Solution-phase techniques

In the case of pharmaceutical solids that are dominated by carbon and proton nuclei, the dipole-dipole interactions may be simplified. The carbon and proton nuclei may be perceived as dilute and abundant based upon then-isotopic natural abundance, respectively (Table 1). Homonuclear 13C—13C dipolar interactions essentially do not exist because of the low concentration of 13C nuclei (natural abundance of 1.1%). On the other hand, H—13C dipolar interactions contribute significantly to the broad resonances, but this heteronuclear interaction may be removed through simple high-power proton decoupling fields, similar to solution-phase techniques. 

Several review articles have been published about SILAR-grown films.4-7 The SILAR technique, including its advantages and disanvantages and the equipment employed, is presented in Section 8.2. Materials that have been prepared by SILAR are reviewed in Section 8.3. Short descriptions of the related ILGAR, ECALE, and other sequential solution-phase techniques follow in Sections 8.4- 8.6. 

The Wellman-Lord Process is not, in itself, a conversion method, but rather a solution phase technique for concentrating a dilute SO2 effluent stream to provide a suitably rich feed for Claus redox conversion. When coupled with the Claus Process, it constitutes an overall desulphurisation system which involves all three phases gas, liquid solution, and solid crystalline. 

Alkali metal doping of Cjq is also possible by solution-phase techniques [1,118-121]. K CgQ and Rb CgQ containing small fractions of the superconducting M3C50 phases were prepared by allowing toluene solutions of Cjq to react with the alkali metal [118, 119]. During the reaction, the alkali metal fullerides form a black precipitate. In another example, sonication of a solution of Cjq and excess potassium in TMEDA yields K3C5q(THF)j4 with a defined stoichiometry [104],... 

COMBINATIONS OF SOLID- AND SOLUTION-PHASE TECHNIQUES IN ORGANIC SYNTHESIS... 

The A -unsubstituted (3-lactams are important building blocks for the synthesis of several biologically active antibiotics. However, solution phase techniques normally include acidic conditions, which are not tolerable with acid-sensitive functionalities. In an elegant approach, Banik et al. [133] developed a solid phase synthetic route to access A -unsubstituted (3-lactams directly using Rink resin as the solid support. The method for construction of (3-lactam ring was based on Staudin-ger reaction and subsequent cleavage from the solid support was done with TFA in dichloromethane (Scheme 30). 

X-Ray crystallographic analysis used alongside solution phase techniques such as NMR, is invaluable in the design of selective anion receptors as it can be used to define the solid-state structure of the anion-bound complex. Several X-ray structures of anion-bound complexes of [Ln.la]3+ have been defined recently (acetate, lactate, citrate, alanine, glycine, methionine, serine and threonine) [8,21,22], The complexes adopt a monocapped square antiprismatic structure with one base comprising of four N atoms of the macrocycle and the other base containing three O atoms of the pendent arms. The latter base is completed by a carboxylate O donor of the anion, which binds in a bidentate manner and simultaneously caps this base by O (acetate), OH (a-hydroxy acids) or NH2 (a-amino acids). The nature of the donor atom in the capping (or axial) position correlates well with the observed NMR shift in the solution phase. 

Coats reported on the parallel synthesis of delta/mu agonists, as depicted in Scheme 59. Both solid- and solution-phase techniques were evaluated with respect to the reactivity of the vinyl bromide template, but solution-phase couplings gave more rapid reactions. In the latter case it was found that the... 

This review does not intend to provide absolute answers about the utility of solution-phase techniques versus solid phase, which are, anyway, strongly influenced by the specific requirements of each project. Rather, it will show the versatility of solution-phase techniques in generating combinatorial libraries through the detailed illustration of several different approaches. A list of the methodologies which will be covered in this review is shown in Figure 7.1. 

FIGURE 7.1 Solution phase techniques for the generation of combinational libraries. 

Using classical solution-phase techniques, show how you would synthesize Ala-Val and then combine it with Ile-Leu-Phe to give Ile-Leu-Phe-Ala-Val. 

Characterization of derivatized NPs can be performed using standard solution-phase techniques such as nuclear magnetic resonance (NMR), infrared (IR), and UV-Vis spectroscopy. As will be demonstrated, derivatization of NPs with specifically tailored functional groups allows exploitation of ionic and hydrogen bonding interactions for the creation of controlled assemblies for a variety of applications. 

Fig. 4.32 Demonstration of the cumulative effects of techniques employed in C CP/MAS SSNMR spectroscopy on a sample of dideoxyinosine. (a) High-power proton decoupling combined with magic-angle spinning (MAS) and cross polarization (CP) (b) high-power proton decoupling and MAS at 5 kHz (c) high-power proton decoupling only and (d) conventional solution phase techniques. (From Bugay 1993, as modified by Byrn et al. 1999.)...

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