4- Pyridine sulfonic acid Organic Compounds

A munber of organic compounds are suitable for use as tracers in a process for monitoring the flow of subterranean fluids. The following traces have been proposed benzene tetracarboxylic acid, methylbenzoic acid, naphthalenesulfonic acid, naphthalenedisulfonic acid, naphthalene-trisulfonic acid, alkyl benzene sulfonic acid, alkyl toluene sulfonic acid, alkyl xylene sulfonic acid, a-olefin sulfonic acid, salts of the foregoing acids, naphthalenediol, aniline, substituted aniline, pyridine, substituted pyridines [883]. 

The first studies on the sulfation of organic compounds, amino acids, and proteins have shown that pyridine/sulfur trioxide complex (pyridine/S03 or pyridine/Cl S03H),168-721 concentrated sulfuric acid,173,74 sulfuric acid//V,A -dicyclohexylcarbodiimide,175,761 and chloro-sulfonic acid177 are the most efficient reagents for the sulfation of tyrosine. More recently, alternative methods based on dimethylformamide/sulfur trioxide complex (DMF/S03),152,781 trimethylamine/sulfur trioxide (Me3N/S03),1152,1531 pyridinium acetylsulfate,137,791 and pyr-idinium trifluoroacetylsulfate1801 have been proposed to minimize side reactions which are difficult to control for the chemical sulfation of tyrosine peptides. 

The method can also be applied to the conversion of 4-chloropyridine (49) to pyridine-4-sulfonic acid (50) (Scheme 28). In compound (49), the chlorine atom is activated to nucleophilic attack by the electron-withdrawing nitrogen atom. Scheme 28 is a useful synthetic sequence since direct sulfonation of pyridine only yields the 3-sulfonic acid as a consequence of the electrophilic nature of the nitrogen atom. Sulfonic acids can also be obtained by oxidation of sulfides, disulfides and sulfinic acids. The introduction of a sulfonic acid group into an organic molecule provides a useful method of increasing the aqueous solubility of the compound. Many sulfonic acids as their sodium salts are... 

In view of this affinity of S in S03 for electrons, it is not surprising that S03 functions as a fairly strong Lewis acid toward those bases that it does not preferentially oxidize. Thus the trioxide gives crystalline complexes with pyridine, trimethylamine or dioxane, which can be used, like S03 itself, as sulfonating agents for organic compounds.583... 

Dioxane-sulfur trioxide is stable at room temperature under anhydrous conditions but is decomposed on heating to 75° in carbon tetrachloride. It is much more reactive than is pyridine-sulfur trioxide and is hydrolyzed instantly by water to form sulfuric acid and dioxane. Its use as a sulfonating agent for a wide variety of organic compounds has been the subject of an extensive investigation by Suter, Evans, and Kiefer. ... 

Presently, many organic additives fall into the category of polymerizable monomers. A non-exhaustive list includes esters (including carboxylic esters/carbonates and other inorganic esters such as phosphates, sulfates, and silicates) that are derived from vinyl and allyl alcohols [2,54,71], vinyl pyridine [63], acrylic acid nitrile [110], maleic acid derivatives [125, 131], vinyl sulfones [128], vinyl silanes [113], and isocyanates [65, 171] (Fig. 2). The synergistic effect of different unsaturated compounds used in various combinations has also been reported [1]. 

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