• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.233-242
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• 2012

A new synthetic method for dimethyl 2,3-dihydrobenzo[b]oxepine-2,4-dicarboxylates and methyl 2-(2-carbomethoxybenzo[b]furan-3-yl)propanoates by an intramolecular conjugate displacement reaction or an $S_N2$ reaction of acetates of Morita-Baylis-Hillman adducts of methyl (2-formylphenoxy)acetates has been described.

• Macromolecular Research
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• 제17권10호
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• pp.739-745
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• 2009

N,N'-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids 3a-g were synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride 1 with two equimolars of Lalanine 2a, L-valine 2b, L-leucine 2c, L-isoleucine 2d, L-phenyl alanine 2e, L-2-aminobutyric acid 2f and L-histidine 2g in an acetic acid solution. Seven new poly(amide-imide)s PAIs 5a-g were synthesized through the direct polycondensation reaction of seven chiral N,N'-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids 3a-g with bis(3-amino phenyl) phenyl phosphine oxide 4 by two different methods: direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride ($CaCl_2$/pyridine (py), and direct polycondensation in a tosyl chloride (TsCl)/pyridine (py)/N,N-dimethylformamide (DMF) system. The polymerization reaction produced a series of flame-retardant and thermally stable poly(amide-imide)s 5a-g with high yield. The resulted polymers were fully characterized by FTIR, $^1H$ NMR spectroscopy, elemental analyses, inherent viscosity, specific rotation and solubility tests. Data obtained by thermal analysis (TGA and DTG) revealed that the good thermal stability of these polymers. These polymers can be potentially utilized in flame retardant thermoplastic materials.

• 대한화학회지
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• 제27권2호
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• pp.157-164
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• 1983

N-Methylidene-2,6-diethylaniline (III)은 2,6-diethylaniline (II)과 과량의 paraformaldehyde와의 반응으로 만들었으며, 이 화합물 III에서 N=$CH_2$ 프로톤은 AB 스핀계를 나타냈다. 화합물 III과 chlorocarbonylsulfenyl chloride(IV)를 반응시켜서 N-(chloromethyl)-N-(2,6-diethylphenyl)-carbamoylsulfenyl chloride(V)를 합성하였다. 화합물 V와 여러 종류의 알콜을 반응시켜서 Alkyl N-(chloromethyl)-N-(2,6-diethylphenyl)-carbamoylsulfenate esters(VI ${\sim}$XVI)를 71{\sim}$95%의 수득률로 합성하였다. VI${\sim}$XVI은 서서히 분해되지만 S-O 결합이 S=O결합으로 변하지는 않았다. 과량의 알콜은 V의 2가 황과 N-chloromethyl기의 ${\alpha}$-탄소에 대해 친핵성 공격을 할 수 있었으며, 이렇게 하여 생긴 화합물 (XVII, XVIII)은 상당한 안정성을 가지고 있었다.

• Bulletin of the Korean Chemical Society
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• 제13권5호
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• pp.526-528
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• 1992

1-Aminothiohydantoin derivatives were prepared in good yields by the reaction of alkyl or arylisothiocyanates with ethyl hydrazinoacetate hydrochloride in presence of triethylamine. The intermediates, N-amino-N-ethoxycarbonylmethyl-N'-aralkylthioure as, which were formed during the reaction and could be transformed into the appropriate 1-aminothiohydantoins, were isolated and characterized.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4117-4121
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• 2012

The solvolysis rate constants of allyl chloroformate ($CH_2=CHCH_2OCOCl$, 3) in 30 different solvents are well correlated with the extended Grunwald-Winstein equation, using the $N_T$ solvent nucleophilicity scale and $Y_{Cl}$ solvent ionizing scale, with the sensitivity values of $0.93{\pm}0.05$ and $0.41{\pm}0.02$ for l and m, respectively. These l and m values can be considered to support a $S_N2$ reaction pathway. The activation enthalpies (${\Delta}H^{\neq}$) were 12.5 to 13.4 $kcal{\cdot}mol^{-1}$ and the activation entropies (${\Delta}S^{\neq}$) were -34.4 to -37.3 $cal{\cdot}mol^{-1}{\cdot}K^{-1}$, which is also consistent with the proposed bimolecular reaction mechanism. The solvent kinetic isotope effect (SKIE, $k_{MeOH}/k_{MeOD}$) of 2.16 was also in accord with the $S_N2$ mechanism. The values of product selectivity (S) for the solvolyses of 3 in alcohol/water mixtures was 1.3 to 3.9, which is also consistent with the proposed bimolecular reaction mechanism.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2143-2146
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• 2010

A selective synthetic method of the 2,5-biaryltriazolones has been developed via copper-catalyzed N-arylation reaction. Aryltriazolones, which were readily prepared from commercially available compounds, were N-arylated to 2,5-biaryltriazolones with high regioselectivity. This approach allows for access to a variety of 2,5-biaryl-1,2,4-trizol-3-ones in a simple and practical manner.

• 한국세라믹학회지
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• 제26권1호
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• pp.31-36
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• 1989

In order to synthesize AlN-polytypes from AlN-SiO2-Al2O3 system, composition A (AlN/SiO2/Al2O3=1/0.3/0.05, mole ratio) and composition B(AlN-SiO2-Al2O3=1/0.2/0.05, mole ratio) were used. AlN-polytypes were produced by nitriding the mixture at 175$0^{\circ}C$~190$0^{\circ}C$ under N2 atmosphere. For lower reaction temperature, 15R phase was produced and in the case of higher reaction temperature, AlN phase was only produced. As each composition was heated at 185$0^{\circ}C$ in N2 atmosphere, produced main phases were 15R phase for composition A and 21R phase for composition B respectively. The fracture surfaces of produced reactants showed porous skeleton structure.

• 대한화학회지
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• 제24권2호
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• pp.150-154
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• 1980

Benzyl benzenesulfonate와 피리딘의 반응속도를 아세톤 용매중에서 20∼$40^{\circ}C$ 및 1∼2000 bars에서 전기전도도법으로 측정하였다. 반응속도는 온도 및 압력이 증가함에 따라 증가하였다. 이 반응의 활성화엔탈피$({\Delta}H^{\neq})$, 엔트로피$({\Delta}S^{\neq})$ 그리고 활성화부피$({\Delta}V^{\neq})$를 구하였다. 이 반응에서 압력변화에 대한 $({\Delta}H^{\neq})$와 $({\Delta}S^{\neq})$사이에 등속관계가 성립하였으며 등속온도는 $342^{\circ}K$였다. 이상의 결과로 본 반응은 전이상태에서 $C{\cdots}N$ 결합형성이 주로 반응속도를 결정하는 $S_N2$ 반응 메카니즘으로 진행된다는 것을 알았다.

• 약학회지
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• 제28권2호
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• pp.97-100
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• 1984

We have investigated the feasibility of using cyclic ambident nucleophiles in s-triazine ring transformation reaction and found that they can replace the $N_{1}-C_{2-N_{3}$ fragment of s-triazine directly in basic conditions, yielding the corresponding bicyclic products. In this paper, we described the reaction and mechanistic aspects of s-triazine to pyrimidopyrimidine transformation by 6-aminouracil derivatives. This type of ring transformation is supposed to be first attempt that deals with the successful s-triazine to bicyclic heterocycle transformation.

• 대한화학회지
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• 제41권5호
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• pp.256-265
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• 1997

토양과 수질시료 중에서 nitrite, nitrate 그리고 ammonia성 질소를 빠르고 연속적으로 정량할 수 있는 방법에 관하여 연구하였다. 실제시료를 측정하기전에 각 성분의 표준시료를 사용하여 FIA의 구조적 인자(주입 양, 반응코일 길이 그리고 흐름속도)를 결정하였다. Nitrite는 Griess reaction에 의해 sulfanilamide와 반응 후 N-(1-naphthylenediamine dihydrochloride)과 결합하여 azo 색소를 형성시킨 후 540 nm에서 측정하였고, nitrate는 hydrazine을 사용하여 nitride로 환원시킨 후 측정하였다. Ammonia는 Nessler법을 사용하여 440 nm에서 측정하였다. 최적 조건에서 $N(NO_2^-),\;N(NO_3^-)와\;N(NH_4^+)$의 검출한계(S/N=3)는 0.1 ㎍/ML, 0.4 ㎍/mL 그리고 0.3 ㎍/ML이었다. 실제시료를 비색법, ion chromatography 및 FIA로 측정하여 비교한 결과 상호 일치성이 80~125%로 나타내어 만족스러웠다. 시료의 주입횟수는 30회/시간 이상으로 조절할 수 있었다.