Resins chloromethylated

In the case of the benzyloxytrityl-hydroxylamineresin 24b, the starting material is the Merrifield resin, chloromethylated polystyrene (1.7 mmol Cl x g 1) which is treated with 3 equiv. of 4-hydroxy-methyl benzoate in DMA with sodium methylate as base. The Beilstein test is used for monitoring and microanalyses showed the absence of chloride (Scheme 6). 

Uses Intermediate in anionic-exchange quaternary resins chloromethylating agent. 

Smith and Liu have successfully prepared an unsymmetrical analog of a Katsui-type salen ligand possessing a hydroxyalkyl group in the 6-position, which facilitated the formation of an ester Hnkage to a polystyrene carboxyl chloride resin (Figure 5.19) derived from Merrifield s resin (chloromethylated polystyrene,... 

Materials. Crosslinked polystyrene beads were purchased from Bio-Rad Laboratories and were dried under vacuo at 40 C. Merrifield resin (chloromethyl group content 0.9 meq/g) was purchased from Pierce Chemical Co. A series of 3-nitro-4-acyloxy-benzoic acids ( ) were prepared by methods described in the literature. The long-chain p-nitrophenyl ester substrates were purchased from Sigma Chemical Co. p-Nitrophenyl acetate was a product of Pierce Chemical Co. and sublimed in vacuo before being used. Polystyrene (average MW 22,000) was purchased from Aldrich Chemical Co. 

Deprotection-protection Aminomethyl resin Chloromethyl resin Wang resin 2-Chlorotrityl resin Benzoic acid resin HMPB-MBHA resin TentaGel... 

Hydroxyethylene resin HMPA resin Chloromethyl resin Hydroxymethyl resin Tritylchloride resin Rink amide resin Wang resin REM resin Aminomethyl resin Chloromethyl resin Wang resin Rink amide resin PAL amide resin MBHA resin Chloromethyl resin Chlorotrityl resin Wang resin PAM resin Polystyrene resin Chloromethyl resin Chlorotrityl resin Wang resin Rink amide resin Sasrin resin Polystyrene resin Chloromethyl resin Benzoic acid resin Wang resin Trityl resin 2-Chlorotrityl resin PAL resin Rink amide resin MBHA resin REM resin Hydroxymethyl resin Polystyrene Aminomethyl resin Chloromethyl resin 2-Chlorotrityl resin Hydroxyethyl resin Rink amide resin Wang resin MBHA resin Sieber resin... 

Cleavage, nonstandard Aminomethyl resin Chloromethyl resin Benzoic acid resin Hydroxymethyl resin Rink amide resin Wang resin PAL amide resin MBHA resin Kaiser oxime resin REM resin TentaGel S OH TentaGel S PHB Spheron Ara 1000 ... 

Synonyms Poly (divinylbenzene-co-trimethyl (vinylbenzyl) ammonium chloride) Styrene/DVB resin, chloromethylated aminated Hazardous Decomp. Prods. Heated to decomp., emits toxic fumes of Cr and NO2 Uses Decolorizing agent and clarifier for sugar processing... 

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... 

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... 

The typical acid catalysts used for novolak resins are sulfuric acid, sulfonic acid, oxaUc acid, or occasionally phosphoric acid. Hydrochloric acid, although once widely used, has been abandoned because of the possible formation of toxic chloromethyl ether by-products. The type of acid catalyst used and reaction conditions affect resin stmcture and properties. For example, oxaUc acid, used for resins chosen for electrical appHcations, decomposes into volatile by-products at elevated processing temperatures. OxaUc acid-cataly2ed novolaks contain small amounts (1—2% of the original formaldehyde) of ben2odioxanes formed by the cycli2ation and dehydration of the ben2yl alcohol hemiformal intermediates. 

Platinum-group metals (qv) form complexes with chelating polymers with various 8-mercaptoquinoline [491-33-8] derivatives (83) (see Chelating agents). Hydroxy-substituted quinolines have been incorporated in phenol—formaldehyde resins (84). Stannic chloride catalyzes the condensation of bis(chloromethyl)benzene with quinoline (85). 

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 epoxidation is generally conducted in two steps (/) the polyol is added to epichlorohydrin in the presence of a Lewis acid catalyst (stannic chloride, boron triduoride) to produce the chlorohydrin intermediate, and (2) the intermediate is dehydrohalogenated with sodium hydroxide to yield the aliphatic glycidyl ether. A prominent side-reaction is the conversion of aliphatic hydroxyl groups (formed by the initial reaction) into chloromethyl groups by epichlorohydrin. The aliphatic glycidyl ether resins are used as flexibilizers for aromatic resins and as reactive diluents to reduce viscosities in resin systems. 

A typical system is a chlorome thy late d polystyrene resin cross-linked with 2 or 4% p-divinylbenzene and different amounts of chloromethylated sites (0.7—3.7 mequiv. of Cl per g of polymer) . The reaction is shown schematically in Eq. (6.19) and additional information may be found in Sects. 8.3 and 8.8. 

The above methods occurred in 3 steps, therefore, these methods are not preferred. For instance, in the first step, o-, m-, and p-bromostyrene and its copolymer are synthesized. In the second step, Li-PS is synthesized from the reaction of copolymers with an organic compound containing LI. The abovementioned reactions are made with different compounds of Li-PS in the third step. These methods were also investigated by Ayres and Mann [34], who used the synthesis of PS containing chloro groups with chloromethylated PS as the first step. In the second step, formil resin was obtained by oxidation of chlorometylated PS. In the third step, carboxyl-ated PS was obtained by the oxidation of formol resin with acetic acid at 20°C for 48 h. There are some disad-... 

A polymer-bound analog of the p-sulfonato-calix[6]arenes is described in a Shinkai patent [31,32], which states that the hexakis(carbetoxymethyl)ether of p-sulfonatocalix[6]arene was partially nitrated, ami-nated, and fixed on crosslinked chloromethylated polystyrene. This resin is stated to absorb 108 ixg of uranium... 

The chloromethylated polystyrene resin used for Merrifteld solid-phase peptide synthesis is prepared by treatment of polystyrene with chloromethyl methyl ether and a Lewis acid catalyst. Propose a mechanism for the reaction. 

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 ... 

The checkers used beads of chloromethylated polymer available from Bio. Rad. Laboratories, Richmond, California (Bio Beads S-X2). Chlorine analysis (Note 3) showed that the resin contained 1.06 milli-equivalents of chlorine per gram, as specified by the manufacturer. 

The acidic catalysts used for these reactions include formic acid, HX (X = F, Cl, Br), oxalic acid, phosphoric acid, sulfuric acid, sulfamic acid, and p-toluenesulfonic acid.4 Oxalic acid is preferred since resins with low color can be obtained. Oxalic acid also decomposes at high temperatures (>180°C) to C02, CO, and water, which facilitates the removal of this catalyst thermally. Typically, 1-6 wt % catalyst is used. Hydrochloric acid results in corrosive materials and reportedly releases carcinogenic chloromethyl ether by-products during resin synthesis.2... 

A useful application in the manufacture of ion-exchange resins may well be possible which avoids the use of carcinogenic chloromethyl ether. Here, a polymer of p-methyl styrene is chlorinated on the side chain with aqueous NaOCl and a phase-transfer catalyst. Sasson et al. (1986) have shown how stubborn . substituted aromatics like nitro/chlorotoluenes can be oxidized to the corresponding acids by using aqueous NaOCl containing Ru based catalyst. 

Even in solution the relative rigidity of the polymer support can play a significant role in the reactivity of attached functional groups. Contrasting studies conducted with chloromethylated derivatives of poly(arylene ether sulfone) (Tg 175°C), phenoxy resin (Tg= 65°C) and polystyrene (Tg= 105°C) allow evaluation of chain rigidity effects. We have shown that the rates of quaternization of chloromethylated poly(arylene ether sulfones) and phenoxy resin deviate from the anticipated second order process at... 

---