RAM support

Substituted tetrahydroquinoxalin-2-ones have been prepared on the RAM support 7c [303] by first coupling 4-fluoro-3-nitrobenzoic acid to the support in the presence of HATU using a procedure comparable to that described earlier followed by displacement of fluorine by an a-aminoester. Reduction of the nitro group useing tin (II) chloride lead to ring closure (Scheme 13) and further alkylation was followed by TFA-induced cleavage. 

Gas chromatography-mass spectrometry. A Finnigan 3300 gas chromatograph-mass spectrometer system operated on line with a Finnigan 6000 data system was used for all analyses. Thirty m x 0.3 ram support-coated open tubular (SCOT) gas chromatographic glass columns with OV-1 as the liquid phase were used for these studies. 

Plate-and-Frame Filter Presses. In the conventional plate-and-frame press (Fig. 14), a sequence of perforated square, or rectangular, plates alternating with hoUow frames is mounted on suitable supports and pressed together with hydrauHc or screw-driven rams. The plates are covered with a filter cloth which also forms the sealing gasket. The slurry is pumped iato the frames and the filtrate is drained from the plates. 

Windows 3.x, 95, or NT, 40 MB hard drive, 16 MB RAM. Cost Depends on type perpetual license, fixed period license, non-commercial academic are available. For example, one-year lease including upgrades, training, and technical support is 11,500. 

The microwave acceleration of Ugi condensations on a sohd support have been utilized in the synthesis of an 18-membered targeted hbrary of a-acylamino amides [60], Irradiation of the four components, immobilizing the amine on TentaGel S RAM, for 3-5 min in a single-mode microwave synthesizer gave the products in moderate to excellent yields and high purity (Scheme 7). 

The first example of microwave-promoted solid-phase methodology in heterocyclic chemistry was the arylation of thiophene and indole via Suzuki couplings on TentaGel S RAM resin, as demonstrated by Hallberg and coworkers in 1996, before temperature- and pressure-controlled microwave instruments were even available [189]. Three years later Schotten and coworkers presented analogous but aqueous Suzuki couplings of 5-bromo-thiophene anchored to PEG soluble support via a carboxylic function at its C-2 position [116]. Unfortunately, this work was performed in a do-... 

Support for this conclusion is provided by the hydroperoxide specificity of BP oxidation. The scheme presented in Figure 6 requires that the same oxidizing agent is generated by reaction of h2°2/ peroxy acids, or alkyl hydroperoxides with the peroxidase. Oxidation of any compound by the iron-oxo intermediates should be supported by any hydroperoxide that is reduced by the peroxidase. This is clearly not the case for oxidation of BP by ram seminal vesicle microsomes as the data in Figure 7 illustrate. Quinone formation is supported by fatty acid hydroperoxides but very poorly or not at all by simple alkyl hydroperoxides or H2C>2. The fact that... 

The first solid-phase application of the Ugi four-component condensation, generating an 18-member acylamino amide library, was presented in 1999 by Nielsen and Hoel [53]. The authors described a library generation utilizing amino-functionalized PEG-polystyrene (Tentagel S RAM) as the solid support (Scheme 7.36). A set of three aldehydes, three carboxylic acids, and two isonitriles was used for the generation of the 18-member library. 

The same authors performed a microwave assisted Stille reaction on the Rink amide (RAM) Tentagel polymer-tethered 4-iodobenzoic acid [5 b]. Successful palladium-catalyzed coupling of heteroaryl boronic acid with anchored 4-iodobenzoic acid enabled both >99% conversion of the starting material within 3.8 min (45 W) and a minimal decomposition of the solid support. The coupling reactions were realized in a mixture of polar solvents (H20-EtOH-DME, 2.5 1.5 6). 

Equation 11.28 Stille coupling utilizing a RAM-linker on a polymer support. 

Scheme 2.2 Graphical representations of the inner and outer phases of the chiro-RAM-TE support. G = grafting group (monoureido-monoisocyanate intermediate), obtained as previously described [61] (i) LiCl/dry DMSO, 80°C, 3 h. (ii) dry pyridine, 70°C, 12 h.

An example of LC-MS separation of four racemic 3-blockers achieved on a TE CSPis reported in Figure 2.16. The chromatographic assay developed was applied in the direct HPLC injection of human plasma containing sotalol on a chiro-RAM-TE support [64] (Figure 2.17). 

The assistance of Ram Thapa with the calculations and of Annabelle Wiseman with preparation of the manuscript is gratefully acknowledged. This work was supported by the Natural Sciences and Engineering Research Council of Canada and the University of Alberta. 

Multi-component reactions where three or more components build a single product have received considerable interest for several years. Since most of these reactions tolerate a wide range of building block combinations, these types of reactions are frequently applied for combinatorial purposes. A solid-phase application towards the Ugi four component condensation (Ugi-4CC) generating a 18-member acylamino amide library appeared in 199939. The acylamino amide library was synthesised using amino-functionalised PEG-polystyrene (TentaGel S RAM) as the solid support. (Scheme 7.22). 

---