Hydroxylated resins

A thioglycoside was immobilized by the following sequence of reactions. Treatment of the dibutyltin acetal of diol 36 with succinic anhydride afforded 37 in an excellent yield of 85%. Attachment of Fmoc protected glycine to TentaGel hydroxyl resin (38, 0.37 mmol/g resin) under standard conditions followed by removal of the Fmoc group by treatment with piperidine gave polymer 27. Compound 37 was immobilized by amide bond formation with 27 in the presence of... 

The commercially available 3-amino-1,2,4-dithiazole-5-one, (3), has been attached to a hydroxyl resin via a succinic acid linker, and has been used as an efficient sulfur-transfer reagent for the solution-phase synthesis of phos-phorothioates. DNA synthesis scale-up to lOOg of a 20-mer phosphorothioate has been examined " key to this was the purification of the product, which was carried out using a high efficiency polymeric anion exchange chromatographic media. 

Simple hydroxylic resins were obtained from chloromethylated resins (1), commercially available (gel-type resins) or prepared by chloromethylation of styrene units according to the method described by Itsuno (in particular for macroreticular polymers) [5]. Chloromethyl groups were reacted with acetic acid and EtsN to give polymeric esters 2 which were hydrolyzed with KOH-H20-methylglycol [6]. Quantitative transformation of chloromethyl into hydroxymethyl groups was observed in all cases. 

Hydroxyl resins have been converted to chloroformates or active carbonates to provide solid supports that can be used for reversible anchoring of amines as carbamates. Thus, nitrophenylcarbonate 2a (Table 2) has been used to anchor symmetrical diamines and, after further reactions, treatment with TFA released products as trifluoroacetamides [104]. A chloroformate derivative of Tentagel-S 2b has been used to anchor the amino group of a-amino acids and the products used to synthesize dipeptides that could be cleaved by TFA [105]. Succinimidylcarbonate resins 2c have been prepared by treatment of... 

As discussed in Section IV, photolysis is a mild cleavage method that is attractive for combinatorial drug discovery because products can be released into neutral aqueous solution suitable for direct screening. Amine analogues of the hydroxyl resins described earlier have been reported. Thus, (aminomethyl)-6>-nitrobenzyl supports 7n have been reported on which short peptide amides could be synthesized with cleavage occurring upon irradiation at 350 nm in the presence of ammonia [323]. 2-Nitrobenzhydryl (NBHA) supports 7o have also been used for peptide amide assembly using Boc-protected amino acids. The anchor was unaffected by 4 N HCl-dioxane... 

Acid chlorides can be coupled in the presence of a 1 1 mixture of an amine [175] and HOBt or the potassium salts of HOBt [177]. In both cases, the corresponding OBt ester is formed initially. Fmoc-amino acid chlorides have been successfully applied in solid-phase syntheses [175], as well as for the incorporation of the first amino acid on hindered hydroxyl resins [178,179]. 

Direct anchoring of Mnp-gIle-(, S)-mLeu-OH (28) to hydroxyl resin was reported by Verdini and coworkers [134] during the synthesis of the C-terminal PMRI analogue of neurotensin [glle, (R,5)-mLeu ]NT(8-13)... 

Instead of Box ligand, carboxamidate coordinate with rhodium have been tested successfully for the r clopropanation of some fimctionalized alkenes [99] (Scheme 50).The carboxamidate anchored to the NovaSyn Tentagel hydroxyl resin (TG) or Merrifield resin (Scheme 50) was treated with chiral dithodium tetrakis[methyl 2-oxypyrrolidine-5(iS)-carboxylate] (Rh2((S, S)MEPY)4) leading to the corresponding Rh-106 and Rh-107 precatalyst. 

Ion-exchange resins. The constituent phenolic hydroxyl groups in the insoluble phenol-formaldehyde resins react with cations of salts ... 

The use of hydroxyethyl (also hydroxypropyl) methacrylate as a monomer permits the introduction of reactive hydroxyl groups into the copolymers. This offers the possibility for subsequent cross-linking with an HO-reactive difunctional agent (diisocyanate, diepoxide, or melamine-formaldehyde resin). Hydroxyl groups promote adhesion to polar substrates. 

Uses. The largest uses of butanediol are internal consumption in manufacture of tetrahydrofuran and butyrolactone (145). The largest merchant uses are for poly(butylene terephthalate) resins (see Polyesters,thermoplastic) and in polyurethanes, both as a chain extender and as an ingredient in a hydroxyl-terminated polyester used as a macroglycol. Butanediol is also used as a solvent, as a monomer for vadous condensation polymers, and as an intermediate in the manufacture of other chemicals. 

Esters. Most acryhc acid is used in the form of its methyl, ethyl, and butyl esters. Specialty monomeric esters with a hydroxyl, amino, or other functional group are used to provide adhesion, latent cross-linking capabihty, or different solubihty characteristics. The principal routes to esters are direct esterification with alcohols in the presence of a strong acid catalyst such as sulfuric acid, a soluble sulfonic acid, or sulfonic acid resins addition to alkylene oxides to give hydroxyalkyl acryhc esters and addition to the double bond of olefins in the presence of strong acid catalyst (19,20) to give ethyl or secondary alkyl acrylates. 

Eyrol 51 is a water-soluble Hquid containing about 21% phosphoms. It is made by a multistep process from dimethyl methylphosphonate, phosphoms pentoxide, and ethylene oxide. The end groups are principally primary hydroxyl and the compound can thus be incorporated chemically into aminoplasts, phenoHc resins, and polyurethanes. Eyrol 51, or 58 if diluted with a small amount of isopropanol, is used along with amino resins to produce a flame-retardant resin finish on paper used for automotive air filters, or for backcoating of upholstery fabric to pass the British or California flammabiHty standards. 

The synthesis of 2,4-dihydroxyacetophenone [89-84-9] (21) by acylation reactions of resorcinol has been extensively studied. The reaction is performed using acetic anhydride (104), acetyl chloride (105), or acetic acid (106). The esterification of resorcinol by acetic anhydride followed by the isomerization of the diacetate intermediate has also been described in the presence of zinc chloride (107). Alkylation of resorcinol can be carried out using ethers (108), olefins (109), or alcohols (110). The catalysts which are generally used include sulfuric acid, phosphoric and polyphosphoric acids, acidic resins, or aluminum and iron derivatives. 2-Chlororesorcinol [6201-65-1] (22) is obtained by a sulfonation—chloration—desulfonation technique (111). 1,2,4-Trihydroxybenzene [533-73-3] (23) is obtained by hydroxylation of resorcinol using hydrogen peroxide (112) or peracids (113). 

Weak base resins when in the free base (hydroxyl) form are not capable of splitting neutral salts such as sodium chloride. Salt forms of weak base resins release anions to the Hquid phase if other ions for which the resin has a greater selectivity are present. 

Oxidation of LLDPE starts at temperatures above 150°C. This reaction produces hydroxyl and carboxyl groups in polymer molecules as well as low molecular weight compounds such as water, aldehydes, ketones, and alcohols. Oxidation reactions can occur during LLDPE pelletization and processing to protect molten resins from oxygen attack during these operations, antioxidants (radical inhibitors) must be used. These antioxidants (qv) are added to LLDPE resins in concentrations of 0.1—0.5 wt %, and maybe naphthyl amines or phenylenediamines, substituted phenols, quinones, and alkyl phosphites (4), although inhibitors based on hindered phenols are preferred. 

Gas chromatography (gc) has been used extensively to analyze phenoHc resins for unreacted phenol monomer as weU as certain two- and three-ring constituents in both novolak and resole resins (61). It is also used in monitoring the production processes of the monomers, eg, when phenol is alkylated with isobutylene to produce butylphenol. Usually, the phenoHc hydroxyl must be derivatized before analysis to provide a more volatile compound. The gc analysis of complex systems, such as resoles, provides distinct resolution of over 20 one- and two-ring compounds having various degrees of methylolation. In some cases, hemiformals may be detected if they have been properly capped (53). 

Fig. 2. Functional end groups and solution viscosity during polyester resin manufacture. Acid value is defined as the milligrams of KOH required to neutralize 1 g of polymer hydroxyl value is defined as the milligrams of acid equivalent required to neutralize 1 g of polymer. Solution viscosities are...

As Eigure 1 implies, there is usually some residual acidity as well as free hydroxyl groups left in the resin molecules. Stmcture-property relationships and the principles commonly followed to design the resin stmcture are discussed later. 

---