this work, two thermal cationic latent catalysts, i.e., triphenyl benzyl phosphonium hexafluoroantimonate (TBPH) and benzyl 2-methylpyrazinium hexafluoroantimonate (BMPH) were newly synthesized. And the thermal and mechanical properties of difunctional epoxy (diglycidylether of bisphenol h, DGEBA) resins initiated by 1 phr of either TBPH or BMPH catalyst were investigated. As experimental results, the epoxy/TBPH system showed higher curing temperature and critical stress intensity factor ($K_{IC}$) than those of epoxy/BMPH. This could be interpreted in terms of slow thermal diffusion rate and bulk structure of four phenyl groups in TBPH. However, the decomposed activation energy determined from Coats-Redfern method was lower in the case of epoxy/TBPH. This result was probably due to the fact that broken short chain structure was developed by steric hindrance of TBPH.

• Archives of Pharmacal Research
• /
• v.20 no.1
• /
• pp.53-57
• /
• 1997

For the purpose of defining the effects of the N-substituted alkyl groups on the anticonvulsant activities of N-Cbz-.alpha.-aminosuccinimides, various (R)- and (S)-N-alkyl substituted N-Cbz-.alpha.-aminosuccinimides (1 and 2) were prepared from the corresponding (R)- and (S)-N-Cbz-aspartic acid by using known reaction and were evaluated the anticonvulsant activies in the MES and PTZ tests, including their neurotoxicities. The most active compound in the MES test was (R)N-Cbz-.alpha.-amino-N-methylsuccinimide (1b) $(ED_{50}=52.5 mg/kg, Pl=3.2)$. And in case of the PTZ test, (R)-N-Cbz-.alpha.-amino-N-ethylsuccinimide (1c) was the most active compound $(ED_{50}/=32.5mg/kg, Pl=3.1)$. The order of anticonvulsant activities of these compounds against the MES test, as judged from the ED_50values for the R series (1), was N-methyl > N-isobutyl > non-substituted > N-ethyl, N-allyl > N-benzyl compound; for the S series (2) N-methyl > N-altyl > non-substituted > N-isobutyl > N-ethyl > N-benzyl compound. The anticonvulsant activities in the PTZ tests of these compounds exhibited somewhat different pattern ; for the R series (1) Nethyl > N-methyl > N-isobutyl> non-substituted > N-allyl > N-benzyl compound in order of decreasing activity; for S series (2) N-ethyl > N-allyl, non-substituted > N-isobutyl > N-methyl > N-benzyl compound in order of decreasing activity.

• Journal of Environmental Health Sciences
• /
• v.29 no.2
• /
• pp.16-22
• /
• 2003

BBP (Butyl benzyl phthalate), a widely used plasticizer. can enter the food and environment as consequence of its manufacture, use, and disposal. BBP was found to be developmental and teratogenic or endocrine disrupting chemical in rats. The effects of BBP were investigated in female rats (P) and second generation (F1) via lactations. Sprague-Dawley were given BBP by oral administration at 0, 5, 10, 100, 1000 mg/kg on day 0 to 21 of lactation period. The results were as follows : At maternal findings, there were some significant changes (p<0.05) in relative organ weight, especially liver and uterus weight by BBP administration. In estrous cycle, high treated group was inclined to be proestrus or estrus compared to control group. BBP indues estrous cycle earlier than the control group. At fetal findings, there were some significant changes in relative liver and spleen weight, especially 100, 1000 mg/kg administered groups. The relative weight of ventral prostate was decreased, so it was represent to dose-response tendency. Parent rats (P) were detected monobenzyl phthalate (MBeP) 3.21~5.81 $\mu\textrm{g}$/ml in 100, 1000 mg/kg dose groups. MBeP of male and female fetuses (F1) were detected at the level of 1.21~2.63 $\mu\textrm{g}$/ml of serum. Male serum concentration oi MBeP was higher than the females'. Estrogen receptor $\alpha$ expression by BBP and bisphenol A in uterus and testis of F1 were studied. The ER$\alpha$ expression were increased in F1 male testis and female uterus. F1 male showed distint ER$\alpha$ expression, especially in the combined exposrue. Synergistic ER$\alpha$ expression was found by combined treatment group of BBP and bisphenol A. From the above results, it could be concluded that the effects of dams and F1 by BBP administration during lactation period were estrogenic, and BBP can transfer to F1 via lactation, and make estrogenic at F1 reproductive organs.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.35 no.4
• /
• pp.271-276
• /
• 2009

The 3-dimensional quantitative structure-activity relationships (3D-QSARs) models between the substituents with changing groups ($R_1$ & $R_2$) of 4-($R_1$)-benzyl alcohol and 4-($R_2$)-phenol derivatives as substrate molecule and their inhibitory activities against tyrosinase were derived and discussed quantitatively. The optimized CoMSIA 2 model have best predictability and fitness ($r^2\;=\;0.858$ & $q^2\;=\;0.951$). The contour maps of optimized CoMSIA 2 model showed that, the inhibitory activities of the analogues against tyrosinase were expected to increase when hydrophobic favor, negative charge favor, steric disfavor and hydrogen bond donor disfavor groups were substituted at the $R^2$ position. When the positive charge and the hydrogen bond donor favor groups were substituted at the $R_1$ position, it is predicted that the substituents will be able to increase the inhibitory activity. However, hydrogen bond acceptor did not affect inhibitory activities of tyrosinase.