Chloromethyl sulfone anion

As carriers for ion exchangers they find application in HPLC. Cation exchangers are prepared by sulfonation, anion exchangers are prepared by nitration. Reduction to amines and alkylation, are achieved through quarternation and chloromethylation, respectively. 

Reactions of salicylic aldehydes with the chloromethyl tolyl sulfone anion afford 2-hydroxydihydrobenzofurans in moderate to good yields (Scheme 98) <1998T6811>. Formation of an epoxide intermediate that rearranges to the corresponding homologated alcohol is believed to be involved. Decarboxylation of the reaction product is prevented by lactol formation <1998T6811>. 

Also, the observed highly regioselective course in the SnFI substitutions in 2-R-3-nitro-l, 8-naphthyridines (R = FI, OFI, Cl, NFI2, OEt) with the anion of chloromethyl phenyl sulfone was explained by MNDO quantum-chemical calculations showing that, like in the aminations, the interaction of FIOMO of the nucleophile with LUMO of the nitronaphthyridines controls the regioselectivity (91JFIC1075). 

At the same time, the reaction of 1,2,4-triazine 4-oxides 55 with the anion of chloromethyl phenyl sulfone affords 5-(l-chloro-l-phenylmethyl)-l,2,4-triazines 66. In this case, autoaromatization of the a -adducts proceeds by the deoxygenative... 

E. Reduction of Halomethyl Phenyl Sulfones and Chloromethyl Phenyl Sulfoxide by Fluorenide Anions... 

Aromatic electrophilic substitution is used commercially to produce styrene polymers with ion-exchange properties by the incorporation of sulfonic acid or quaternary ammonium groups [Brydson, 1999 Lucas et al., 1980 Miller et al., 1963]. Crosslinked styrene-divinyl-benzene copolymers are used as the starting polymer to obtain insoluble final products, usually in the form of beads and also membranes. The use of polystyrene itself would yield soluble ion-exchange products. An anion-exchange product is obtained by chloromethylation followed by reaction with a tertiary amine (Eq. 9-38) while sulfonation yields a cation-exchange product (Eq. 9-39) ... 

We are interested in the application of polymers as adsorbents, ion exchangers, fuel cells, and permeable materials. In this regard, the first resins with some of these properties were obtained by D Aleleio in 1944 based on the copolymerization of styrene and divinylbenzene. Unfunctionalized polystyrene resins cross-linked with divinylbenzene (Amberlite) are widely applied as adsorbents [191,192], In addition, the polystyrene-divinylbenzene resins functionalized with sulfuric acid (sulfonation) to create negatively charged sulfonic sites are applied as cation exchangers, and treated by chloromethylation followed by animation produce anionic resins [193,194],... 

The resins are prepared first by copolymerizing styrene (ST) and divinylbenzene (DVB), resulting in a cross-linked polystyrene. Usually, they are produced in the form of spherical beads. These beads are sulfonated with sulfuric acid for anionic resins and methylated with chloromethyl ether followed by quatemization with trimethylamine for cationic resins. Two types of resins exist gel and microporous. The microporous beads are used to remove ionic substances quickly while the gel-type beads are used for sustaining drug release over a long period of time. 

The ion exchange resins can be obtained either from the polymerization of substituted styrene or by the chemical modification of the polymer. For example, styrene/divinylbenzene (SDVB) polymer can be modified by chloromethylation (using HCl and formaldehyde in the presence of ZnCb) followed by reaction with a tertiary amine. This derivatization leads to a strong anion exchange material. Sulfonation of SDVB leads to a strong cation exchanger. The idealized structure of SDVB and of the anion and cation exchangers obtained from this material are shown below ... 

The vast literature on applications of PTC in substitution reactions is mainly restricted to nucleophilic substitution reactions with an anionic reagent. However, recently the use of PTC in electrophilic reactions, like diazotization andazocou-pling C-and N-nitrosation, C-alkylation, acid hydrolysis of esters, chloromethylation, nitrite-initiated nitrations, and so on have been reported(Velichko et al., 1992 Kachurin et al., 1995). Alkylbenzene sulfonates and lipophilic sodium tetrakis[3,5-bis(trifluoromethyl)phenylboranate are typical electrophilic PT catalysts. Lipophilic dipolar molecules of the betaine type and zwitterionic compounds also function well as PT agents for both nucleophilic as well as electrophilic reactions. 

The two insoluble compounds precipitate and are removed from the water by filtration. Thus by the successive usage of cation and anion-exchange resins sodium chloride could be removed from water. An example of a cation-exchange resin is sulfonated styrene-divinyl-benzene polymer and an anion-exchange resin can be made by chloromethylating styrene-divinyl copolymer and replacing the chlorines with tr i me thy1ami ne. 

However, under the conditions that favor dissociation of the adducts and disfavor p-elimination, namely, a higher temperature and absence of a strong base, the conventional S Ar of fluorine atom can be observed [13]. Interestingly, the reaction of wefa-dinitrobenzene with an excess of this carbanion gave the disubstitution product, whereas with equimolar amounts of reactants only monosubstitution proceeds. It is evident that the anion of 2,4-dinitrobenzyl phenyl sulfone is still sufficiently active electrophile to react with the carbanion of chloromethyl phenyl sulfone (Scheme 3) [14]. 

Introduction of arylsulfonylmethyl substituents into nitroheteroaromatic rings is of great practical value because these sulfones are versatile intermediates in organic synthesis. Nitrobenzyl aryl sulfones and their heterocyclic analogues can easily be transformed into the corresponding ethenyl derivatives by a simple alkylation with simultaneous elimination of arylsulfinate anion [125]. Diethyl methylenemalonate substituent can be introduced in the positimi 4- of 5-nitroimidazole via the VNS reaction of 5-nitroimidazole with the carbanion of chloromethyl phenyl sulfone [112, 124], followed by condensation of the obtained 4-(phenylsulfonyl)methyl derivative with diethyl bromomalonate or diethyl ketomalonate (Scheme 33) [126]. 

The tripodal ligand sulphos was obtained from benzyltris(chloromethyl)-methane by sulfonation, and subsequent reaction with the diphenylphos-phide anion in DMSO ... 

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