Chloromethylated styrene-divinylbenzene

Chloromethylation of styrene-divinylbenzene-mixing polymerizate and following reaction with trimethylamine. 

On stirring at room temperature ozonides of terminal alkenes (prepared in dichloromethane at — 70 °C) with a polymer-supported tertiary amine obtained from chloromethylated poly(styrene/divinylbenzene) and piperidine, followed by filtration and concentration under reduced pressure, the products (aldehydes or ketones) can be obtained easily in almost pure form in high yields <2003T493>. However, yields are low for cycloalkenes because apparently they form monomeric and polymeric ozonides. 

A logical way of increasing the fraction of transition metal atoms used for active centre formation seems to be the application of the metal compound to a polymer surface [189], The carrier could be identical with, or similar to, the product. This approach is being intensively studied, and various polymers are being tested as carriers, for example poly(styrene-co-divinylbenzene) [190], chloromethylated poly(styrene-co-divinylbenzene) [191], poly-ethylene-0ra/t-poly(4-vinylpyridine) [192], and many others. 

Kobayashi et al. reported the first synthesis of polymer-supported silyl enolates (thioketene silyl acetals) and their reactions with aldehydes for the preparation of 1,3-diol, / -hydroxy carboxylic acid, and /i-hydroxy aldehyde libraries (Scheme 10.37) [104]. In the presence of 20 mol% Sc(OTf)3, polymer-supported silyl enolate 42 derived from chloromethyl copoly(styrene-l% divinylbenzene) resin via 41 reacts smoothly with a variety of aldehydes. The resulting adducts can be easily purified by acid treatment and subsequent washing with water and organic solvents. The purified adducts are converted into 1,3-diols with LiBH4, -hydroxy carboxylic acids with NaOH, and -hydroxy aldehydes with DIBALH. This strategy has been used for efficient synfhesis of diverse monosaccharide derivatives [105]. 

Polymeric benzaldehyde. Frechet and Pelle have prepared a polymeric form of benzaldehyde by chloromethylation of a divinylbenzene—styrene copolymer followed by oxidation of the chloromethylated product with DMSO. The reagent was used to protect the 4- and 6-hydroxyl group of methyl a-D-glucopyranoside (1) by formation of the acetal (2), which can then be converted... 

These are chloromethylated poly(styrene-co-divinylbenzene) beads. 

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... 

Potassium alum dodecahydrate clarifier, sugar beet processing Polyacrylic acid clarifier, sugarcane processing Polyacrylic acid clarifier, sugar processing Chloromethylated aminated styrene-divinylbenzene resin clarifier, vinegar... 

Chloromethylated aminated styrene-divinylbenzene resin 60207-90-1 Busan 1292 Busan 1298 Propiconazole 60209-82-7 Bernel Ester 105 Dermol 105... 

Infrared spectra are valuable in the examination of small molecular-weight intermediates, such as blocked and activated derivatives of amino acids. The stretching frequency for the urethane carbonyl (around 1700 cm" ) is distinguishable from that of the activated carbonyl group in anhydrides (over 1800 cm or in active esters (around 1800 cm ). Also, changes in ir spectra were used for monitoring transformations in polymeric supports. For instance, conversion of chloromethylated copoly-styrene-divinylbenzene to the acetoxy... 

Usual attachment of the first amino acid unit to the chloromethylated poly-styrene-divinylbenzene resin has been improved, for example, with Boc-Asn, by-condensing the amino acid (2.0 mmoles) in DMF with triethylamine (1.8 mmoles) during one day at room temperature. Cleavage of the peptide end product from the polymer as the amide derivative has been accomplished using ammonia in DMF in a sealed reaction vessel at room temperature for 5 days. A careful stud - of several peptide bond-forming reagents and polymer supports in respect to racemization has revealed the DCCI procedure to be far inferior to DCCI-NHS or EEDQ. With the model tripeptide Gly-Ala-Leu (racemization assessment by means of the Izumiya procedure), the product was found to... 

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. 

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. 

FIGURE 27 14 A section of polystyrene showing one of the benzene rings modified by chloromethylation Indi vidual polystyrene chains in the resin used in solid phase peptide synthesis are con nected to one another at various points (cross linked) by adding a small amount of p divinylbenzene to the styrene monomer The chloromethylation step is carried out under conditions such that only about 10% of the benzene rings bear —CH2CI groups... 

Polypeptide Synthesis and Analysis. Sihca or controUed-pore glass supports treated with (chloromethyl)phenylethyltrimethoxysilane [68128-25-6] or its derivatives are replacing chloromethylated styrene—divinylbenzene (Merrifield resin) as supports in polypeptide synthesis. The sdylated support reacts with the triethyl ammonium salt of a protected amino acid. Once the initial amino acid residue has been coupled to the support, a variety of peptide synthesis methods can be used (34). At the completion of synthesis, the anchored peptide is separated from the support with hydrogen bromide in acetic acid (see Protein engineering Proteins). 

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. ... 

The starting material for the synthesis of this chelating resin is chloromethylated styrene-divinylbenzene, which undergoes an amination reaction and is then treated with monochloracetic acid ... 

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... 

Three main types of polymer-based monoliths are polymethacrylate-based monoliths where methacrylate forms the major component of the monomers for polymerization, polyacrylamide-based monoliths where cross-linked polyacrylamide is synthesized directly within the capillary, and polystyrene-based monoliths that are usually prepared from styrene and 4-(chloromethyl) styrene as monomers and divinylbenzene (DVB) as the cross-linker. 

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... 

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

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