• 제목/요약/키워드: Substituted pyrroles

검색결과 11건 처리시간 0.023초

Facile Regiocontrolled Three-Step Synthesis of Poly-Substituted Furans, Pyrroles, and Thiophenes: Consecutive Michael Addition of Methyl Cyanoacetate to α,β-Enone, CuI-Mediated Aerobic Oxidation, and Acid-Catalyzed Paal-Knorr Synthesis

  • Kim, Se-Hee;Lim, Jin-Woo;Lim, Cheol-Hee;Kim, Jae-Nyoung
    • Bulletin of the Korean Chemical Society
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    • 제33권2호
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    • pp.620-624
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    • 2012
  • An efficient synthesis of poly-substituted furans, pyrroles, and thiophenes was carried out in a regiocontrolled manner via a three-step process; (i) conjugate addition of methyl cyanoacetate derivatives to ${\alpha}$,${\beta}$-enones, (ii) CuI-mediated aerobic oxidation, and (iii) Paal-Knorr type synthesis of five-membered heterocycles.

1,4-디클로로-1,4-디메톡시부탄올 이용한 카르바졸의 합성 (The Carbazole Synthesis From 1,4-Dichloro-1,4-dimethoxybutane)

  • 정봉영;배덕종;진정일;이승달
    • 대한화학회지
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    • 제36권4호
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    • pp.603-605
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    • 1992
  • 1,4-Dichloro-1,4-dimethoxybutane과 일차 아민 또는 아미드를 약 염기성인 Amberlyst A-21 resin 존재하에서 반응시켜 N-치환된 피롤을 합성하였으며, 이 피롤 화합물에 1,4-dichloro-1,4-dimethoxybutane를 다시 반응시켜 N-치환된 카르바졸을 합성하였다.

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The Mechanisms for Thermal and Photochemical Isomerizations of N-Substituted 2-Halopyrroles: Syntheses of N-Substituted 3-Halopyrroles

  • Park, Sung-Hyun;Ha, Hong-Joo;Lim, Chul-Taek;Lim, Dong-Kwon;Lee, Kwang-Hee;Park, Yong-Tae
    • Bulletin of the Korean Chemical Society
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    • 제26권8호
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    • pp.1190-1196
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    • 2005
  • Halopyrroles, N-substituted 2-halopyrroles were prepared by halogenation of N-substituted pyrroles with NBS, NCS, or surfuryl chloride. N-Substituted 3-halopyrroles were synthesized by acid-catalyzed thermal and photochemical isomerization reactions of N-substituted 2-halopyrroles. Both the thermal and photochemical reactions were acid-catalyzed. For the acid-catalyzed isomerization, a mechanism of [1,3] bromine shift followed by deprotonation is operated. For the acid-catalyzed photoisomerization, an excited triplet state of 2-protonated N-benzyl-2-halopyrrole produces an intermediate N-substituted pyrrole complex with halonium ion which is equilibrated with N-substituted pyrrole plus halonium ion, and then the halonium ion newly adds to 3-position of N-substituted pyrrole followed by deprotonation to afford N-benzyl-3-halopyrrole.

Thallium(I)-Selective Electrodes Based on Calix[4]pyrroles

  • 박경순;정성욱;이심성;김재상
    • Bulletin of the Korean Chemical Society
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    • 제21권9호
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    • pp.909-912
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    • 2000
  • Thallium(I) selective electrodes based on meso-alkyl substituted calix[4]pyrroles such as, meso-octamethyl-calix[4]pyrrole (L1), meso-octaethylcalix[4]pyrrole (L2) and meso-tetraspirocyclohexylcalix[4]pyrrole (L3) as sensor molecules have been pre pared and tested. The conditioned electrode (E4) incorporating L3gave best results with a wide working concentration range of 10-5.5 ~10-1 M near-Nernstian slope of 56.0 mV/decade of activity and detection limit of 10-6.0 M. This electrode exhibited a fast response time of 30 s and high selectivity over Na+ , K+ and other metal ions with only Ag+ interfering. The electrode works well in the pH range 2.0-11.0 and can be successfully employed for the determination of Tl+.This proposed electrode was also used as an indicator electrode in potentiometric titration of Tl+.

Synthesis of a small molecular cage consisting of three aminomethyl pyrroles and its selective fluoride recognition

  • Nam Jung, Heo;Hye Jin, Han;Jaewon, Choi;Sung Kuk, Kim
    • 한국자기공명학회논문지
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    • 제26권4호
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    • pp.40-45
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    • 2022
  • A small cage-like molecule (2) composed of three aminomethyl pyrroles and two hexa-substituted benzenes has been prepared by reduction of its iminopyrrole analogue (1) using NaBH4. It was revealed by 1H NMR spectroscopic analyses that cage molecule 2 strongly binds the fluoride anion in polar DMSO-d6 relative to CDCl3. Compared to that of compound 1, the lowered affinity of 2 for the fluoride anion is attributable to its increased electron density resulting from the production of thesecondary amine groups.

配置와 形態에 관한 分子軌道函數論的 硏究 (第3報). Furan, Thiophene 및 Pyrrole 카르보닐 化合物의 2-置換體의 形態 (MO Studies of Configuration and Conformation (Ⅲ). Conformations of Some 2-Substituted Furan, Thiophene and Pyrrole Carbonyl Compounds)

  • 이익춘;김시준
    • 대한화학회지
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    • 제21권1호
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    • pp.32-37
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    • 1977
  • EHT 분자궤도함수법 계산으로 9가지 furan, thiophene 및 pyrrole의 2-치환체의 우세한 형태를 구명하였다. 계산 결과는 furan 유도체의 우세한 형태는 trans형인데 이것은 주로 정전기적 상호작용에 의하여 안정화되어 있으며 thiophene에서는 hetero 고리의 S원자와 카르보닐 산소와의 전자적 콘쥬게이션이, 그리고 pyrrole에서는 정전기적 및 콘쥬게이션 효과가 안정한 형태를 결정하는데 작용하고 있다. EHT계산 결과는 실험결과와도 잘 일치된다.

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meso-Substituted Dipyrromethanes from Vinylogous Aromatic Heterocycles and Their Utilization to the Synthesis of meso-Functionalized Porphyrins

  • Hong, Seong-Jin;Lee, Mi-Hye;Lee, Chang-Hee
    • Bulletin of the Korean Chemical Society
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    • 제25권10호
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    • pp.1545-1550
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    • 2004
  • meso-Functionalized dipyrromethanes 6-10 were synthesized by acid-catalyzed addition of pyrrole to ${\alpha}$-position of 2-alkenyl pyrroles. The regiochemistry of the reaction can be explained by either the formation of more stable carbocation intermediate or ${\beta}$-addition of ${\alpha},{\beta}$-unsaturated carbonyl compounds. The starting 2-alkenyl pyrroles were synthesized by Aldol condensation of 2-formylpyrrole with active methylene compounds such as nitromethane, diethylmalonate and malononitrile. Attempted ‘2+2' condensation of meso-diethylmalonyldipyrromethane, meso-(p-tolyl)dipyrromethane and p-tolualdehyde afforded three different porphyrins 12, 13 and 14 in reasonable yields. On the other hand, meso-(nitromethyl)dipyrromethane with p-(tbutyl) benzaldehyde resulted in the formation of three different porphyrins such as 5,15-dicyano-10,20-diarylporphyrin (16), 5-cyano-15-formyl-10,20-diarylporphyrin (17) and 5,15-diformyl-10,20-diarylporphyrin (18) in low yields. Conversion of nitromethyl groups to nitrile and (or) formyl group was observed under the porphyrin forming conditions.