Styrene-divinylbenzene copolymer chloromethylation

To illustrate the specific operations involved, the scheme below shows the first steps and the final detachment reaction of a peptide synthesis starting from the carboxyl terminal. N-Boc-glycine is attached to chloromethylated styrene-divinylbenzene copolymer resin. This polymer swells in organic solvents but is completely insoluble. ) Treatment with HCl in acetic acid removes the fert-butoxycarbonyl (Boc) group as isobutene and carbon dioxide. The resulting amine hydrochloride is neutralized with triethylamine in DMF. 

Initial solid phase synthesis25 was carried out on Merrifield s resin (1 % crosslinked chloromethylated styrene/divinylbenzene copolymer, 200-400 mesh) because of its track record in solid-phase peptide synthesis.26 Unfortunately, the Merrifield resin has limitations as a carbohydrate carrier to study interactions between the carbohydrates and relevant binding proteins. The hydrophobic nature of the resin leads to nonspecific, irreversible protein adsorption.27 Later work utilized Rapp s TentaGel, an amphiphilic, polyethylene glycol resin.28... 

Plastic film membranes can also contain fixed ion-exchange groups. Jyo and coworkers [79] chloromethylated Amberlite XAD-2 (cross-linked styrene-divinylbenzene copolymer of the macroreticular type) and formed quaternary ammonium groups in the product by treatment with dimethyltetradecylamine. They converted the substance into the chloride, nitrate or perchlorate form and saturated it with nitrobenzene. The presence of hydrophobic ion-exchange sites... 

Polymeric supports can also be used with advantage to form monofunctional moieties from difunctional (Hies. Leznoff has used this principal in the synthesis of sex attractants on polymer supports (67). Starting from a sheap symmetrical diol he blocked one hydroxyl group by the polymer. Functionalization of cross-linked polymers is mostly performed by chloromethylation (65). A very promising method to introduce functional groups into crosslinked styrene-divinylbenzene copolymers is the direct lithiation with butyllithium in presence of N,N,N, N -tetramethyl-ethylenediamine (TMEDA) (69, 70). Metalation of linear polystyrene with butyl-lithium/TMEDA showed no exchange of benzylic hydrogen and a ratio of attack at m/p-position of 2 1 (71). In the model reaction of cumene with amylsodium, a kinetic control of the reaction path is established. After 3h of treatment with amyl-sodiuni, cumene is metalated 42% in a-, 39% m-, and 19% p-position. After 20h the mixture equilibrates to affort 100% of the thermodynamically more stable a-prod-uct (72). 

Anchoring polymers are prepared from chloromethylated styrene-divinylbenzene copolymers of either 1 equiv Cl/g or 4 equiv Cl/g capacity. These resins arc stirred for 24 h in refluxing CHC13, with either 1,4-diazabicyclo[2.2.2]octane, hexamethylenetetramine, or TMEDA. The polymers are filtered off, washed with ClIClj, acetone and Et20, then dried overnight under vacuum at 25 °C. Nitrogen elemental analysis and chloride ion titration gives a value of 80-90% quaternarization. 

Subsequently D Alello developed the polystyrene-hased resin in 1944 (4). Two years later, polystyrene anion-exchange resins made hy chloromethylation and amination of the matrix were produced. Four principal classes of ion-exchange resins were commercially availahle by the 1950s. These are the strong-acid, strong-hase, and weak-hase resins derived from styrene-divinylbenzene copolymers, and the weak-acid resins derived from cross-linked acrylics. To this day, the most widely used ion exchangers are synthetic organic polymer resins based on styrene- or acrylic-acid-type monomers as described by D Alelio in U.S. Patent 2,3666,007. 

From Metallated Phosphines.— The polymeric ligand (4) has been formed from chloromethylated styrene-divinylbenzene copolymer and lithium diphenylphosphide. Trimethylsilylation of potassium phenyl-phosphide gave the phosphine (5), which on treatment with bromine gave phenylphosphorus. (Trimethylstannyl)phosphine (6) has been prepared in high yield from trimethyltin chloride and lithium tetraphosphinoaluminate. ... 

Traditionally, anion-exchange resins have been made by a two-stage set of reactions (although other synthesis methods are now being used). The first step is a Friedel-Crafts reaction to attach the chloromethyl group to the benzene rings of styrene-divinylbenzene copolymer. Then the anion exchanger is formed by reaction of the chloromethylated resin with an amine. The most common type of... 

In order to prepare the strong- or weak-base anion-exchange resins, the styrene-divinylbenzene copolymers are reacted with chloromethyl methyl ether, which converts the phenyl residues into benzyl chloride groups that are subsequently allowed to react with either secondary or tertiary amines. The chloromethyl groups supposedly become attached to the 4-position in the phenyl residues. Trimethylamine (Dowex-1, Amberlite IRA 400) and di-methylethanolamine (Dowex-2, Amberlite 410) are typical of the tertiary amines used in the preparation of commercial resins. The quaternary ammonium ion-exchange resins are highly ionized and can be used over the entire pYl range (14). 

Ford and Yacoub [54] characterised ST-DVB and styrene-chloromethyl styrene-divinylbenzene copolymers by high resolution C-NMR. These copolymers were differentiated by the line widths of the backbone methane and chloromethyl carbon peaks [54]. Dependence of the line widths and detected peak areas on divinylbenzene content and isomeric distribution of the chloromethyl groups has been discussed [55]. 

Nagakawa and co-workers [47] applied Py-GC to a structural study of various chloromethyl substituted PS copolymers prepared by different methods and they applied (TGA) gravimetric analysis to the dehydrochlorination and thermal degradation behaviour of these copolymers. Typical pyrograms of ST-DVB, styrene-chloromethylstyrene-divinylbenzene (ST-Cl-MST-DVB and chlorinated p-methyl styrene divinylbenzene copolymers are shown in Figures 1.5-1.7. 

Poly(vinylbenzyl mercaptan) has been described by several authors. The synthesis always follows the same path chloromethylation of polystyrene followed by reaction with thiourea and hydrolysis of the isothiuronium salt 1,53,55,63-65). The redox properties of a polymer obtained from chloromethylated styrene-divinylbenzene copolymers have been evaluated (3). Redox capacities givrai for mercaptyl resins were determined to be 2. W>-5.27 milliequivalents of iodine reduced per gram of (dry) resin in aqueous potassium iodide. The oxidized form of the resin could be easily reduced with 10% aqueous bisulfite fmr a complete redox cycle. Recently polyvinylbenzyl mercaptan resins were prepared directly by treating chloromethylat polystyrene with KSH in dimethyl formamide (66). 

Galeazzi, L. (1976) Process for the chloromethylation of styrene-divinylbenzene copolymers. U.S. Patent No. 3,997,706, Washington, DC U.S. Patent and Trademark Office. 

The first, and still widely used, polymer-supported ester is formed from an amino acid and a chloromethylated copolymer of styrene-divinylbenzene. Originally it was cleaved by basic hydrolysis (2 N NaOH, FtOH, 25°, 1 h). Subsequently, it has been cleaved by hydrogenolysis (H2/Pd-C, DMF, 40°, 60 psi, 24 h, 71% yield), and by HF, which concurrently removes many amine protective groups. Monoesterification of a symmetrical dicarboxylic acid chloride can be effected by reaction with a hydroxymethyl copolymer of styrene-divinylbenzene to give an ester a mono salt of a diacid was converted into a dibenzyl polymer. ... 

Cholestyramine Cholestyramine (20.1.2) is a copolymer of divinylbenzene and styrene, which undergoes chloromethylation and afterwards is reacted with triethylamine [5]. 

Strong Base Anion Exchangers. As in the synthesis of weak base anion exchangers, strong base resins are manufactured from styrenic as well as acrylic copolymers. Those based on copolymers of styrene and divinylbenzene are chloromethylated and then aminated. These reactions are the same as for the styrenic weakbase resins. The essential difference is the amine used for amination. Trimethylamine [75-50-3], N(CH3)3, and A/,A/-dimethylethanolamine [108-01-0], (CH3)2NCH2CH2OH, are most commonly used. Both form quaternary ammonium functional groups similar to (8). 

PCD is a copolymer of styrene and divinylbenzene where all the styrene groups are chloromethylated. When the content of divinylbenzene was 2 mol%, the chloromethyl groups were found to remain almost intact during suspension polym-... 

The most commonly used polymeric support is a copolymer styrene/divinylbenzene functionalized with various reactive groups such as chloromethyl (Merrifield resin) and various spacers such as ethylene glycol (Wang-type resin). The supports now available vary one from another in many aspects and properties functionalization, cross-linking, porosity, loading, bead size. All these variations generate different swelling behaviours, different hydrophilicity, and different chemical stability. 

Chemicals Metal-free 5,10,15,20-tetrakis-(4-pyridyl)porphyrin and metal-ffee 5,10,15,20-tetrakis-(4-aminophenyl)-porphyrin (Porphyrin Produets, fax 001-801-753-6731, e-mail porphyrin eaehenet.com Porphyrin Systems, fax 0049-451-502-1130, e-mail contaet porphyrin-systems.de) linear poly(ehloro-methylstyrene) containing 6.56 mmol Cl per g polymer with m = 50,000 mol g as a 3 2 mixture of 3- and 4-isomers (Aldrieh) eross-linked chloromethylated styrene/divinylbenzene (2%) copolymer containing 1 mmol Cl per g polymer (Aldrich). 

Poly (divinylbenzene-co-ethylstyrene). See Divinylbenzene-ethylstyrene copolymer Poly (divinylbenzene-co-trimethyl (vinylbenzyl) ammonium chloride). See Chloromethylated aminated styrene-divinylbenzene resin PolyDMDAAC PolyDMDAC. See... 

Styrene/DVB resin, chloromethylated aminated. See Chloromethylated aminated styrene-divinylbenzene resin Styrene epoxide. See Styrene oxide Styrene-ethylene/butylene-styrene block copolymer CAS 66070-58-4... 

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