Solubility analogs

In this particular system, 4-nitrobenzaldehyde dimethyl acetal is deprotected by the acid catalyst, followed by the addition of methyl vinyl ketone (MVK) in an amine-catalyzed Baylis-Hillman reaction to give the product (Scheme 5.14). A yield of 65% for the final product was observed when the catalysts described in Scheme 5.13 were used, compared with no observed yield for the reaction with their soluble analogs. 

SMPT, succinimidyloxycarbonyl-a-methyl-a-(2-pyridyldithio)toluene, contains an NHS ester end and a pyridyl disulfide end similar to SPDP, but its hindered disulfide makes conjugates formed with this reagent more stable (Thorpe et al., 1987) (Chapter 5, Section 1.2). The reagent is especially useful in forming immunotoxin conjugates for in vivo administration (Chapter 21, Section 2.1). A water-soluble analog of this crosslinker containing an extended spacer arm is also commercially available as sulfo-LC-SMPT (Thermo Fisher). 

A water-soluble analog to SMPB, called sulfo-SMPB [sulfosuccinimidyl-4-(p-maleimidophenyl) butyrate] contains a negatively charged sulfonate group which lends considerable hydrophilic-ity to the molecule (Thermo Fisher). Sulfo-SMPB may be added directly to aqueous reaction... 

A water-soluble analog of NHS-biotin containing a negatively charged sulfonate group on its NHS ring structure also is available. Sulfo-NHS-biotin may be added directly to aqueous reactions without the need for organic solvent dissolution. A concentrated stock solution may be prepared in water to facilitate the addition of a small quantity to a reaction, but hydrolysis of the NHS ester will occur at a rapid rate, so the solution must be used immediately. 

Salgo and Pryor [111] studied the effect of Trolox C (a water-soluble analog of vitamin E) on peroxynitrite-mediated DNA damage in rat thymocytes. They proposed that peroxynitrite mediated the formation of TBAR products, which caused the DNA-protein crosslinks. The latter were inhibited by the posttreatment of cells with Trolox. However, Trolox produced no effects on hydrogen peroxide- or bleomycin-induced DNA damage in human lymphocytes [108],... 

The above considerations led to the expectation that it might be possible to construct soluble analogs of 5 in which an appropriate ligand mimicked the environment imparted by the polystyrene matrix in the immediate vicinity of the metal. The results of these experiments are reported in the final section. 

Other analogs of CA-4, 7 have been developed and are also in clinical trials. These include AVE8062 (formerly known as AC-7700,10), a water soluble analog [33]. 

Polar, water-soluble analogs of these molecules (23 and 24) have also been studied and have been shown to form helical columns in a variety of polar solvents such as methanol, butanol, acetonitrile, and water, by virtue of solvophobic interactions between the large aromatic cores.82,83 A stepwise association process is observed when alcohol solutions of 24 are cooled. The... 

Nagata, T., Pohl, M., Weiner, H., and Finke, R.G., Polyoxoanion-supported organometallic complexes carbonyls of Rhenium(I), Iridium(I), and Rhodium(I) that are soluble analogs of solid-oxide-supported M(CO) + and that exhibit novel M(CO)n+ mobility, Inorg. Chem., 36, 1366, 1997. 

Chemical differences, such as prolonged activity or altered selectivity of a catalyst in supported form compared with its soluble analog. 

Furthermore, polymer-assisted solution-phase syntheses also show several advantages over Merrifield-type syntheses. Fxcept for some industrially employed heterogeneous catalysts the requirement of high loading capacities for the sohd supports is not necessarily of prime importance for immobilized catalysts. Because not every site needs to react, lower loadings are acceptable. The recovered catalyst is often available for immediate reuse. A discussion on immobilized catalysts should also include a brief listing of obstacles associated with their use, particular in comparison to their soluble analogs ... 

Lipid soluble analogs of thiamine (vitamin Bj) 1126 have a number of therapeutic uses, and examples are acetiamine 1127 (R = Me), bentiamine 1127 (R = Ph), fursultiamine 1128, and octotiamine 1129 which has antiinflammatory activity. 

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