• Bulletin of the Korean Chemical Society
• /
• 제35권10호
• /
• pp.3001-3004
• /
• 2014

A series of hydroxyl-derivatized quaternized polymers were successfully synthesized by atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry), followed by quaternization reactions. ATRP was employed to synthesize poly(2-hydroxyethyl methacrylate) (PHEMA), followed by introduction of alkyne groups using pentynoic acid, leading to HEMA-Alkyne. 2-Azido-1-ethanol and 3-azido-1-propanol were combined with the HEMA-Alkyne backbone via click reaction, resulting in triazole-ring containing hydroxyl-derivatized polymers. Quaternization reactions with methyl iodide were conducted on the triazole ring of each polymer. Molecular weight, molecular weight distribution, and the degree of quaternization (DQ) were determined by gel permeation chromatography (GPC) and $^1H$ NMR spectroscopy. The average molecular weight ($M_n$) of the resulting polymers ranged from $5.9{\times}10^4$ to $1.05{\times}10^5g/mol$ depending on the molecular architecture. The molecular weight distribution was low ($M_w/M_n$ = 1.26-1.38). The transmission spectra of the 0.1 wt % aqueous solutions of the resulting quaternized polymers at 650 nm were measured as a function of temperature. Results showed that the upper critical solution temperature (UCST) could be finely controlled by the level of DQ.

• Bulletin of the Korean Chemical Society
• /
• 제8권2호
• /
• pp.96-101
• /
• 1987

2-Ethoxy-6-methoxy-5-cyano-3,4-dihydro-2H-pyran (1_a$), 2-n-butoxy-6-methoxy-5-cyano-3,4-dihydro-2H-pyr an (1b), 2-isobutoxy-6-methoxy-5-cyano-3,4-dihydro-2H-py ran ($1_c$), and 2-ethoxy-6-methoxy-3-methyl-5-cyano-3,4-dihydro -2H-pyran ($1_d$) were prepared by (4 + 2) cycloaddition reaction of methyl $\alpha$-cyanoacrylate with the corresponding alkyl vinyl ethers. Compounds $1_{a-d}$ were ring-open polymerized by cationic catalyst to obtain alternating head-to-head (H-H) copolymers. For comparison, head-to-tail (H-T) copolymer $3_a$ was also prepared by free radical copolymerization of the corresponding monomers. The H-H copolymer exhibited minor differences in its $1_H% NMR and IR spectra, but in the $^{13}C$ NMR spectra significant differences were observed between the H-H and H-T copolymers. Glass transition temperature ($T_g$) of H-H copolymer was higher than that of the H-T copolymer, but thermal decomposition temperature of the H-H copolymer was lower than that of the H-T copolymer. Compounds $1_a$, $a_b$, and $1_c$, copolymerized well with styrene by cationic catalyst, but compound 1d failed to copolymerize with styrene. All of the H-H and H-T copolymers were soluble in common solvents and the inherent viscosities were in the range 0.2-0.4 dl/g.

• Bulletin of the Korean Chemical Society
• /
• 제32권7호
• /
• pp.2260-2266
• /
• 2011

4-Chlorotetrazolo[1,5-a]quinoxaline (III) was synthesized by azide (2+3) cycloaddition of 2,3-dichloroquinoxaline (II). Compound (III) on further refluxing with hydrazine hydrate furnished 4-hydrazinotetrazolo[1,5-a]quinoxaline (IV). Further refluxing of (IV) with different aromatic aldehydes in methanol yielded corresponding Schiff's bases V(a-j). Various 4-aminotetrazolo[1,5-a]quinoxaline based azetidinones VII(a-j) were synthesized by stirring the compounds V(a-j), at low temperature, with equimolar mixture of chloroacetylchloride & triethylamine in dry benzene, while 4-aminotetrazolo[1,5-a]quinoxaline based thiazolidinones VIII(a-j) were synthesized by refluxing Schiff's bases V(a-j) with thioglycolic acid in oil-bath. The structures of all the compounds were confirmed on the basis of $^1H$-NMR & FT-IR spectral data. All the newly synthesized compounds were screened for in-vitro antimicrobial activity against E. coli, S. aureus, K. pneumoniae & P. aeruginosa & antifungal activity against C. albicans. Few of them have exhibited the promising activity.

• 대한화학회지
• /
• 제42권1호
• /
• pp.69-77
• /
• 1998

4-styryl-2-azetidinone 7b의 bromoacetate에 의한 N-알킬화, 가오존분해, 산화, 말론산 에틸 마그네슘과의 축합 및 디아조 전달반응의 일련의 과정을 거처서 (3S,4S)-1-(t-butoxycarbonylmethyl)-3-[(S)-1-(t-butyldimethylsilyloxy)ethyl]-4-(2-diazo-2-ethoxycarbonyl-1-oxoethyl)-2-azetidinone(14)을 합성하였다. 또한 4-formyl-2-azetidinone 5b 의 Wittig 반응, ethoxycarbonylformonitrile oxide와의 1,3 이중극성 고리화 첨가반응, 촉매 수소화 및 디아조화 반응의 일련의 과정을 거쳐서 (3S,4S)-3-[(S)-1-(t-butyldimethylsilyloxy)ethyl]-4-(3-diazo-3-ethoxycarbonyl-1-hydroxypropyl)-2-azetidinone(21)을 합성하였다. 그러나 화합물 14 또는 21을 $Rh_2(OAc)_4$ 로 처리하여 1-hydroxycarbapenem 또는 1-hydroxycarbapenam으로 고리화하는 것을 성공하지 못하였다.

• 대한화학회지
• /
• 제26권3호
• /
• pp.172-178
• /
• 1982

4',5'-디히드로소랄렌(DHP)을 합성하여 상온 및 77K에서 이 화합물의 형광 양자수율은 0.08, 인광양자수율은 0.013, 형광수명은 0.95ns, 인광수명은 0.039s 임을 알았다. 이 결과로부터 형광수명은 5,7-디메톡시쿠마린보다 작은반면 소랄렌보다 크고 반면 인광수명은 DMC 보다 크고 소랄렌보다 작음을 알았다. 소랄렌 유도체들의 광독성을 분자적 차원에서 규명하고 DNA에의 광부가 반응을 알아내기 위하여 DHP와 TME의 광부가 반응을 연구하였다. 주 생성물은 TLC로 분석하고 Preparative TLC와 용매추출로 분리해냈다. 분리된 생성물의 구조는 질량분석기, UV, IR, NMR 그리고 원소분석결과에 의해 DHP와 TME외 광고리화첨가반응에 의한 생성물 임을 알았다. DHP는 형광의 자체소광 효과를 볼 수 없으며 TME, 에틸푸마레이트, 푸마로니트릴에 의해 형광이 효과적으로 소광된다. 광부가 반응의 양자수율과 소광실험에서 DHP의 광첨가반응은 단일상태와 삼중상태에서 다 일어나는 것으로 추측된다.

• 대한방사성의약품학회지
• /
• 제6권1호
• /
• pp.53-58
• /
• 2020

Pretargeting is a two-component strategy often used for tumor targeting to enhance the tumor-to-background ratio in cancer diagnosis as well as therapy. In the multistep strategy, the highly specific unlabeled monoclonal antibodies (mAbs) with the reactive site is allowed to get localized at tumor site first, and then small and fastclearing radiolabeled chelator with counter reactive site is administered which covalently attaches to mAbs via inverse electron demand Diels-Alder reaction (IEDDA). The catalyst-free IEDDA cycloaddition reaction between 1,2,4,5-tetrazines and strained alkene dienophiles aid with properties like selective bioconjugation, swift and high yielding bioorthogonal reactions are emergent in the development of radiopharmaceutical. Due to its fast pharmacokinetics, the in vivo formed radioimmunoconjugates can be imaged at earlier time points by short-lived radionuclides like ¹⁸F and ⁶⁸Ga; it can also reduce radiation damage to the normal cells. Ultimately, this review elucidates the updated status of pretargeting based on antibodies and IEDDA for tumor diagnosis (PET and SPECT) and therapy.

• Bulletin of the Korean Chemical Society
• /
• 제33권12호
• /
• pp.4161-4164
• /
• 2012

Density functional MO calculations for the methylsilole anion of $[C_4H_4SiMe]^-$ and methylgermole anion of $[C_4H_4SiMe]^-$ at the B3LYP (full)/6-311+$G^*$ level (GAUSSIAN 94) were carried out and characterized by frequency analysis. The ground state structure for the methylsilole anion and methylgermole anion is that the methyl group is pyramidalized with highly localized structure. The difference between the calculated $C_{\alpha}-C_{\beta}$ and $C_{\beta}-C_{\beta}$ distances are 9.4 and 11.5 pm, respectively. The E-Me vector forms an angle of $67.9^{\circ}$ and $78.2^{\circ}$ with the $C_4E$ plane, respectively. The optimized structures of the saddle point state for the methylsilole anion and methylgermole anion have been also found as a planar with highly delocalized structure. The optimized $C_{\alpha}-C_{\beta}$ and $C_{\beta}-C_{\beta}$ distances are nearly equal for both cases. The methyl group is located in the plane of $C_4E$ ring and the angle between the E-Me vector and the $C_4E$ plane for the methylsilole anion and methylgermole anion is $2.0^{\circ}$ and $2.3^{\circ}$, respectively. The energy difference between the ground state structure and the transition state structure is only 5.1 kcal $mol^{-1}$ for the methylsilole anion. However, the energy difference of the methylgermole anion is 14.9 kcal $mol^{-1}$, which is much higher than that for the corresponding methylsilole monoanion by 9.8 kcal $mol^{-1}$. Based on MO calculations, we suggest that the head-to-tail dimer compound, 4, result from [2+2] cycloaddition of silicon-carbon double bond character in the highly delocalized transition state of 1. However, the inversion barrier for the methylgermole anion is too high to dimerize.

• Bulletin of the Korean Chemical Society
• /
• 제33권7호
• /
• pp.2193-2199
• /
• 2012

A series of novel polytriazoleimides were prepared from various aromatic dianhydrides and a new kind of 1,2,3-triazole-containing aromatic diamine synthesized by the Cu (I)-catalyzed 1,3-dipolar cycloaddition reaction in DMAc, and characterized by FT-IR, $^1H$-NMR, XRD, DSC and TGA techniques. The results show the polytriazoleimides are soluble in most of strong polar solvents and have inherent viscosity values of 0.51-0.62 dL/g(DMAc). The polytriazoleimide films exhibit a tensile strength of 62.3-104.5 MPa and an elongation at breakage of 4.0-8.1%, a glass transition temperature ($T_g$) of $257-275^{\circ}C$, a decomposition temperature (at 5% weight loss) of $350-401^{\circ}C$ in $N_2$ atmosphere, and a dielectric constant of 2.47-3.01 at 10 MHz, which depend on the structure of the polymers. The polytriazoleimides perform good resistance to acid and alkali solution.

• 대한화학회지
• /
• 제28권5호
• /
• pp.284-292
• /
• 1984

치환체-E-arene-diazocyanides와 nitrosobenzenes의 (4+2) 고리첨가 반응의 배향성에 대한 치환기 및 산 촉매효과와 반응성을 예측하기 위하여 Diels-Alder 반응의 열 또는 촉매반응에 대하여 Frontier orbital theory (FMO)이론을 적용해서 CNDO/2 방법과 EHT-SPD 방법으로 고찰하였다. (1) 위 반응은 Hammett 식의 rho(${\rho}$)값이 양이므로 normal electron demand 반응형태를 가지며 4-FMO 및 Anh 방법이 실험적인 주 배향체와 일치함을 알았다. (2)전자끄는 기로 치환되면 dienophile의 HOMO, LUMO 궤도함수에너지가 낮아지고 반응성이 커지는 것을 알았다. (3)Lewis 산은 dienophile과 착물을 형성하고 dienophile의 LUMO계수를 정 반대로 분극시켜 주므로 주 배향제는 B형으로 예측된다. (4) diene HOMO-dienophile LUMO 상호작용의 안정화 에너지 (${\Delta}$E)와 Hammett식의 시그마 (${\sigma}$)값과의 그라프에서는 좋은 직선성을 보여 주었다.

• 폴리머
• /
• 제34권6호
• /
• pp.565-573
• /
• 2010

IPN 구조를 가지는 감습성 고분자 전해질로 사용하기 위하여 디브로모알칸과 가교가 가능한 copoly(2-(dimethylamino) ethyl methacrylate)(DAEMA)/butyl acrylate(BA)와 광가교가 가능한 copoly(methyl methacrylate) (MMA)/BA/2-(cinnamoyloxy)ethyl methacryate(CEMA)를 제조하였다. 전극의 기재 표면에 광조사에 의한 IPN-감습성 전해질의 부착을 위하여 3-(triethoxysilyl)propyl cinnamate(TESPC)을 전극표면에 처리하였다. IPN 구조의 감습성 고분자 필름은 copoly(DAEMA/BA), copoly(MMA/BA/CEMA) 및 1,4-dibromobutane(DBB) 가교제의 혼합 용액에 침적한 후에 UV 조사와 동시에 가열하여 제조하였다. IPN-전해질 고분자의 전극 기재와의 부착은 광화학적 $[2{\pi}+2{\pi}]$ 환화반응에 의하여 진행하였다. 얻어진 습도센서는 20~95%RH의 영역에서 매우 높은 감도와 1.5%RH 이하의 작은 히스테리시스를 보여주었다. 또한, 33~94%RH 사이에서 가습과 제습과정의 응답 및 회복 속도는 각각 48초와 65초로 나타나 매우 빠름을 알 수 있었다. 그 밖에 감습액 중의 공중합체의 농도, 가교제의 양, 가교반응 시간 등이 내수성을 포함한 감습성질에 미치는 영향을 조사하였다.