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Bromination Reaction of Methyl Pyropheophorbide--a
Wang, Jinjun,Han, Guangfan,Wu, Xuran,Wang, Lumin,Shen, Rongji CHINESE MEDICAL ASSOCIATION 2004 CHINESE JOURNAL OF ORGANIC CHEMISTRY Vol.24 No.5
<P>Methyl pyropheophorbide-a (MPP-a) was used as starting material for the synthesis of new bromine-substituted chlorin compounds. The bromines were introduced into 3-position and meso-position of the chlorin chromophore by addition reaction and substitution reaction with the bromide reagents to give mono-bromine- and tri-bromine-substituted chlorines. The formal addition product, hydrolyzate and esterified product were obtained by addition reaction with 30% hydrogen bromide in acetic acid. MPP-a was oxidized with OsO<SUB>4</SUB> in THF containing catalytic pyridine at 0 ℃, and followed by glycol cleavage with sodium periodate in aqueous THF to give the methyl pyropheophorbide- d (MPP-d) which was reacted with carbon tetrabromide and triphenylphosphine to generate gem-dibromine substituted product at 3~b-position. The structures of all new compounds were characterized by elemental analysis, UV, IR and ]H NMR spectra.</P>
Tsurumaki, Eiji,Inokuma, Yasuhide,Easwaramoorthi, Shanmugam,Lim, Jong Min,Kim, Dongho,Osuka, Atsuhiro WILEY-VCH Verlag 2009 Chemistry Vol.15 No.1
<P>Effective peripheral fabrication methods of meso-aryl-substituted subporphyrins were explored for the first time. Hexabrominated subporphyrins 2 were prepared quantitatively from the bromination of subporphyrins 1 with bromine. Hexaphenylated subporphyrins 3 and hexaethynylated subporphyrins 4 and 5 were synthesized by Suzuki–Miyaura coupling and Stille coupling, respectively, in good yields. X-ray crystal structures of 2 b, 3 b, 4 b, and 5 a revealed preservation of the bowl-shaped bent structures with bowl depths similar to that of 1. Hexaethynylated subporphyrins exhibit large two-photon-absorption cross-sections due to effective delocalization of the conjugated network to the ethynyl substituents.</P> <B>Graphic Abstract</B> <P>β-Substituted subporphyrins: β-Hexabrominated, hexaphenylated, and hexaethynylated (see picture) meso-aryl subporphyrins are reported as the first products of β-peripherally fabricated subporphyrins. X-ray diffraction analysis revealed that all hexasubstituted subporphyrins preserve bowl-shaped structures. Detailed NMR, electrochemical, optical, and theoretical studies were carried out. <img src='wiley_img/09476539-2009-15-1-CHEM200801802-content.gif' alt='wiley_img/09476539-2009-15-1-CHEM200801802-content'> </P>
Jinchang Liu,Hiroki Shimanoe,Jong‑Eun Choi,Seunghyun Ko,Young‑Pyo Jeon,Koji Nakabayashi,Jin Miyawaki,Seong‑Ho Yoon 한국탄소학회 2019 Carbon Letters Vol.29 No.2
Pitch precursors affording excellent spinnability, high-level oxidation-resistance, and good carbonization yields were prepared by bromination–dehydrobromination of various ratios of pyrolyzed fuel oil and coal tar pitch. The pitches exhibited spinnabilities that were much better than those of pitches prepared via simple distillation. A pitch prepared using a 1:2 ratio of fuel oil and coal tar pitch exhibited the best tensile strength. Pitch fibers of diameter 8.9 ± 0.1 μm were stabilized at 270 °C without soaking time after heating at a rate of 0.5 °C/min and carbonized at 1100 °C for 1 h after heating at 5 °C/min. The resulting carbon fibers exhibited a tensile strength, elongation, Young’s modulus, and average diameter of 1700 ± 170 MPa, 1.6 ± 0.1%, 106 ± 37 GPa, and 7.1 ± 0.2 μm, respectively.
차민석,오성근,홍영택,이장용 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
The most recent studies to produce anion exchange materials has greatly favored the bromination reaction, one of conventional methods for introducing cationic group. The main advantage of the bromination reaction is that it allows for a nearly quantitative conversion of precursors as well as fast reaction rates. However, various limitations of bromination reaction still existed such as unpredictable dibromination and chain scission. Accordingly, our research focused on overcoming the limitation of bromination reaction by controlling reaction conditions. Herein, a series of polymer containing a benzyl bromide group were synthesized using bromination reaction under various reaction condition. In particular, we measured a nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography and physical properties of synthesized polymer.
김건주,정호영,김민우,조민선,신동석 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1
The polymer electrolyte based on brominated poly(2,6-dimethyl-1,4- phenylene oxide(bPPO) containing 1-methylimidazole was prepared for fuel cells. However, according conditions, bromination degree of the brominated poly(2,6-dimethyl-1,4-phenylene oxide(bPPO) is changed and it caused high cell performance. The ionic conductivity, water uptake, dimensional change and IEC of brominated poly(2,6-dimethyl- 1,4-phenylene oxide(bPPO) membrane is fairly changed depending on pendant containing 1-methylimidazole groups in the membrane. Therefore, discovering the ideal conditions about preparation of bPPO+Im is going to be useful for increasing cells capability and operating fuel cells.
박명숙,권순경 德成女子大學校 藥學硏究所 1999 藥學論文誌 Vol.10 No.1
2-Bromo monosubstituent of 3,4-methylenedioxybenzoic acids was obtained from selective bromination in the presence of bromine in glacial acetic acid. Reaction was sucessfully proceeded through stirring of glacial acetic acid after dropwise over 4 h 100mol% of bromine and acetic acid at room temperature for 18 h. 2-Position rather than 6-position of aromatic nucleus was substituted first during bromination, and thereafter 2,6-disubstituted analogue followed even though steric hindrance.
Guojun Pan,Ke Yang,Yantao Ma,Xia Zhao,Kui Lu,Peng Yu 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.5
C-6 and C-8 monobromo flavonoids are important building blocks for the synthesis of flavonoid natural products and their derivatives. Bromination of suitably alkylated flavonoids with N-bromosuccinimide in dichloromethane (DCM), followed by deprotection with BCl3, gives either a C-6 or a C-8 monobromo flavonoid in high yield and with high regioselectivity, depending on the protection pattern of the C-5 and C-7 OH groups. The mild and neutral conditions are particularly useful for the regioselective bromination of acid-labile substrates.
Alinezhad, Heshmatollah,Tajbakhsh, Mahmood,Tehrani, Shahram Shahriari Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.5
N-Bromosaccharin/$Mg(ClO_4)_2$ is an effective and regioselective system for ${\alpha}$-monobromination of 1,3-dicarbonyl compounds. A wide variety of ${\beta}$-keto esters and 1,3-diketones in reaction with this system afforded a regioselectively ${\alpha}$-monobrominated products. The bromination reaction can be conducted at 0-5 $^{\circ}C$ either in solution or under solvent-free conditions.