Pyridinium-1-sulfonate

Yohino, T, Sato, K, Wanme, F, Takai, I, Ishido, Y, Efficient catalysis by pyridinium sulfonate in glycosylation involving an oxazoline intermediate derived from per-O-acetyl-iV-acetyllactosamine and A,V-diacetylchitobiose, Glycoconjugate J., 9, 287-291, 1992. 

Sulfonyl chlorides. Sulfonic acids can be converted in satisfactory yield into sulfonyl chlorides via pyridinium sulfonates. Aminobenzenesulfonic acids can be converted quantitatively into pyridinium acetamidobenzenesulfonates by... 

Acid-catalysed esterification reactions in ILs have been extensively studied, and will be the main focus of this section. In 2001, Deng et al. first reported the synthesis of allq l acetate esters in an IL with concentrated sulfuric acid as the acid catalyst (Scheme 3.7). The majority of subsequent studies, however, have switched away from an IL with an added acid catalyst and towards Bronsted acid ionic liquids (BAILs) - a type of task-specific ionic liquid. BAILS incorporate an acidic moiety (typically either a sulfonic acid or a protonated nitrogen) on the cation allowing the BAILS to have dual functionality as both a solvent and a catalyst. There are several different classes of BAILs that have been applied to esterifications such as imidazo-lium 1, imidazolium sulfonic 2, phosphonium sulfonic 3, pyridinium sulfonic 4, quaternary ammonium 5, quaternary ammonium sulfonic 6 and lactam 7 based-BAILs (Scheme 3.8). 

Fig. XI-13. Adsorption isotherms for SNBS (sodium p-3-nonylbenzene sulfonate) (pH 4.1) and DPC (dodecyl pyridinium chloride) (pH 8.0) on mtile at approximately the same surface potential and NaCl concentration of O.OlAf showing the four regimes of surfactant adsorption behavior, from Ref. 175. [Reprinted with permission from Luuk K. Koopal, Ellen M. Lee, and Marcel R. Bohmer, J. Colloid Interface Science, 170, 85-97 (1995). Copyright Academic Press.]...

Pyridinium sulfate, bis-l,2,4,6-tetramethyl-hydrogen isotope exchange reactions, 2, 194 Pyridinium-1 -sulfonates reactions, 2, 34... 

The C2-symmetric epoxide 23 (Scheme 7) reacts smoothly with carbon nucleophiles. For example, treatment of 23 with lithium dimethylcuprate proceeds with inversion of configuration, resulting in the formation of alcohol 28. An important consequence of the C2 symmetry of 23 is that the attack of the organometallic reagent upon either one of the two epoxide carbons produces the same product. After simultaneous hydrogenolysis of the two benzyl ethers in 28, protection of the 1,2-diol as an acetonide ring can be easily achieved by the use of 2,2-dimethoxypropane and camphor-sulfonic acid (CSA). It is necessary to briefly expose the crude product from the latter reaction to methanol and CSA so that the mixed acyclic ketal can be cleaved (see 29—>30). Oxidation of alcohol 30 with pyridinium chlorochromate (PCC) provides alde-... 

The preparation of N-(4-pyridyl)pyridinium chloride hydrochloride follows the procedure of Koenigs and Greiner,6 while the preparation of the sulfonic acid is a modification of a patent procedure.13... 

CH2)2SiMe2-C6H4- (p-CHO) Tg[(CH2)2-SiMe2-C6H4-(p-CH(-OCH2CH2-0-))]g+pyridinium toluene sulfonate — — 204... 

Alkyl halides or sulfuric or sulfonic esters can be heated with sodium or potassium thiocyanate to give alkyl thiocyanates, though the attack by the analogous cyanate ion (10-66) gives exclusive N-alkylation. Primary amines can be converted to thiocyanates by the Katritzky pyrylium-pyridinium method (pp. 447, 489). "... 

Pyridinium-1-sulfonate was prepared according to the procedure of Sisler and Audrieth. The submitter reports that this procedure may be conveniently carried out at 5 times the specified scale. The reagent should be dry and used soon after its preparation. The checkers found that a technical grade of pyridinium-1-sulfonate (sulfur trioxide pyridine complex) purchased from Aldrich Chemical Company, Inc., gave substantially lower yields of product. 

Glutaconaldehyde (8) 2-Pentenedial (9) (821-42-1) Glutaconaldehyde, sodium salt, dihydrate Glutaconaldehyde, ion (1 ) sodium (8) 2-Pentenedial, ion (1 ), sodium (9) (24290-36-6) Pyridinium-1-sulfonate Pyridinium, 1-sulfo-, hydroxide, inner salt (8,9) (42824-16-8)... 

FLUORIDE, 58, 75 Pyridinium-l-sulfonate, 59, 79 hydrolysis to glutaconaldehyde sodium salt, 59,79... 

GLUTACONALDEHYDE SODIUM SALT FROM HYDROLYSIS OF PYRIDINIUM-l-SULFONATE... 

In a 500-ml., three-necked, round-bottomed flask fitted with a mechanical stirrer and a thermometer is placed 42 g. (1.05 mole) of sodium hydroxide dissolved in 168 ml. of water. The contents of the flask are cooled to —20° and stirred vigorously as 48 g. (0.30 mole) of pyridinium-1-sulfonate (Note 1), which has been previously chilled to — 20°, is added in one portion. The mixture is stirred for 20 minutes while the temperature is kept below —5° (Note 2). The cooling bath is removed, and the mixture is stirred and warmed gradually to 20° over 20 minutes. The temperature of the dark orange mixture is then raised to 55-60° and after 1 hour is lowered again to —5°. The brown crystals that separate are filtered by suction, pressed into a compact filter cake, and washed with three 100-ml. portions of acetone (Note 3). The yield of this crude product amounts to 46-52 g. after drying on filter paper overnight or at 50° (1 mm.) for 1 hour. (Note 4). 

Most studies of micellar systems have been carried out on synthetic surfactants where the polar or ionic head group may be cationic, e.g. an ammonium or pyridinium ion, anionic, e.g. a carboxylate, sulfate or sulfonate ion, non-ionic, e.g. hydroxy-compound, or zwitterionic, e.g. an amine oxide or a carboxylate or sulfonate betaine. Surfactants are often given trivial or trade names, and abbreviations based on either trivial or systematic names are freely used (Fendler and Fendler, 1975). Many commercial surfactants are mixtures so that purity can be a major problem. In addition, some surfactants, e.g. monoalkyl sulfates, decompose slowly in aqueous solution. Some examples of surfactants are given in Table 1, together with values of the critical micelle concentration, cmc. This is the surfactant concentration at the onset of micellization (Mukerjee and Mysels, 1970) and can therefore be taken to be the maximum concentration of monomeric surfactant in a solution (Menger and Portnoy, 1967). Its value is related to the change of free energy on micellization (Fendler and Fendler, 1975 Lindman and Wennerstrom, 1980). 

Polyvinyl alcohol Polystyrene sulfonate Polyvinyl pyridinium... 

The separation of the same charged compounds were also accomplished on an ethyl-pyridine bonded silica surface and 30 0% methanol/C02 mobile phases without the need of added sulfonate modifier. Anionic compounds did not elute from the ethyl-pyridinium surface that lead the authors to hypothesize that the surface was positively charged. To further test this hypothesis, the separation of the same compounds on a strong anion exchange column, silica-based propyltri-methylammonium cationic surface, which exhibits are permanent positive charge was attempted. The same retention order was observed on the strong cation exchange surface. 

Silylcuprates have been reported to undergo reactions with a number of miscellaneous Michael acceptors [65]. Conjugate addition to 3-carbomethoxy acyl pyri-dinium salts [65a] affords 4-silyl-l,4-dihydropyridines. Oxidation with p-chlorand generates a 4-acyl pyridinium salt that gives the 4-silylnicotinate upon quenching with water, and methyl 4-silyl-2-substituted dihydronicotinates upon quenching with nucleophiles (nucleophilic addition at the 6-position). The stabilized anion formed by conjugate addition to an a, j8-unsaturated sulfone could be trapped intramolecularly by an alkyl chloride [65b]. 

Acetals and ketals are very important protecting groups in solution-phase synthesis, but only a few constructs have been used as linkers in solid-phase synthesis (Tab. 3.3). The THP-linker (22) (tetrahydropyran) was introduced by Ellman [54] in order to provide a linker allowing the protection of alcohols, phenols and nitrogen functionalities in the presence of pyridinium toluene sulfonate, and the resulting structures are stable towards strong bases and nucleophiles. Other acetal-linkers have also been used for the attachment of alcohols [55, 56]. Formation of diastereomers caused by the chirality of these linkers is certainly a drawback. Other ketal tinkers tike... 

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