• 한국응용과학기술학회지
• /
• 제33권3호
• /
• pp.492-497
• /
• 2016

The intermediate product resulting from the radical degradation experiment of PCE and the atomic charge gained through Gaussian03W were compared against each other. The result was that the ratio of PCE radical degradation was almost 98% or higher after the 9 hr point in reaction time. The reaction speed constant was $0.16hr^{-1}$ and it followed the first reaction. We could see that at each location of the PCE molecule, dechlorination happened at a point where the negative atomic charge was the greatest. Moreover, the intermediate product of PCE radical degradation that was confirmed in the experiment and literature coincided exactly with the intermediate product in the atomic charge calculation. Therefore, when the atomic charge is calculated, the radical degradation pathway of the organic chlorine compound could be forecast.

• Bulletin of the Korean Chemical Society
• /
• 제29권5호
• /
• pp.1018-1024
• /
• 2008

Photolysis of 2-(pentamethyldisilanyloxy)phenylpentamethyldisilane 1 in methanol provides five photoproducts 3, 4, 5, 6, and 7. Compounds 3 and 4 were probably formed from the methanol addition reactions of silene intermediate 2 and the formation of 5, 6, and 7 can best be explained by the nucleophilic attack of methanol to silicon atom in pentamethyldisilanyloxy or pentamethyldisilanyl group of the photoexcited state of 1. Irradiation of 1 in n-hexane gives a photoproduct 6 via silyl radical intermediate 8 and a novel intramolecular cyclization photoproduct 11 via silene 9 and silyl radical intermediate 10. Irradiation of 1 in deaerated methylene chloride in the presence of acetone affords a novel photoproduct 11 and phenol 7 but the expected photoproducts from the reaction of the silene intermediate with acetone were not obtained.

• Bulletin of the Korean Chemical Society
• /
• 제22권8호
• /
• pp.857-866
• /
• 2001

Efficient syntheses of PGI2 analogue 2a and its epimer 3 have been accomplished. Using aryl iodide 6 as the common intermediate, either radical or palladium-assisted tandem alkene insertion strategies have been employed for construction of the benzoprostacyclin framework.

• 대한화학회지
• /
• 제24권3호
• /
• pp.250-258
• /
• 1980

여러종류의 자유라디칼들이 이소니트릴에 첨가되어 중간체인 imidoyl 자유라디칼 RN=CR'을 형성한다. 이것은 또한 imine으로부터 imidoyl hydrogen 을 떼어 내는 다음과 같은 반응에 의해서도 생성될 수 있다. RN=C(H)R' ＋ R"${\cdot}{\rightarrow}$ RN=CR' ＋ R"-H 중간체인 imidoyl 자유라디칼은 ${\beta}$-cleavage 및 aton transfer 반응을 통해서 안정된 분자를 형성한다. ${\beta}$-cleavage는 imidoyl 자유라디칼의 구조에 따라서 두개의 다른 방향으로의 반응이 가능하다. Cyanide transfer와 소위 말하는 정상적인 ${\beta}$-cleavage가 그러한 반응들이다. t-Butoxy 자유라디칼이 t-butylisonitrile 7에 첨가되면 중간체인 t-Bu-N=C-O-Bu-t가 생성되는데, 이것은 ${\beta}$-cleavage반응을 통해서 t-butylisocyanate와 t-butyl 자유라디칼을 형성한다. Phenyl 자유라디칼은 7에 첨가되어 중간체인 t-Bu-N=$C-C_6H_5$를 형성하는데 이것은 cyanide transfer 반응을 통해서 benzonitrile과 t-butyl 자유라디칼로 분해된다. 여기서 생성되는 t-butyl 자유라디칼은 다시 7에 첨가하여 intermediate인 자유라디칼 t-Bu-N=C-Bu-t을 형성하고, 이것은 다시 pivalonlonitrile과 t-butyl 자유라디칼로 분해되는데 이러한 반응이 반복되므로 radical chain isomerization을 일으킨다. Silyl 자유라디칼은 7에 첨가되어 t-Bu-N=$C-Si(CH_3)_3$를 형성하고, 이것은 cyanide transfer 반응을 거쳐서 다시 $(CH_3)_3$SiCN과 t-butyl 자유라디칼로 분해된다.

• Bulletin of the Korean Chemical Society
• /
• 제10권4호
• /
• pp.374-377
• /
• 1989

Photolysis of dichlorodiphenylmethane in glassy 2-MeTHF at 77K results in the formation of diphenylcarbene and the diphenylchloromethyl radical, which were detected by their flourescence emission and excitation spectra. The relative yield of the carbene to radical is shown to vary dramatically as a function of irradiation time. The photolability of the radical is also demonstated. These results were interpreted in terms of a two step mechanism, where the diphenylchloromethyl radical is an intermediate in the formation of diphenylcarbene.

• Bulletin of the Korean Chemical Society
• /
• 제16권3호
• /
• pp.285-287
• /
• 1995

• 한국미생물·생명공학회지
• /
• 제44권3호
• /
• pp.278-284
• /
• 2016

기능성으로 각광 받는 블루베리, 아로니아, 귀리, 단호박, 생강의 국내외 중간소재를 구입하여 기능성 성분을 비교, 분석하였다. 시판 중간소재 80% 메탄올 추출물의 Total phenolics contents (TPC), total anthocyanins contents (TAC), total flavonoids contents (TFC)를 측정하였고, ABTS radical 소거능, DPPH radical 소거능을 통해 항산화능을 측정 후, 통계적 유의성을 분석하였다. TPC (mg gallic acid equivalent/100 g dried sample)와 TFC (mg catechin equivalent/ 100 g dried sample)의 경우, 모두 국내산 블루베리(TPC, 2,917 ± 200; TFC, 1,327 ± 31)와 단호박(TPC, 476 ± 20, TFC, 23 ± 2)이 국외산 보다 높았고, 국외산은 아로니아, 귀리, 생강의 중간소재가 더 높았다. TAC (mg cyaniding-3-glucoside/100 g dried sample)는 국내산 블루베리(949 ± 57), 국외산 아로니아(2,032 ± 153)가 각각 높았다. 항산화능(mg vitamin C equivalent/100 g dried sample)은 ABTS radical 소거능의 경우, 국내산 블루베리(7,050 ± 321), 단호박(311 ± 8), 생강(3,322 ± 109)이 국외산보다 높았고, DPPH radical 소거능의 경우, 국외산 아로니아(12,667 ± 437), 생강(2,067 ± 99) 중간소재가 국내산보다 높게 나왔다. 이와 같이 국외산 중간소재와의 비교를 통해 국내산 농산물을 이용한 중간소재의 기능성 성분에 관한 기초자료를 제공하고, 새로운 기능성 중간소재 개발에 활용할 수 있을 것이다.

• Macromolecular Research
• /
• 제15권1호
• /
• pp.31-38
• /
• 2007

Pentamethylcyclopentadienyltitanium trichloride, bis(cyclopentadienyl)titanium dichloride ($Cp_2TiCl_2$), and bis(pentamethylcyclopentadienyl)titanium dichloride were used in the polymerization of styrene without the aid of Group I-III cocatalysts. The properties of the resulting polymer indicated that polymerization was more controlled than in thermal polymerization. The kinetic studies indicated that a lower level of termination is present and that the polymer chain can be extended by adding an additional monomer. To elucidate the mechanism of polymerization, a series of experiments was performed. All results supported the involvement of a radical mechanism in the polymerization using $Cp_2TiCl_2$. The possibility of atom transfer radical polymerization (ATRP) mechanism was investigated by isolating the intermediate species. We could confirm the activation step from the reaction of 1-PEC1 with $Cp_2TiCl$ by detecting the coupling product of the generated active radicals. However, the reversible deactivation reaction competes with other side reactions, and it detection was difficult with our model system.

• Bulletin of the Korean Chemical Society
• /
• 제35권11호
• /
• pp.3373-3376
• /
• 2014

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권14호
• /
• pp.5951-5956
• /
• 2015

Background: To evaluate the rate of pathologic high-risk factors, intermediate-risk factors, and treatment outcomes in early-stage cervical cancer patients undergoing radical hysterectomy and pelvic lymphadenectomy (RHPL). Materials and Methods: Medical records of stage IA-IIA1 cervical cancer patients who underwent RHPL during the 2006 to 2012 time period and patient follow-up data until December 2013 were reviewed. Results: Of 331 patients, 52 women (15.7%) had pathologic high-risk factors and 59 women (17.8%) had intermediate-risk factors without high-risk factors. All studied patients had an initial complete response. At median follow-up time of 40.9 months (range 1-103.3 months) and mean follow-up time of$ 43.3{\pm}25.3$ months, 37 women had disease recurrence and 4 women had died of disease. The most common site of recurrence was the pelvis (64.8%). Five-year and 10-year disease free survival rates were 96.1% and 91.5%, respectively. Five-year and 10-year overall survival rates were 100% and 99.4%, respectively. Independent factors related to recurrence were pelvic node metastasis (odds ratio [OR], 2.670; 95%CI, 1.001-7.119), and >1/3 cervical stromal invasion (OR, 3.763; 95%CI, 1.483-9.549). Conclusions: The rates of pathologic high-risk and intermediate-risk factors should be considered and disclosed when counseling patients regarding primary treatment by RHPL. Oncologic outcomes of primary surgical treatment for early-stage cervical carcinoma were found to be excellent.