Resin activity

Chemical Chemical Air and/or Activated Resin Ion Ultrafiltra-tion Flo atation / ph... 

Ratings are for a mildly activated resin (Type RMA) flux. 

Newer types employ surface active resins. 

Visible light activated resin compositions containing calcium hydroxide have been made available as cavity lining materials (99) for pulp capping and pulpotomy, and may offer in other appHcations an alternative to the calcium sahcylate type cements. 

Material used to activate resins to promote hardening. For polyesters, organic peroxides are used primarily. For epoxies, amines and anhydrides are used. 

The extent to which (i.e. degree of conversion, Xmax) the active resin must have reacted at the paint surface to be polished by the moving sea water (influence of insoluble paint components (e.g. Ti02), sailing speed, paint porosity, etc.). 

Anti-estrogenic effect. Ethanol (95%) extract of the dried aerial parts, administered intragastric to rats at variable doses was inactive . Petroleum ether extract of the dried leaf, administered intraperitoneally to female rats at a dose equivalent to 10 mg/kg tetrahydrocannabinol (THC) on 11-21 days of age, was active . Antifertility effect. Petroleum ether extract of the entire plant, administered by gastric intubation to female mice at doses of 75 mg/kg and 150 mg/kg, was active. A dose of 3 mg/kg, produced weak activity ". Resin, administered by gastric intubation to male mice at variable dosage levels, was inactive . ... 

Teratogenic activity. Resin, administered orally to pregnant rabbits at a dose of 1 mL/ kg, was active k Alcohol extract of the dried leaves, administered intragastrically to pregnant rats at a dose of 125 mg/kg from days 7 to 16 of gestation, was active. The fetuses showed several gross abnormalities, visceral anomalies, and skeletal mal-formations . Water extract of the dried... 

Eluent 2 is a lower ionic strength buffer and is used only to resolve DMA from interfering As (ill). With this eluent, MMA, p-APA, and As(V) have very long retention times and will accumulate on the column typing up active resin sites. Therefore the column must be flushed with Eluent 1 after 10-15 samples have been analyzed and the column reequilibrated for 1 hour with Eluent 2 before further analysis. The analysis of DMA and As (ill) can be performed at the rate of 10 samples per hour, and each chromatogram requires 3 minutes. 

Many types of chiral stationary phase are available. Pirkle columns contain a silica support with bonded aminopropyl groups used to bind a derivative of D-phenyl-glycine. These phases are relatively unstable and the selectivity coefficient is close to one. More recently, chiral separations have been performed on optically active resins or cyclodextrins (oligosaccharides) bonded to silica gel through a small hydrocarbon chain linker (Fig. 3.11). These cyclodextrins possess an internal cavity that is hydro-phobic while the external part is hydrophilic. These molecules allow the selective inclusion of a great variety of compounds that can form diastereoisomers at the surface of the chiral phase leading to reversible complexes. 

The Development and Application of Tetrafluorophenol-Activated Resins for Rapid Amine Derivatization... 

Selected Examples of Known Linkers for Generating Activated Resins for Amine... 

The reaction of TFP resin with sulfonyl chlorides (3 equiv.) in the presence of diisopropylamine (DIEA 3 equiv.) provides the corresponding sulfonate-activated resins (Fig. 2). Alternatively, sulfonic acids may be loaded directly onto TFP using DIC (via the intermediate sulfonic acid anhydride) as the coupling reagent. Analogous to the carboxylate esters, the sulfonate ester resins are stable when dry and may be kept at room temperature for an extended period of time without decomposition. This is one of the clear advantages of the polymeric TFP reagents versus acid chlorides the latter decompose once exposed to air and moisture. 

Both the quality of TFP resin and the resulting polymeric-activated resins may be quantitatively determined by 19F NMR spectroscopy.1 This nondestructive technique takes advantage of the high sensitivity, natural abundance (the 1/2 spin nucleus 19F is 100% abundant), and large chemical shift dispersion ( 200 ppm) of the 19F nucleus. The 19F NMR spectrum of TFP resin shows two resonances at 148 and 165 ppm (Fig. 3), each corresponding to 2 equiv. fluorine nuclei. The 19F NMR spectrum of TFP-activated carboxylate and sulfonate resins shows two resonances at ca. 

The reaction of a TFP reagent with an amine is performed by first suspending a 20% excess of activated resin (loading established) in DMF. A limiting amount of amine, 0.8 equiv. based on the resin loading, is added to the resin as a dilute solution in a solvent such as DMF.24 The reaction... 

It is convenient to produce ca. 10 fj,M of product per well by dispensing ca. 12-15 mg of TFP-activated resin per well, assuming a loading of ca. 0.95 mmol/g and an 80-90% reaction yield. This quantity of product is sufficient for evaluation in multiple biological assays. 

Procedure. A TFP-activated resin was placed in a small reaction vessel to which was added a DMF solution of 2-methylbenzylamine. The reaction mixture was gently agitated for 12 h and filtered. The filtrate was evaporated to dryness and the residue dissolved in CDC13 or other deuterated solvent. The sample was analyzed by NMR. Loading was determined by integration and comparison of the aromatic methyl protons and the Q-methylene protons of the product amide relative to the starting amine. 

Procedure. A 3-ml polypropylene reaction vial was charged with a TFP-activated resin, either the carboxylate or sulfonate ester type, and 1 ml of DMF. The reaction mixture was gentle agitated for 10 min and an amine (0.065 mmol) was added. The reaction mixture was further agitated for 16 h and filtered. The resin was washed with DCM (3x2 ml) and the filtrate and washings were combined. The solvent was removed in vacuo and the amide or sulfonamide (>85% yield) so obtained was analyzed by LC/MS for purity and identity. 

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