Pyridinium-l-sulfonate

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

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

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

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

Sulfonation of indole with pyridinium-A -sulfonate yields indolyl-3-sulfonic acid, and bromine in pyridine at 0 °C affords 3-bromoindole (Scheme 7.4). Acetylation with a heated mixture of acetic anhydride and acetic acid gives 1,3-diacetylindole. Methylation requires heating with methyl iodide in DMF (A,A-dimethylformamide) at 80-90 C and yields 3-methylindole. This compound reacts further, giving 2,3-dimethylindole and finally l,2,3,3-tetramethyl-3Ff-indoleninium iodide. 

J 2 = l-fluoro-4,6-bis(trifluoromethyl)pyridinium 2-sulfonate 3=l-fluoro-2.4,6-lrimethylpyridinium trifluoroinethanesulfonate. 

Dicarbonyl compounds are selectively fluorinated a to the two carbonyl groups with 1-fluoro-4.6-bis(trifluoromethyl)pyridinium 2-sulfonate (2) at room temperature. In sharp contrast, the fluorination of carbonyl compounds with l-fluoro-2,4,6-trimethylpyridinium trifluoro-methanesulfonate (3) requires heating and Lewis acid catalysis (Table 6). The reactivity of the pyridinium N-F reagent is dependent on the electronic nature of the substituents on the ring.41 When two equivalents of. V-fluoropyridinium salts were used for the fluorination of 1,3-dicarbonyl compounds, the major product was the 2,2-difluoro derivate (Table 7). 

The first is fluorination of cyclopenta[c]thiophene-4,6-dione 106 by treatment with A-fluoro-6-(trifluoromethyl)pyridinium-2-sulfonate (MEC-04B) in ethyl acetate to give l,3-dibromo-5,5-difluorocyclopenta[c]thiophene-4,6-dione 107 in 84 % yield. Then, conversion of the two carbonyl groups to difluoromethylene groups was accomplished via formation of the bis-l,3-dithiolane derivative 108 followed by desulfurative fluorination with hydrofluoric acid-pyridine complex and dibromatin (l,3-dibromo-5,5-dimethylhydantoin) in dichloromethane to afford 1,3-dibromohe xafluorocyclopenta[c]thiophene 109 in a two-step yield of 73 % [Id, 67]. 

N,N-dimethyl(3-myristoylaminopropyl)ammonio]propanesulfon-ate (Amidosulfobetaine-14) l-(3-Sulfopropyl)pyridinium betaine 3-Dodecyldimethylammoniopropane-l-sulfonate 3-[(3-cholamidopropyl)dimethylammonio]-l-propanesulfonate Lauryl betaine Cocamidopropyl betaine n-d odecyl-N,N-d imethylglycine Tallowglycine Perfluorooctanesulfonate Perfluorinated carboxylic acids Perfluorooctanoic acid Fluorinated telomere alcohols Acetylene diols Acetylene diol alkoxylates Acetylene glycols... 

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]. 

To a solution of 1.5 gm (0.0104 mole) of j8-naphthol in 100 ml of dry benzene containing 1.7 ml of dry pyridine maintained at 55°C is added a solution of 4.3 gm (0.103 mole) of p-n-decyloxybenzenediazonium toluene-p-sulfonate in 50 ml of dry benzene maintained at 60°C. The mixture is kept overnight. Then the precipitated pyridinium toluene-p-sulfonate is filtered off. The filtrate is cautiously evaporated to dryness. On recrystallization of the residue from ethanol, 3.4 gm of l-(p- -decyloxyphenylazo)-2-naphthol is isolated, m.p. 73°-76°C, yield 85 %. On further recrystallization the melting point may be raised to 78°-79°C. 

PDADMA = poly(diallyldimethylammonium chloride) a positively, PSS = poly(styrenesulfonic acid), PAMPS = poly(2-acrylamido-2-methyl-l-propane sulfonic acid), and PFPVP = 4-vinyl-trideca-fluoro-octyl pyridinium iodide-co-4-vinyl pyridine. 

In contrast to the ease of N-functionalization, shown in Scheme 1, the triazolopyridine nucleus is resistant to direct nuclear oxidation or electrophilic additions. Electrophilic additions will occur on aryl substituents for example, nitration of l-phenyltriazolo[4,5-c]pyridine (26) and sulfonation of 2-phenyl-2i/-triazolo[4,5-6]pyridine (28) occur exclusively in the para position of the phenyl ring <34LA(514)279, 38MI 710-01). Nuclear functionalization was observed when l-( -butyl)-5-methyl-tri-azolo[4,5-c]pyridinium iodide (30) was treated with potassium ferricyanide to afford triazolopyridin-4-one (31), as shown in Scheme 2. Similarly, the iodide (30) is converted by either phosphorus oxychloride-phosphorus pentachloride, or bromine or nitric acid to 7-substituted triazolopyridin-4-ones (32) <37LA(529)288>. 

Our final example is a base-labile 4-(phenylsulfonyl)methyl-l,3-dioxolane protecting group for aldehydes and ketones.4 Protection is carried out by the reaction of diol 17,1 (obtained by dihydroxylation of ally phenyl sulfone) with a carbonyl compound in the presence of pyridinium p-toluene sulfonate [Scheme 2.17], Cleavage is accomplished by treatment with DBU. /erf-Butyldimethylsilyl ethers, p-toluenesulfonate esters, tetrahydropyranyl ethers, carboxylic esters and benzoates are well tolerated. A disadvantage to the use of 17.1 is the introduc-... 

The 2-halo-substituted benzimidazoles, then, more or less readily react with ammonia, amines and hydrazines (80AHC 27)241,70AHC(12)103,74CRV279), It is likely that the formation of the 2-pyridinium compound (123) when cycloheptimidazolin-2(l//)-one reacts with phosphoryl chloride in pyridine occurs via the 2-chloro intermediate (Scheme 56). The sulfur function of benzimidazole-2-sulfonic acid can be displaced by amino or alkylamino groups. 

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