Migration salts, quaternary

It is also important to prevent the reaction of dye developers with one another. An unoxidized dye developer migrating through overlying layers of the negative could reduce and release an oxidized, immobilized dye developer, thus effecting an exchange. Reaction with quaternary salts included in the reagent aids in the immobilization of the oxidized species (66). 

Tertiary amines from quaternary ammonium salts by migration of an alkyl group... 

More recently certain quaternary ammonium salt polymers have been claimed to be effective in substantially reducing fine particle migration even in the absence of water-swelling clays (1). However, there is little information readily available concerning... 

The effectiveness of nonionic polymers as migrating clay stabilizers and the geometry of the adsorbed polymer - mineral complex may be substantially different for the nonionic polymers and the quaternary ammonium salt polymers. The observation that some quaternary ammonium salt polymers, while effective swelling clay stabilizers, are ineffective mineral fines stabilizers is consistent with a different adsorbed polymer - particle complex geometry on different mineral surfaces. 

STEVENS REARRANGEMENT. Migration of an alkyl group from a quaternary ammonium salt to an adjacent carbanionic center on treatment with strong base. The product is a rearranged tertiary amine, sulfonium, or sulfide. 

Fluoride ion-assisted desilylation has been extensively used to create an ylid from a /V-silyl methyl-quaternary ammonium salt. Its evolution to final produces) is variable and Sommelet-Hauser and Stevens rearrangement products were obtained (often as major products) in a ratio that can be shifted from one structure to another very close one, as in examples 1 and 2 dealing with //-benzyl salts.246,366 Differences in the solvents used are not significant because in the first example, HMPA does not reverse the ratio, yields and selectivity being just a bit lower, /so-toluene was proposed as an intermediate in example 1 it might also be the intermediate in example 2. Thus product partition reflects the relative ability of the C-H or the C-C bonds to be cleaved to produce aromatization with proton or a-amine carbocation migration. 

Either formulation CCLXV or CCLXVI for methiodide A requires that the iodine catalyzed rearrangement involves migration of methyl from oxygen (in CCLXI) to nitrogen. This takes one back to earlier controversies associated with the structure of pseudostrychnine quaternary salts. More work is required. 

McComsey, D. F., Maryanoff, B. E. 3-Aza-Cope Rearrangement of Quaternary N-Allyl Enammonium Salts. Stereospecific 1,3 Allyl Migration from Nitrogen to Carbon on a Tricyclic Template. J. Org. Chem. 2000, 65,4938-4943. 

Giumanini, A. G., Trombini, C., Lercker, G., Lepley, A. R. Heterobenzyl quaternary ammonium salts. IV. 2-Thenyl group as terminus and migrating moiety in the Stevens and Sommelet rearrangements of a quaternary ammonium ion. J. Org. Chem. 1976,41, 2187-2193. 

Thomson, T., Stevens, T. S. Degradation of quaternary ammonium salts. VII. New cases of radical migration. J. Chem. Soc., Abstracts 1932, 1932-1940. 

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