Quaternary pyridinium complex

The pyridine used in the submitters procedures apparently reacts with the sulfuryl chloride to form an intermediate quaternary pyridinium complex which undergoes aminolysis to yield the sulfamide. 1 However, in many instances the pyridine may be replaced by an equivalent, quantity of the primary... 

Piperideines unsubstituted at the nitrogen atom may be prepared from the corresponding pyridine compounds by partial reduction with sodium and boiling alcohols (the Ladenburg reduction), by electrolytic reduction, or, preferably, by reduction with aluminum hydride. l-Alkyl-3-piperideines are prepared by reduction of quaternary pyridinium salts with formic acid (the Lukes reduction) or with complex hydrides. 

Work has been performed in which the quaternary pyridinium functionality was attached to 7-oxanorbornene-5,6-exo-dicarboximide-functionalised monomers which were subsequently polymerised using a Grubbs catalyst (Grubbs catalysts are a series of transition metal carbene complexes used as catalysts for olefin metathesis). The polymer series, a-f, and quaternised polymer, a , (Figure 9.1 and Table 9.1) was designed to study the effect of the hydrophobic alkyl substituent on the antibacterial and haemolytic activities of polymers using dimethylformamide (DMF) as the solvent. 

Diphosphopyridine nucleotide and analogous quaternary pyridinium salts form complexes with bisulphite and with thiols 2-5, xhe orientation of these additions is usually uncertain and may vary with the reaction solvent used " 4, The dithionite addition products formed by quaternary pyridinium salts have attracted interest because of their connection with the dithionite reduction of diphosphopyridine nucleotide (p. 259). Thus, the formation of a 1,4-dihydropyridine (122) by reduction of (120) has been represented 6 as proceeding through a 1,2-addition product (121). Regardless of the correctness or otherwise of structure (121), the relevance of the intermediate for diphosphopyridine nucleotide reduction by dithionite has been questioned, and the yellow intermediate formed in this reaction has been formulated 8 as a charge-transfer complex between the pyridinium nucleus and 820 (see p. 261). 

Avigad and Milner224 used a turbidimetric method based on the measurement of residual turbidity caused by complexing the acid polysaccharide with such quaternary ammonium detergents as cetyl-pyridinium bromide. The activity unit was expressed as the amount of enzyme bringing about a decrease of absorbance at 400 nm of 0.01/min. 

Pyridinium and quaternary ammonium resins react with chromium trioxide, producing polymer-supported complex chromates that oxidize alcohols, and provide a very facile work-up.427... 

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