Combinatorial synthesis Compound libraries

Combinatorial synthesis towards libraries of compound mixtures can be done either on a solid support or in solution. In both cases an effective decoding strategy is required to extract structural information from the results of the biological assay (see Section 1.4.2.1.2 Deconvolution by Orthogonal Libraries). 

The benzodiazepine nucleus is now recognized as an important pharmacophore and a solid-phase synthesis of benzodiazepines which will allow the combinatorial synthesis of libraries of benzodiazepine-based compounds for pharmacological testing has been described <92JA10997>. 

HTS data as well as virtual screening can guide and direct the design of combinatorial libraries. A genetic algorithm (GA) can be applied to the generation of combinatorial libraries [18. The number of compounds accessible by combinatorial synthesis often exceeds the number of compounds which can be syiithcsii ed... 

Memfield s concept of a solid phase method for peptide synthesis and his devel opment of methods for carrying it out set the stage for an entirely new way to do chem ical reactions Solid phase synthesis has been extended to include numerous other classes of compounds and has helped spawn a whole new field called combinatorial chemistry Combinatorial synthesis allows a chemist using solid phase techniques to prepare hun dreds of related compounds (called libraries) at a time It is one of the most active areas of organic synthesis especially m the pharmaceutical industry... 

Centerpieces of combinatorial concepts include the synthesis of compound libraries instead of the preparation of single target compounds. Library synthesis is supplemented by approaches to optimize the diversity of a compound collection (diversity-oriented synthesis) and by efforts to create powerful interfaces between combinatorial synthesis and bioassays. 

The condensation between enaminones and cyanoacetamide is a well-established method for the synthesis of 2-pyridones (see c, Scheme 2, Sect. 2.1), and the use of malonodinitrile instead of the amide component has also been shown to yield 2-pyridones [39-41]. Recently, Gorobets et al. developed a microwave-assisted modification of this reaction suitable for combinatorial synthesis, as they set out to synthesize a small library of compounds containing a 2-pyridone scaffold substituted at the 3, 5, and 6-positions [42]. The 2-pyridones were prepared by a three-component, two-step reaction where eight different carbonyl building blocks were reacted with N,N-dimethylformamide dimethyl acetal (DMFDMA) to yield enaminones 7 (Fig. 2). The reactions were performed under solvent-free conditions at el-... 

The objective of traditional multistep synthesis is the preparation of a single pure compound, but combinatorial synthesis is designed to make many related molecules.57 The purpose is often to have a large collection (library) of compounds for evaluation of biological activity. A goal of combinatorial synthesis is structural diversity, that is, systematic variation in subunits and substituents so as to explore the effect of a range of structural entities. In this section, we consider examples of the application of combinatorial methods to several kinds of compounds. 

Jacobsen proposed a related heterogeneous catalyst in which the complex is bound via an ester linkage to commercial hydroxymethylpolystyrene beads. Such catalysts are of value not only in large-scale processes, but also in the combinatorial automated synthesis of libraries of new compounds.180... 

MATHEY Phosphorus-Carbon Heterocyclic Chemistry The Rise of a New Domain McKILLOP Advanced Problems in Organic Reaction Mechanisms OBRECHT Solid Supported Combinatorial and Parallel Synthesis of Small-Molecular-Weight Compound Libraries... 

Parallel processing of synthetic operations has been one of the cornerstones of medicinal and high-throughput synthesis for years. In the parallel synthesis of compound libraries, compounds are synthesized using ordered arrays of spatially separated reaction vessels adhering to the traditional one vessel/one compound philosophy. The defined location of the compound in the array provides the structure of the compound. A commonly used format for parallel synthesis is the 96-well microtiter plate, and today combinatorial libraries comprising hundreds to thousands of compounds can be synthesized by parallel synthesis, often in an automated fashion. 

Applications of the cross-metathesis reaction in more diverse areas of organic chemistry are beginning to appear in the literature. For example, the use of alkene metathesis in solution-phase combinatorial synthesis was recently reported by Boger and co-workers [45]. They assembled a chemical library of 600 compounds 27 (including cisttrans isomers) in which the final reaction was the metathesis of a mixture of 24 oo-alkene carboxamides 26 (prepared from six ami-nodiacetamides, with differing amide groups, each functionalised with four to-alkene carboxylic acids) (Eq.27). 

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