Quaternary nitrogen compounds

The large activating effect of a methyl group upon the reactivity of aromatic quaternary nitrogen compounds noted above has been confirmed by Utley and Vaughan55, who have measured the second-order rate coefficients and the... 

Cationic surfactants produce a positively charged surfactant ion in solution and are mainly quaternary nitrogen compounds such as amines and derivatives and quaternary ammonium salts. Owing to their poor cleaning properties, they are little used as detergents rather their use is a result of their bacteriocidal qualities. Relatively little is known about the mechanisms of biodegradation of these compounds. 

Cholinesterase inhibitors have minimal effects by direct action on vascular smooth muscle because most vascular beds lack cholinergic innervation (coronary vasculature is an exception). At moderate doses, cholinesterase inhibitors cause an increase in systemic vascular resistance and blood pressure that is initiated at sympathetic ganglia in the case of quaternary nitrogen compounds and also at central sympathetic centers in the case of lipid-soluble agents. Atropine, acting in the central and peripheral nervous systems, can prevent the increase of blood pressure and the increased plasma norepinephrine. 

A solution of potassium iodide and bismuth subnitrate in acetic acid, used for tiie detection of all loids and quaternary nitrogen compounds. 

Atropine is the prototype drug of this group and will be described first. Other named agents will be mentioned only in so far as they differ from atropine. All act as non-selective and competitive antagonists of the various muscarinic receptor subtypes (Ml-3). Atropine is a simple tertiary amine certain others (see Summary) are quaternary nitrogen compounds, a modification that is important as it intensifies antimuscarinic potency in the gut, imparts ganglionblocking effects and reduces CNS penetration. 

The analysis of quaternary nitrogen compounds by HPLC requires chromatographic systems, such as ion-pair and reversed-phase chromatography, which are able to separate highly polar compounds. Reviews on ion-pair HPLC have been given . Both straight-phase (adsorption and/or partition) and reversed-phase ion-pair chromatography have been used. 

The retina which ontogenetically is regarded as a part of the brain, and hence presumably should be encompassed by the BBB, seems to be somewhat more accessible to quaternary nitrogen compounds than is the brain elsewhere (Andersen et al., 1970). 

By means of the technique used by Aarseth and Barstad (1968), the present authors have studied the permeability of the rat BBB and BRB to 4 quaternary nitrogen compounds, viz. an irreversible AChE inhibitor (2-MPAM-ES) (Fig. 4A see also Barstad et al., 1969) and 3 AChE reactivators (Fig. 4B-D). 

To see whether active transport of the quaternary nitrogen compounds outwards through the BBB or BRB could play any role in these events, similar experiments were performed on two groups of animals pretreated with inhibitors of metabolism-dependent transport, viz., 2,4-dinitrophenol and ouabain. In some additional ex-... 

Four quaternary nitrogen compounds, one of them an irreversible cholinesterase inhibitor (2-MPAM-ES), the remaining 3 cholinesterase reactivators (P2S, Tx 10 and Toxogonin), were used in a study of the permeability of the blood-brain barrier (BBB) and the blood-retinal barrier (BRB), the latter being, from an ontogenetic point of view, a part of the former. 

Andersen, R. A., Barstad, J. A. B. and Laake, K. (1970) Permeability of the blood-retina barrier to quaternary nitrogen compounds. Acta Pharmacol. Toxicol., Suppl. 1, 28, 31. 

With the aid of ion-pairing agents (e.g., alkylsulfonic acids), alkaloids, including quaternary nitrogen compounds, can be extracted from an acidic aqueous solution with organic solvents. It should be noted that common anions as CP, Br , 1 and acetate also result in ion pairs readily soluble in organic solvents. In liquid/liquid extractions this may result in poor... 

Le Bel s resolution of a quaternary ammonium compound l abcdX. was doubtful, but Pope, S. J. Peachey, and A. W. Harvey resolved a quaternary nitrogen compound by means of camphorsulphonic acid. S. Smiles and Pope and Peachey prepared optically active sulphur compounds. Pope and Neville a selenium compound, and Pope and Peachey tin compounds. A very simple compound, CHCl SOgH), was resolved by Pope and Read. Pope and C. S. Gibson prepared alkyl derivatives of gold, and Pope and Peachey of platinum. 

Horner et al. have studied the mechanisms by which onium compounds inhibit steel corrosion. Kichigin et al. studied tetra-n-butylammonium cation (TBA ) and other quaternary nitrogen compounds in the presence of iodide, and Aramaki et al. studied TBA+ in the presence of halides, SOj", SCN , SH , NOJ, and N3. In all these cases, halides were shown to be necessary for good inhibitor performance and the observed behavior was consistent with competitive co-adsorption of ion pairs (side by side). Sulfonium derivatives also require the presence of halide ions and, likewise, apparently co-adsorb to form ion pairs on the surface. As discussed below, unsaturated oxygen compounds, such as aldehydes and acetylenic alcohols, also require a halide ion for good performance. 

The method covers cationic surface-active substances of the type of quaternary nitrogen compounds, such as (R4N) and the like, having molecular weights from about 250 to 600. 

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