Bisquaternary salts

Cleavage of the phosphorus-phosphorus link has been shown to occur in the reactions of bisquaternary salts derived from... 

The olefinic group of vinylpyridines undergoes a variety of reactions, which include reduction to the ethane, addition reactions, dimerizations, and polymerizations. There are few voltammetry studies on the isomeric vinylpyridines (26). The reduction of the bisquaternary salt of 1,2-di(2-pyridyl)-ethylene has been studied, and the role of adsorption and autoinhibition during reduction of l,2-di(4-pyridyl)ethylene was also determined.49,50... 

Phenanthrolines (84) are obtained by photochemical cyclization of 1,2-dipyridyl ethylenes (85). Their bisquaternary salts (86) are obtained by polarography of the corresponding pyridinium salts... 

If a pyridyl substituent is attached to the oxazole ring at C(2), it is alkylated in preference to the oxazole nitrogen atom 4- and 5-pyridyloxazoles yield bisquaternary salts. 

Bisquaternary salts of berberine, dihydroberberine, and other alkaloids have been prepared by quaternization with dihalides such as 2,2 -dichlorodiethylamine, sarcolysin, and cyclophosphane.105... 

B[18]-N204 (4) turned out to be a very useful compound for testing the double-quatemization reactions, since it possesses four aromatic protons which are well separated in the lH NMR. Thus, the structures of the products can be easily established by means of NMR spectroscopy. Representative example of this double-quatemi-zation method is illustrated in Scheme 10. For preparative performance, e.g. a 1 1 mixture of 4 and bis(2-iodoethyl)ether (41) (ca, 0.08 M solution in acetone) was exposed to the pressure of 10 kbar 40) for 20 h. The bisquaternary salt 42 precipitated during the reaction course quantitatively. 

Tse-Lok Ho 3I) has explored the effectivness of the following four nucleophiles in dequatemization reactions sodium azide, sodium thiosulphate, thiourea and tri-phenylphosphine. Among.which, triphenylphosphine turned out to be the most effective demethylating agent. A strong solvent dependence on dequatemization has been demonstrated, indicating dimethylformamide as a superior solvent in all cases. In this manner, (2B.2.1]cryptand (44) was obtained from bisquaternary salt 43 in 87% yield (Scheme 11). 

All quaternization reactions were performed under the same conditions, e.g., in ca. 0.08 M solution in acetone, at ambient temperature, for 20 h, and a pressure of 10 kbar was maintained during the reaction course. Without exception colourless crystalline solids precipitate in the reaction cell, and after a simple work-up (washing with hexane and drying in vaccuo) the isolated bisquaternary salts were analytically pure. Demethylation was carried out by heating the respective salt with triphenyl-phosphine in boiling DMF, followed by column chromatography on alumina. Yields obtained for the quaternization and demethylation reactions are listed in Table 2. 

The influence of solvent was studied for the reaction 4 + 41a -> 42a (Scheme 15). Six different aprotic solvents were chosen as a reaction medium. All reactions were performed under 10 kbar pressure at 30 °C. The yield of bisquaternary salt are collected in Tafale 4. 

Bisquaternary salts of laudanosine with itself and with other tetrahydroisoquinolines and long chain dihalides have been prepared as potential neuromuscular blocking agents of the same type as tubocurarine. The most widely studied of such salts is atracurium (44) (R. Hughes and D.J. Chappie, Brit.J.Anaesth., 1981, 31 J.B. Stenlake et al., Eur.J. 

Bisquaternary salts of laudanosine, and of laudanosine and simpler dihydroisoquinolines,witn long-chain dihalides have been... 

Reaction of quinoxaline with ethyl iodide in boiling acetonitrile gives ethylquinoxalinium iodide in 76% yield, and treatment of the parent base with methyl p-toluenesulfonate at room temperature gives methyl-quinoxalinium p-toluenesulfonate in quantitative yield7 There are apparently no reports of the isolation of quinoxaline bisquaternary salts. 

Bisquaternary salts (70), prepared from the enantiomers of N-methylpavine and 1,10-di-iododecane, showed equal curarimetric neuromuscular blocking activity. ... 

IcPs more readily afford bisquaternary salts as compared to IbPs. For example, l,3,5-trialkyl(dialkylphenyl)imidazolio[4,5-c]pyridinium ditosylates 255 and 256 were obtained by fusion with toluene sulphonic acid esters of 1,2-dimethyl- 86 or l-phenyl-2-methyl-IcP 612 (70KG228, 71KG693), or of a mixture of A -monomethyl IcP derivatives (72KG683). 

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