Pyridines sulfonation

Fluoropyridiniumsulfonates 2 can be synthesized by fluorinating the corresponding pyridine-sulfonic acids or sodium or amine salts with fluorine diluted with nitrogen in acetonitrile, aqueous acetonitrile, or a polyfluoro alcohol.40,41... 

Sulfonation of 2-aminopyridine gives the 5-sulfonic acid exclu-sively.56,109,110 3-Aminopyridine reacts with chlorosulfonic acid to give 3-amino-2-pyridinesulfonic acid (44).103,111 4-Amino-3-pyridine-sulfonic acid is obtained from 4-aminopyridine.112 Arsonation of... 

Phthalic Anhydride 85-44-9 Potassium Fluoride 7789-23-3 Pyridine Sulfonic Acid 34521-19-2... 

Water-insoluble amines are dissolved in a dilute acid, or when necessary in methanol, ethanol, acetone, or even pyridine. Sulfonic acids are used as their sodium salts. If there is a danger that the amine may undergo more than single coupling when this is not desired, then,... 

Ketone, aromatic nitrate, tertiary amine, pyridine, sulfone, trialkyl phosphate or phosphine oxide + 0 + + 0 + +... 

N-methylation, 766 from 3-nitraminopyridine, 702 from 5-nitramino-2-pyridine-sulfonic acid, 704 nitration, 2, 809 rate of bromide substitution in [Pt(dien)Brl+, 849 reaction with, amino acids,... 

Several materials have been proposed and commercialized as electrolytes for HT-PEFCs. As introduced before, the main polymers used materials from the PBI family and the Advent tetramethyl pyridine sulfone (TPS) family, both being basic polymers allowing chemical interaction with mineral acids (e.g., phosphoric acid) see Fig. 1. Differences can be fotmd both in the chemistry and in the synthetic process especially among the different PBIs, yielding different physicochemical properties such as glass transition temperatures, mechanical stabilities, proton conductivities, and achievable phosphoric acid doping levels (defined as either the ratio of phosphoric acid molecules per polymer repeat unit or the weight ratio of polymer and included phosphoric acid) for a summary, see Table 1. 

MitA pyridine sulfonic acids [Ni(3-CsH4N-S03)2(H20)4] 294 3.24 Gouy distorted octahedral 72Q, 72A15... 

Calcium Pyridine Sulfonate - 100-150 38-66 - E - — plus 1 5 percent HjSO, and a trace of HgSOd Alloy C = O.I mpy... 

Although these explanations were based upon reasonable assumptions, some observations can still not be accounted for, and Julia admitted that other reaction pathways might be followed in specific cases, such as in the coupling of BT-sulfones with arylaldehydes. To rationalize these anomalous results, Sylvestre Julia invoked the participation of benzyl-type carbocations followed by El-type elimination. Finally, S. Julia et al. studied the elimination of jS-hydroxy pyridinic sulfones and observed results analogous to those reported for the BT-sulfone derivatives (Scheme 3.44). 

Electron-deficient as well as electron-rich aryl boronic acids proved to be competent partners in the reaction, but electron-deficient boronic acids required higher temperatures. Boronic acids containing aryl halides (I, Cl) were also competent partners, providing a functional handle for further elaboration. Both primary and secondary amines have been utilised as coupling partners. A limitation of this chemistry is the inability to use nitrogen-based heterocycles due to either protodeboronation or the instability of the electron-poor sulfonyl chloride intermediate. Buchwald and coworkers later found that pyridylzinc reagents could be coupled with 2,4,6-trichlorophenyl chlorosulfate (TCPC) to access pyridine sulfonates without a transition metal catalyst." The pyridine sulfonates were subsequently treated with amines to generate sulfonamides. 

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