Resin portion

The divide-couple-recombine (DCR) method,9 also known as split-resin synthesis,8 involves the coupling of reactants to individual aliquots of resin followed by thorough mixing of the resin portions. The resin is then... 

The recovery of wood resin by naphtha extraction of the resinous portions of dead trees of the resin-bearing varieties or stumps, for example, is also used in the wood industry. The chipped wood is steamed to distill out the resinous products recoverable in this way and then extracted with a naphtha solvent, usually a well-refined, low-sulfur, paraffinic product boiling from, say, 95 to 150°C (200 to 300°F). 

Split synthesis enables the rapid generation of large numbers of related compounds (a library ) on a solid support. The procedure entails three steps that can be repeated many times. First, the resin is divided into equal portions (step 1). Each resin portion is then subjected separately to different reactions (step 2). The modified resin portions are combined and mixed (step 3) and are ready for the next cycle of the synthesis (Figure B.ll.l). Successive cycles of distributing, reacting, and mixing of the beads lead to a combinatorial increase of the diversity of products - for example four cycles with 15 different reactions per cycle lead to 154 = 50625 different com-... 

As an example, the encoding of a hypothetical 8000-member three-step library, made by three sets of 20 monomers, is depicted in Figure 9.14. This example would require the preparation of 400 different coding constructs to be hooked with the first linker to the resin, then a second orthogonal linker would be added to start the library synthesis, as shown in Figure 9.13. The 400 coded resin portions would be divided into 20 subsets of 20 portions, and each subset... 

Room temperature curing epoxy adhesives are two-component adhesives, indicating that the curing agent portion and the epoxy resin portion are packaged separately. These are often referred to as 2K adhesives, with the K derived from the German spelling of komponent. 

Recently Gordeev et al. reported (140, 141) the synthesis and iterative deconvolution of a 300-member focused library of 1,4-dihydropyridines L5 as potential calcium channel blockers inspired by the strucmre of nifedipine and other known bioactive compounds. The library was built on SP as 30 pools of 10 individuals, following the synthetic scheme shown in Fig. 7.18. Rink amine resin was deprotected, split into 10 portions (steps a and b), and treated with P-ketoesters (step c. Mi, 10 representatives A-J, Fig. 7.19) to give 10 discrete N-supported P-enaminoesters 7.30. The resin aliquots were then mixed (step d) and split again into 30 identical, 10-member pools (step e). Each resin portion was treated with a different combination of 1,3-dicarbonyls (M2, three representatives K-M, Fig. 7.19) and aldehydes (M3, 10 representatives N-W, Fig. 7.19) to give 30 pools of 10 open-chain precursors 7.31 (step f), which were cyclatively cleaved to give the final hbrary L3 (step g. Fig. 7.18). Library QC was performed by off-bead MS, identifying all the expected molecular ions in several pools. 

Moore s Extract of Bktck Cohosh. Moisten black Ciihosh root (black snake-root, or cimicifuga racemosa) in No. 50 powder, with 05 per cent, alcohol, and pat k closely in a displacer add gradually more of the alcohol until the resinous portion is exhausted evaporate tho alcoholic portion to dryness, powder tho product and pass it through a fine sieve. Proceed to displace... 

All of the product should now be out of the liquid and on the resin. This should again be checked using the blacklight. The resin portions are now combined, and soaked in 300 ml of 10% NH40H in water... 

In many adhesives formulations, the resin portion is the same or similar and what determines its properties is the hardener or catalyst that is used to cure the resin. Thus, depending on the hardener, epoxy adhesives may be referred to as amine-cured, anhydride-cured, polyamide-cured, or novolac-cured. Polyurethanes may be polyol-cured or hydroxypolyester-cured. 

The hardener portion (Part B) may also be mixed with fillers, diluents, solvents, and other additives. Fillers may be mixed in the resin portion alone or partly in the resin and partly in the hardener portion. Adhesion promoters such as Dow Corning A-180 silane may also be added to enhance the adhesion of the filler particles to the resin or hardener. Examples include several electrically conductive epoxy formulations that were used to evaluate their electrical stability on non-noble metal surfaces. The base epoxy resin was the diglycidylether of bisphenol-F (DGEBF, equivalent wt. = 170 g). Methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, and 4-methylphthalic anhydride were evaluated as curing agents with 4-methylimidazole as a catalyst. The manufacturing procedure was ... 

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