• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.597-604
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• 2001

The reaction of [(2-N,N-dimethylaminomethyl) pheny] methylvinychlorosiane with t-BuLi in hexane solvent gave dimers, five isomeric 1,3-disilacyslobutanes which were weparated and charaterized. In trapping experiments with various trapping agents, no corresponding silene-trapping aduct was observed. We suggest that more important species for the formation of five isomeric dimers might be the zwitterionic species generated by virtue of intramolecular donor atom rather than the silene.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1706-1712
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• 2014

The OH($X^2{\Pi}$, ${\upsilon}^{\prime\prime}=0,1$) internal state distribution following the reaction of electronically excited oxygen atom ($O(^1D_2)$) with cyclo-$C_3H_6$ has been measured using laser-induced fluorescence, and compared with that following the reaction of $O(^1D_2)$ with $C_3H_8$. The overall characteristics of the OH internal energy distributions for both reactions were qualitatively similar. The population propensity of the ${\Pi}(A^{\prime})$ ${\Lambda}$-doublet sub-level suggested that both reactions proceeded via an insertion/elimination mechanism. Bimodal rotational population distributions supported the existence of two parallel mechanisms for OH production, i.e., statistical insertion and nonstatistical insertion. However, detailed analysis revealed that, despite the higher exoergicity of the reaction, the rotational distribution of the OH following the reaction of $O(^1D_2)$ with $C_3H_8$ was significantly cooler than that with cyclo-$C_3H_6$, especially in the vibrational ground state. This observation was interpreted as the effect of the flexibility of the insertion complex and faster intramolecular vibrational relaxation (IVR).

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2473-2479
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• 2013

The kinetics of the radical-polar molecule reaction $CH_3+HBr{\rightarrow}CH_4+Br$ has been studied at temperatures between 150 and 1000 K using classical dynamics procedures. Potential energy surfaces constructed using analytical forms of inter- and intramolecular interaction energies show a shallow well and barrier in the entrance channel, which affect the collision dynamics at low temperatures. Different collision models are used to distinguish the reaction occurring at low- and high-temperature regions. The reaction proceeds rapidly via a complex-mode mechanism below room temperature showing strong negative temperature dependence, where the effects of molecular attraction, H-atom tunneling and recrossing of collision complexes are found to be important. The temperature dependence of the rate constant between 400 and 1000 K is positive, the values increasing in accordance with the increase of the mean speed of collision. The rate constant varies from $7.6{\times}10^{-12}$ at 150 K to $3.7{\times}10^{-12}$ at 1000 K via a minimum value of $2.5{\times}10^{-12}\;cm^3\;molecule^{-1}\;s^{-1}$ at 400 K.

• YAKHAK HOEJI
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• v.50 no.6
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• pp.403-408
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• 2006

1-Amino-5,6-dimethoxyindan hydrochloride was synthesized from 3- (3,4-dirnethoxyphenyl)propionic acid by intramolecular Friedel-Crafts acylation, oximation with hydroxylamine, and reduction with an overall yield of 74%. 2-Amino-5,6-dimethoxyindan hydrochloride was synthesized from 3-(3,4-dirnethoxyphenyl)propionic acid by intramolecular Friedel-Crafts acylation, oximation with isoamylnitrite, reduction in NaOH and reaction with HCI to form 5,6-dimethoxy-2-indanone, which was reacted with hydroxylamine and reduced with an overall yield of 42%. 5,6-Dimethoxyindan-1,2-dione-2-oxime, which was catalytically hydrogenated to afford cis-, and trans-1-amino-5,6-dimethoxyindan-1-ol as 3 : 1 ratio. This mixture was treated with Li and reacted with chloroacetyl chloride. Cis isomer was acylated and cyclized to synthesize rir -( ${\pm}$ )-7,8-dimethoxy-4,4a,5,9b-tetrahydroindeno[1,2-b][1,4]oxazin-3(2H)-one, but trans isomer was just acylated to form amide.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2673-2678
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• 2014

The detailed mechanisms of the efficient $\small{L}$-proline and pyrrolidine catalyzed transamidation of acetamide with benzylamine have been investigated using density functional theory (DFT) calculations. Our calculated results show: (1) the mechanisms of two catalytic cycle reactions are similar. However, the rate-determining steps of their reactions are different for the whole catalytic process. One is the intramolecular nucleophilic addition reaction of 1-COM, the other is hydrolysis reaction of 2-C. (2) COOH group of $\small{L}$-proline is essential for efficient transamidation. The computational results are in good agreement with the experiment finding and mechanism resported by Rao et al. for $\small{L}$-proline-catalyzed synthesis of amidesin good to excellent yields.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2700-2704
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• 2011

The 1:1 imine intermediate generated by the addition of primary amine to chloroacetone is trapped by N-isocyaniminotriphenylphosphorane in the presence of (E)-cinnamic acids and the corresponding iminophosphorane intermediate was formed. Disubstituted 1,3,4-oxadiazole derivatives are formed via intramolecular aza-Wittig reaction of the iminophosphorane intermediate. The reactions were completed in neutral conditions at room temperature. The disubstituted 1,3,4-oxadiazole derivatives were produced in excellent yields.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.229-236
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• 2000

The reaction of 6-chloro-2-hydrazinoquinoxaline 4.oxide(10) with acetylacetone or dibenzoylmethane gave 6-chloro-2-(3,5-disubstituted pyrazol-1-yl)quinoxaline 4-oxides (11) through the intramolecular·cyclization.The chlorination of compound 11 with phosphoryl chloride afforded 3,6-dichloro-2-(3,5-disubstituted pyrazol-1-yl)quinoxalines (12), whose reaction with hydrazine hydrate provided 6-chloro-3-hydrazinodehydes, benzenesulfonyl chloride, substituted benzoyl chlohdes or acyl chlorides gave novel pyrazolylquinoxalines (14-17).

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.305-312
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• 1998

Normal tensile strength in collagen fibrils is due to intermolecular and intramolecular crosslinks which are known to be altered in aging. Pyridinoline, a mature crosslink which is stable and nonreducible, is derived from two hydroxyallysine and one hydroxylysine residues of collagen fibrils. The excess formation of pyridinoline in collagen is associated with making the tissue stiffer, less soluble and less digestible by enzymes. Lysyl oxidase is the enzyme that initiates the biosynthesis or crosslinks in collagen by catalyzing the oxidative deamination of the lysyl and hydroxylysyl residues in these molecules, and its activity is inhibited by $\beta$-aminopropionitrile(BAPN). Our previous work demonstrated that the pyridinoline content of bone collagen significantly was increased during incubation for 5 weeks at 37$^{\circ}C$ invitro, but it was diecrased by the addition of ascorbic acdi(AsA). In this study, we clarified the specific action of AsA in aging process in vitro enzymatic reaction.

• Bulletin of the Korean Chemical Society
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• v.16 no.11
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• pp.1037-1042
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• 1995

The reaction of acetophenone 1-ureidoethylidenehydrazones 6 with a mixture of triphenylphosphine, carbon tetrachloride, and triethylamine in dichloromethane provides a general route to 1-(1-phenylethenyl)-5-(N-substituted amino)-1,2,4-triazoles 11 via the electrocyclization of the expected azino carbodiimide intermediates 9 to give the resonance stabilized azomethine imine 10a followed by a proton abstraction from the methyl group by amide anion. However, the same reaction of benzaldehyde 1-ureidoethylidenehydrazones 5 was unsuccessful. Under the same conditions, the reactions of benzaldehyde 1-N-acylureidoethylidenehydrazones 7 or acetophenone 1-N-acylureidoethylidenehydrazones 8 afforded 4H-1,2,4-triazolo[1,5-c][1,3,5]oxadiazines 16 or 17 via the zwitterionic species 15, or a [4+2] intramolecular cycloaddition from the carbodiimide intermediates 14, respectively.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1089-1093
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• 1994

Polyesters containing enaryloxynitriles moiety have been newly prepared from p-bis[1-[4-(3-hydroxypropyl)phenoxy]-2,2-dicyano vinyl]benzene (3) and common diols with terephthaloyl chloride. The copolyesters have a good solubility in common organic solvents as well as polar aprotic solvents. They undergo a curing reaction at around 350 $^{circ}C$ and show a 50-60${\%}$ of residual weight at 500 $^{circ}C$. The enhanced thermal stabilities were due to the intramolecular cyclization or intermolecular cross-linking reaction of the dicyanovinyl group incorporated into polyester by copolymerization.