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Oxidation Reactions
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
Periodic acid (also called meta-periodic acid) is usually written as HIO4 but also exists as the dihydrate, orthoperiodic acid, written as H5IO6. The structure of both compounds is shown in the figure. The two structures are used interchangeably for the reaction discussed in the following questions.
Synthesis and mesomorphic properties of four ring, rod-like fluorene derivatives – the influence of the lateral substitution on mesomorphic properties of 2,7-bis(4-alkylphenyl)-fluorenes
Published in Liquid Crystals, 2020
Ewelina Dmochowska, Aneta Bombalska, Przemysław Kula
General synthetic methods of compounds 6P-FL-P6; 6P-FL-FPF5; 5FPF-FL-FPF5, 2,7-substituted fluorene derivatives non-substituted at 9th position are given in Figure 2. The synthesis was started from commercially available fluorene (1). At first, fluorene was halogenated with iodine and periodic acid in a mixture of acetic acid, water and sulfuric acid [17]. This electrophilic aromatic substitution reaction with appropriate amounts of iodine and periodic acid gave the main semiproducts 2-iodofluorene (2) and 2,7-diiodofluorene (3) with good yields ca. 50%. The next reaction, Suzuki-Miyaura cross-coupling with (2,3-difluoro-4-pentylphenyl)boronic acid (4) [18] and (4-hexylphenyl)boronic acid (5) (commercially available) gave main products 5FPF-FL-FPF5 and 6P-FL-P6, respectively.
A new stable porous Pr-organic framework constructed by multi-iodine-substituted aromatic polycarboxylates: Synthesis, characterization, and selective adsorption of dyes
Published in Journal of Coordination Chemistry, 2019
Ying Sun, Feng Ying Bai, Xue Min Wang, Yu Wang, Li Xian Sun, Yong Heng Xing
All chemicals purchased commercially were analytical grade or better and used without purification. Solvents were purified according to the standard methods. In particular, praseodymium(III) nitrate hexahydrate, potassium permanganate and pyridine were all purchased from Sinopharm Chemical Reagent Co. Ltd. Mesitylene, iodine and periodic acid were all purchased from Shanghai Boka Chemical Technology Co. Ltd. All IR measurements were obtained using a Bruker AXS TENSOR-27 FT-IR spectrometer with pressed KBr pellets from 400 to 4000 cm−1 at room temperature. Elemental analyses for C, H and N were measured on a Model 240C automatic Perkin-Elmer elemental analyzer. UV–Vis–NIR spectra were recorded on a JASCO V-570 UV/Vis/NIR microspectrophotometer (200–2500 nm). The maximum absorption wavelength of the dye solution was measured on spectrophotometer UV-1000. Thermogravimetric analysis (TG) was performed on a Perkin Elmer Diamond TG/DTA under one atmosphere from room temperature to 1000 °C with a heating rate of 10 °C/min. Powder X-ray diffraction patterns were obtained on a Bruker D8-Advance equipped with Cu–Kα radiation in the range 5° < 2θ < 55°, with a step size of 0.02° (2θ) and a count time of 2 s/step. Atomic force microscope pictures were obtained through an Asylum Research Cypher ES by Oxford Instruments Company.
Novel nematic and glassy liquid crystalline oligomers as electroluminescent organic semiconductors
Published in Liquid Crystals, 2021
Guang Hu, Stephen M. Kelly, Stuart P. Kitney, William Harrison, Brian Lambert
The final product 3,3ʹ-{5ʹ,5ʹ’’-(9,9-dioctyl-9-fluorene-2,7-diyl)bis[(2,2ʹ-bithiophene)-5ʹ,5-diyl]}bis-{9,9-dihexyl-7-[5-(4-methoxyphenyl)thiophen-2-yl]-9-fluorene} (18) was synthesised as shown in reaction scheme 2 according to modified literature methods [30,31]. Commercially available 2-triisopropyl borate was used to treat the reaction mixture after lithiation of 1-bromo-4-methoxybenzene (8) with n-butylithium at −78°C. Then, the mixture was allowed to reach room temperature overnight and acidified with hydrochloric acid to give 4-methoxyphenylboronic acid (9) with an excellent yield 90%. A Suzuki cross-coupling between compound 9 and 2-bromothiophene (10) was carried out using Pd(PPh3)4 as catalyst to afford 2-(4-methoxyphenyl)thiophene (11) in excellent yield (91%). Compound 11 was lithiated with n-butylithium at −78°C and then reacted with commercially available 2-triisopropyl borate. Acidification with hydrochloric acid gave 5-(4-methoxyphenyl)thiophen-2-ylboronic acid (12) in excellent yield (93%). 2-Bromofluorene (13) was iodinated in position 7 with pulverised iodine and periodic acid in acetic acid, concentrated sulphuric acid, and water to afford 2-bromo-7-iodofluorene (14) in moderate yield (68%). 2-Bromo-7-iodo-9,9-dihexylfluorene (15) was synthesised in a one-step procedure from compound 14 using 1-bromohexane, powered potassium hydroxide, potassium iodide, and DMSO as solvent in good yield (75%). A Suzuki aryl-aryl, cross-coupling reaction between compounds 15 and 12 was carried out using Pd(PPh3)4, aqueous K2CO3 and DMF to give compound (16) in moderate yield (65%). Commercially available 2-triisopropyl borate was used to treat the reaction mixture after lithiation of compound 16 with n-butylithium at −78°C. Acidification with hydrochloric acid gave 9,9-dihexyl-7-[5-(4-methoxyphenyl)thiophen-2-yl]-9-fluoren-2-ylboronic acid (17) in good yield (71%). A Suzuki aryl-aryl cross-coupling reaction between compounds 17 and 6 was carried out using Pd(PPh3)4, aqueous K2CO3 and DMF to give the final product (18) in good yield (92%).