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Polymers
Published in Bryan Ellis, Ray Smith, Polymers, 2008
Polym. Chem., 1965, 3, 2885, (H-1 nmr) U.S. Pat., 1951, 2 555 179, (boron trifluoride-etherate catalyst)U.S. Pat., 1960, 2 962 476, (stabilisation)U.S. Pat., 1965, 3 201 366, (stabilisation)U.S. Pat., 1963, 3 080 352, (boron trifluoride-etherate catalyst)Ger. Pat., 1960, 1 084 918, (bimetallic catalysts)Ger. Pat., 1958, 1 091 754, (Friedel-Crafts type catalysts)Brit. Pat., 1948, 610 203, (boron trifluoride-etherate system)Brit. Pat., 1960, 846 690, (iron hydrosulfate catalyst)
Macrocyclic Receptors Synthesis, History, Binding Mechanism: An Update on Current Status
Published in Satish Kumar, Priya Ranjan Sahoo, Violet Rajeshwari Macwan, Jaspreet Kaur, Mukesh, Rachana Sahney, Macrocyclic Receptors for Environmental and Biosensing Applications, 2022
Satish Kumar, Priya Ranjan Sahoo, Violet Rajeshwari Macwan, Jaspreet Kaur, Mukesh, Rachana Sahney
Ma et al. synthesized a cationic water-soluble pillar[5]arene receptor 60 in two synthetic steps (Scheme 37) (Ma et al. 2011). The reaction with paraformaldehyde in the presence of boron trifluoride etherate yielded an intermediate in 41% yield. The receptor contains trimethylammonium moiety at both ends of pillar[5] arene and was isolated as a colorless solid with 95% yield. It also formed a 1:1 pillar[5]arene-sodium 1-octanesulfonate supramolecular complex in aqueous media. Both hydrophobic and electrostatic interactions played a major role during supramolecular complexation.
Polysaccharides
Published in Stanislaw Penczek, H. R. Kricheldorf, A. Le Borgne, N. Spassky, T. Uryu, P. Klosinski, Models of Biopolymers by Ring-Opening Polymerization, 2018
Polymerization with triethyloxonium tetrafluoroborate catalyst affords a polymer with the lowest specific rotation +22.5°, which is almost the same as that proposed by Micheel et al. Such catalysts as boron trifluoride etherate, trifluoromethanesulfonic acid, and trimethanesulfonic anhydride were also active.8
An environmentally benign, simple and proficient synthesis of quinoline derivatives catalyzed by FeCl3.6H2O as a green and readily available catalyst
Published in Green Chemistry Letters and Reviews, 2021
S. Tasqeeruddin, Yahya I. Asiri, S. Shaheen
As a consequence of the tremendous medicinal and industrial application of quinoline derivatives, chemists have discovered a plethora of methods to elaborate the structure of quinoline scaffolds includes Skraup (16), Conrad-Limpach-Knorr (17), Pfitzinger (18), Friedlander (19), and Friedlander condensation (20–22). Various new methods have also been developed which employed metallic or organometallic reagents such as CuCN, LiCl (23). Ruthenium (III) chloride RuCl3.nH2O/3PPh3 (24), Ytterbium (III) triflate Yb(OTf)3 (25), Tungsten vinylidene complex W(CO)5(THF) (26), Boron trifluoride etherate BF3.OEt2 (27, 28), Benzotriazoleiminium salts (29), etc. for the synthesis of quinoline derivatives. Regardless of the many merits reported by these methods, they are also plagued by limitations like poor yields, difficult work-up, and effluent pollution. Nowadays, sustainable chemistry is receiving much attention due to resource challenge, the climate and the environmental challenge. Therefore, it is aimed to develop simple and facile methods to carry organic synthesis under mild conditions (30).
Synthesis, structure and reactivity of some chiral benzylthio alcohols, 1,3-oxathiolanes and their S-oxides
Published in Journal of Sulfur Chemistry, 2020
R. Alan Aitken, Philip Lightfoot, Andrew W. Thomas
The chiral mercapto alcohol 6 is a member of a potentially useful but uncommon class of compounds, although it might be noted that there is one paper [9] involving use of the isopropyl analogue derived from (S)-valine as a chiral auxiliary. We realized that reaction of compound 6 with aldehydes would give a range of chiral 2,4-disubstituted-1,3-oxathiolanes. The stereoselectivity of the ring closure process, leading to cis and trans isomers, is of interest and, after S-oxidation, there is one report of such an (achiral) system acting as a formyl anion equivalent [10]. Substituted 1,3-oxathiolanes have been prepared in a variety of ways including by 1,3-dipolar cycloaddition, either of carbonyl ylides to thioketones [11], or of thiocarbonyl ylides to carbonyl compounds [12,13]. Reaction of compound 6 with pivalaldehyde and benzaldehyde in boiling diethyl ether with addition of boron trifluoride etherate gave the 1,3-oxathiolanes 16 and 17, respectively, in high yield as inseparable mixtures of diastereomers. In the case of phenylgloxal, reaction with 6 catalysed by p-toluenesulfonic acid in toluene gave the diastereomers 18a and 18b which were separated by chromatography (Scheme 4).
Strategies for introducing sulfur atom in a sugar ring: synthesis of 5-thioaldopyranoses and their NMR data
Published in Journal of Sulfur Chemistry, 2019
Kuszmann and colleagues [149], explored the synthesis of various 5-thio-l-arabinopyranosides derivatives (Scheme 38). 5-O-tosylate of 2,3-O-isopropylidene-l-arabinose diethyl dithioacetal 222 was utilized as starting material and converted into the corresponding 5-S-benzoate 223 [38]. Demercaptalation of the ethylthio groups of 223 was successfully accomplished with mercuric oxide in the presence of boron trifluoride etherate [150] and the resultant aldehyde 224 was subjected to the debenzoylation step. Surprisingly, migration of the benzoyl group from S-5 to O-4 took place together with the debenzoylation step and the formed free thiol group cyclized simultaneously into a pyranose ring to afford 225 as an anomeric mixture. Acidic hydrolysis of compound 225 gave the monobenzoyl thiopyranose 226 and subsequent saponification of the benzoyl group furnished the globally deprotected of 5-thio-l-arabinopyranose 227. Acetylation of 227 gave the peracetate 228 as a mixture of anomers. On the other hand, methanolysis of compound 225 followed by acetylation of the free diols offered the fully protected methyl pyranoside 229. Deprotection of the acyl groups using NaOMe/MeOH gave the methyl 5-thio-l-arabinopyranoside 230 as mixture of anomers.