Support reagent

P. Pfeifer, in Preparative Chemistry Using Supported Reagents, P. Laszlo, ed.. Academic, New York, 1987. 

One widely used method of formation of protected compounds involves polymer-supported reagents, with the advantage of simple workup by filtration and automated syntheses, especially of polypeptides. Polymer-supported reagents are used to protect a terminal — COOH group as a polymer-bound ester (RCOOR —( ) during peptide syntheses, to protect primary alcohols as... 

R. J. Booth and J.C. Hodges, Solid-supported reagent strategies for rapid purification of combinatorial synthesis products, Acc Chem Res 32 18-26 1999. 

S. V. Ley, l.R. Baxendale, G. Brusotti, M. Caldarelli, A. Massi and M. Nesi, Solid-supported Reagents for Multi-step Organic Synthesis Preparation and Application, II Farmaco 57 321-330 2002. 

S. Bhattacharyya, Polymer-supported reagents and catalysts Recent advances in synthetic applications. Comb Chem High Throughput Screening 3 65-92 2000. 

Organic dyes which are not complexed or are salts of metals are included in Chapter 4 (use the CAS Registry Numbers to find them). Commercially available polymer supported reagents are indicated with under the appropriate reagent. 

Tetra-n-propylammonium perruthenate (TPAP, tetrapropyl tetraoxoruthenate) [114615-82-6] M 351.4, m 160"(dec). It is a strong oxidant and may explode on heating. It can be washed with aq n-propanol, then H2O and dried over KOH in a vac. It is stable at room temp but best stored in a refrigerator. It is sol in CH2CI2 and MeCN. [Dengel et al. Transition Met Chem 10 98 1985 Griffith et al. J Chem Soc, Chem Commun 1625 1987.] Polymer supported reagent is available commercially. 

Polymer supported reagents, catalysts, protecting groups, and mediators can be used in place of the corresponding small molecule materials (Sherrington, 1991 Sundell and Nasman, 1993). The reactive species is tightly bound to a macromolecular support which immobilizes it. This generally makes toxic, noxious, or corrosive materials much safer. The use of polystyrene sulfonic acid catalyst for the manufacture of methyl r-butyl... 

Gupta et al. reported that the Vilsmeier-Haack cyclisation of acetanilides 20 using supported reagents and microwave-irradiation in solvent-free conditions is rapid and efficient. Reaction yields are good, although only a few activated derivatives have been investigated. 

It years, there has been a considerable growth of interest in the catalysis of organic IS by inorganic reagents supported on high surface areas, Envirocat, a new family of supported reagents, which exhibits both Bronstead and Lev/is acid character, are ideal for environmentally friendly chemistry. These reagents are non-toxic powders that can be easily... 

Viewed in conjunction with the solid-like, nonvolatile nature of ionic liquids, it is apparent that TSILs can be thought of as liquid versions of solid-supported reagents. Unlike solid-supported reagents, however, TSILs possess the added advantages of kinetic mobility of the grafted functionality and an enormous operational surface area (Figure 2.3-1). It is this combination of features that makes TSILs an aspect of ionic liquids chemistry that is poised for explosive growth. 

Figure 2.3-1 Substrate interactions with (I to r) solid-supported reagent, polymer gel support-...

Amos prepared his polymer-supported reagent in two steps from commercially available polystyrene beads (bromination, then condensation with lithium diphenylphosphide). He found that a useful range of sulphoxides could be reduced effectively, in good yields and in a few hours, to give clean samples of sulphides. 

Two polymer-supported reagents have been developed for the oxidation of sulphoxides to sulphones these involve peracid groups150, and bound hypervalent metals activated by t-butyl hydroperoxide151,152. 

Polychloromethylsulphonylbiphenyls, mass spectra of 154, 155 Polyenes, synthesis of 771 Polymerization, of sulphoxides 846 Polymer-supported reagents 928 Polymorphonuclear leukocytes 854 Poly(olefin sulphonejs, radiolysis of 916-922 Polysulphones, radiolysis of 913 Population analysis 14, 15, 21, 22 Propargylic sulphenates, rearrangement of 736-739... 

A solid-phase Diels-Alder reaction that uses polymer-supported reagents has recently attracted considerable attention and its use is expanding rapidly. 

Fig. 29 Microwave-promoted multicomponent synthesis of polysubstituted thiophenes on soluble PEG support. Reagents and conditions a NCCH2OOH, DCC, DMAP, CHCI3, MW 130 W, 5 min b RCOCH2R, S8, diisopropylethylamine, MW 130 W, 15 min c R"COCl, di-isopropylethylamine, 0 °C to rt, 3 h d 1% KCN in CH3OH, o.n. R = H or alkyl R = alkyl or acyl R" = CH3, Ph...

Fig. 34 Preparation of a 4-thiazolidinone library using an ionic liquid support. Reagents and conditions a MW 100 °C, l-2h, open vessel b R"NH2, t-BuOK, MW 100-150°C, 10-20 min. R = H, Me, CH2COOH R = Pr, i-Pr, i-Bu, Bn, piperonyl, CH2CH(OMe)2, CH2CH CH2 R" = Pr, Bu, Bn, or cyclic derivatives as piperonyl, piperidine, pyrrolidine,...

Fig. 35 Preparation of 2-thioxo tetrahydropyrimidin-4-(2H)-ones on ionic hquid support. Reagents and conditions a R N = C = S, MeCN, rt, 18 h b Et2NH, MW, 120 °C, 15-45 min. R = Pr, i-PrCH2, PhCH2 R = Me, Bu...

Fig. 36 Synthesis of a polysubstituted pyran on ionic liquid support. Reagents and conditions a ethyl acetoacetate, MW 200 W, reflux, 10 min b arylidenemalononitriles, pyridine, MeCN, MW 200 W, reflux, 15-20 min c NaOMe, MeOH, rt, 6h...

Synthesis of Heterocycles Using Polymer-Supported Reagents under Microwave Irradiation... 

Synthesis of Heteroq cles Using Polymer-Supported Reagents... 

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