Quaternization review

Quaternary ammonium compounds biocidal activity mechanism, 1, 401 toxicity, 1, 124 Quaternization heterocyclic compounds reviews, 1, 73 ( )-Quebrach amine synthesis, 1, 490 Queen substance synthesis, 1, 439 4, 777 Quercetin occurrence, 3, 878 pentamethyl ether photolysis, 3, 696 photooxidation, 3, 695 Quercetrin hydrolysis, 3, 878 Quinacetol sulfate as fungicide, 2, 514 Quinacridone, 2,9-dimethyl-, 1, 336 Quinacridone pigments, 1, 335-336 Quinacrine... 

The third volume of this series covers three specific groups of compounds the carbolines (reviewed by R. A. Abramovitch and I. D. Spenser), the thiatriazoles (K. A. Jensen and C. Pedersen), and the pentazoles (I. Ugi). The remaining four chapters deal with topics of general chemical interest from the heterocyclic viewpoint the quaternization of heterocyclics (G. F. Duffin), carbene reactions (C. W. Rees and C. E. Smithen), applications of the Hammett equation (H. H. Jaffe and H. Lloyd Jones), and some aspects of the nucleophilic substitution of heterocyclic azines (G. Rluminati). 

Some reviews characterize the former two types 1 and 2 as quaternized... 

There has been much interest in diquaternary salts of 4,4 -bipyridine, the electrochemistry of which has recently been reviewed. l.l -Dialkyl diquaternary salts of 4,4 -bipyridines are prepared by treating 4,4 -bipyri-dines with excess of an alkyl halide or a dialkyl sulfate or other alkylating agent. This method has been used extensively and provides diquaternary salts of type 92 where both alkyl quaternizing groups are the same (i.e., 92 R = 211,467,689,962,967,968 Qf particular interest is the diquater-... 

For a review of ammonia as a synthetic reagent, see Jeyaraman, in Pizey, Ref. 593, vol. 5, 1983, pp. 9-83. For a review of stereoselectivity in this reaction, especially where the tertiary nitrogen is included in a ring, see Bottini. Sei. Org. Transform. 1970, 7, 89-142, For a review of quaternization of heieroaromatic rings, sec Zoltewicz Deady Adv. Heteroevci. Chem. 1978, 22. 71-121,... 

Our review focuses on important developments dealing with quaternization of annular nitrogen atoms of heterocyclic compounds. Only six-and five-membered heteroaromatic rings are included. The organization comprises two main parts. Part I is a comprehensive narrative describing the main electronic and steric factors of heteroaromatic... 

Four chapters in the present volume bring older reviews up to date. Those on the quinoxalines (Cheeseman and Werstiuk) and on hetero-aromatic quaternization (Zoltewicz and Deady) carry forward contributions on the same subjects in Volumes 2 (1963) and 3 (1964), respectively, of this Series, while those on the phenanthrolines (L. A. Summers) and the isatogens and indolones (Hiremath and Hooper) deal with topics previously covered elsewhere. The cyclazines, a relatively new field of chemistry, are reviewed by Flitsch and Kramer, and the azapentalenes— the wide variety of nitrogen-containing heterocycles formed by the fusion of two aromatic five-membered rings—are collected into one chapter by Elguero, Claramunt, and A. J. H. Summers. 

Emphasis is placed on simply substituted free bases. The problems of conformational equilibria in /V-alkylpiperidinium salts and N-quaternization reactions and the relationships of these to conformational equilibria in the free bases are not covered, since this area is a large one requiring separate treatment. In other relevant previous reviews, the topics include heterocyclic conformational analysis,3-7 interactions in azacyclic systems,8 the conformational analysis of piperidine,9 hexahydropyrimidines,10,11 hexahydropyri-dazines,12 quinolizidines,13 the conformational analysis of bi- and polycyclic... 

Naphthyridine chemistry has been well reviewed by Allen1 (up to 1947), and by Weiss and Hauser2 (up to 1958). It has also been considered incidentally by Duffin8 (quaternization reactions) and by Campbell4 in The Chemistry of Carbon Compounds. ... 

Quaternization of imdazoles with alkyl halides to form imidazolium ions was reviewed in detail in CHEC-II(1996). During the past decade, a great deal of chemistry has been reported on the formation of imidazolium ions, with the majority focusing on the utility of imidazolium ions. There are two major areas of chemistry that were, in large part. 

Preparation- The role of 02p- and N2p- through space hyper-valent interactions involving a developing phosphonium centre in quaternization reactions has been reviewed, together with their role in other aspects of phosphonium salt chemistry. 

Historically, phospholanium salts have been prepared by quaternization in high yield of a selected phospholane with an alkyl halide. Although numerous methods exist for the preparation of the desired phospholanes (recently reviewed ), most of these have major drawbacks, including (1) very critical conditions, such as reaction time, dilution effects, and temperature (2) expensive and/or difficult to manipulate reagents and (3) the necessity of a multistep synthetic sequence giving overall low yields of phospholane. A general example of the latter would be the reaction of a substituted dihalophosphine with a 1,3-diene and hydrolysis to the phospholene oxide, which then can be catalytically reduced to the phospholane oxide and subsequently converted to the phospholane. ... 

Aminobenzimidazoles, quaternized with l-bromoprop-2-yne and converted with ammonia into the 2-imines, cyclize on heating with a strong base the quaternary salt behaves similarly. The enzyme catalase promotes the cyclization of the amino-alkene (12.5) to a benzimidazole under comparatively mild conditions (review [B-53]). 

Quaternized pyridines which have an R R CH group on the nitrogen are useful compounds because of the ease with which they react with bases to give reactive ylides the latter add on to some alkynes such as DMAD under mild conditions. The quaternized pyridines form ylides more readily when R is an electron-attracting group such as acyl, 4-nitrophenyl, tosyl, nitrile or carboxylic ester. When both R and R are electrophilic, as in (NQ2CH, ylide formation is very facile [2280, 2284, 2419, 2422, 2970]. The chemistry of iV-substituted pyridines [1870] and the use of azomethine ylides [2509] have been reviewed. 

Special ionic liquids. A review of chiral ionic liquids is available/ A series of Lewis basic ionic liquids are prepared from DABCO by quaternization with RCl followed by anion exchange (to BF4, PFg)/... 

The quaternization of (benzo)pyridazines by alkyl halides (these systems are not readily susceptible to arylation) was reviewed in CHEC-I <84CHEC-l(3B)l>. Monoquaternization of pyridazines occurs more readily than other diazines but less readily than pyridine, reflecting the intermediate basicity/nucleophilicity of pyridazine. Diquaternization of pyridazine can only be achieved with oxonium salts, particularly Me30 BF4 . As with protonation and A-oxidation, mixtures of products are often obtained on quaternization of unsymmetrical pyridazines and have been the subject of theoretical studies. A number of 2-(ribofuranosyl)-3(2//)-pyridazinones have been prepared by stannic chloride catalyzed alkylation of 3-(trimethylsilyloxy)pyridazines with protected 1-0-ace-tylribofuranose <83JHC369>. The quaternization behavior of phthalazines is similar to that of pyridazines, but with cinnolines alkylation usually occurs at N-2, unless there is a particularly bulky substituent at C-3. 

The fact that the monomethylene derivative above only forms a monoquaternary salt may be contrasted with the fact that the diphosphine (PhaP)2CH2 forms a diquaternary salt and that the phosphino-phosphazene, Ph2P(=NC6H4X)-CHaPPha (X = H, p-Br, p-Me, m-Me, p-OMe, or m,p-NOa), is preferentially quaternized at the tervalent phosphorus atom. The basicities and quaternization behaviour of these compounds were examined and it was shown that the diphosphazenes [PhaP(=NC6-H4X)]aCH2 are diacid bases, whereas the diphosphines such as (PhaP)2CH2 are monoacid bases. Some of these features are also discussed in an extensive review of the base properties of monophosphazenes, both from chemical and physical standpoints. 

The H, C, N, N, and F NMR spectral data has been thoroughly reviewed <83AHC(34)80> for systems (28)-(30) and only more studies since 1983 will be presented here. The C shifts for (28) and some monodeuterated derivatives have been reported <840MR(22)192>. Proton NMR studies have also determined the sites of quaternization of (28). Using DIFNOE NMR, irradiation of the quaternary a-proton signal or that at C-3 confirmed that protonation occurred at N-2 <89X7041, 90JCR(S)9>. 

DADMAC 13C, for example, can be readily polymerized imder these cyclopolymerization conditions to yield PolyDADMAC in which a structure composed of 5-membered A -heterocycles predominates. 13C will readily polymerize at 35°C employing ammonium persulfate as the initiator. 13C is readily copolymerized with other diallyl monomers, with acrylamide monomers such as 28C or diacetone acrylamide, or quaternized 1C. Extensive reviews of cyclopol5mieriza-tion and cyclocopolymerization can be found in Reference 188. Recent examples of cyclocopolymerization with sulfobetaine (14C) and carboxybetaine (15C) diallyl ammonium monomers are given in References (188-191). 

In fact, the first systematic micellization studies of copolymers containing cationic hydrophilic blocks were those of Selb and Gallot, who have also given a review of this topic [190]. The typical polyelectrolyte copolymers investigated by these authors were polystyrene-b-poly(quaternized 4-vinylpyridine) PS-PQV4P with the following structure ... 

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