Combinatorial template

Demers, L. M. Mirkin, C. A., Combinatorial templates generated by dip-pen nanolithography for the formation of two-dimensional particle arrays, Angew. Chem. Int. Ed. 2001, 40, 3069-3071... 

In a related approach, Bartlett presented a system that compared the diversity of different combinatorial templates using the angles between the bond vectors connecting the core to the substituent. The method followed the spirit of the Caveat approach, and the results were presented In a visual form. 

The head-to-tail-coupling reactions described above are potentially useful in the design of dynamic combinatorial libraries. Features of these reactions include the rapid and reversible formation of carbon-carbon bonds, multifunctional ene-imine building blocks, and formation of stereo centers upon ene-imine linkage. Support for template-directed synthesis utilizing ene-imine building blocks is the formation of a poly ene-imine species that could recognize 3 -GGA-5 sequences of DNA.48 It is noteworthy that some polyene-imines are helical and could form a triple helix with DNA. 

Ralph, J. Brunow, G. Harris, P. J. Dixon, R. A. Schatz, P F. Boerjan, W. Lignification Are lignins biosynthesized via simple combinatorial chemistry or via proteinaceous control and template replication In Advances in Polyphenols Research Daayf, F. El Hadrami, A. Adam, L. Ballance, G. M.,Eds. Blackwell Publishing Oxford, UK, 2008, pp. 36-66. 

Wu and Sun have presented a versatile procedure for the liquid-phase synthesis of 1,2, ,4-tctrahydro-/i-carbolines [77]. After successful esterification of the MeO-PEG-OH utilized with Fmoc-protected tryptophan, one-pot cyclocondensations with various ketones and aldehydes were performed under microwave irradiation (Scheme 7.68). The desired products were released from the soluble support in good yields and high purity. The interest in this particular scaffold is due to the fact that the l,2,3,4-tetrahydro-/f-carboline pharmacophore is known to be an important structural element in several natural alkaloids, and that the template possesses multiple sites for combinatorial modifications. The microwave-assisted liquid-phase protocol furnished purer products than homogeneous protocols and product isolation/ purification was certainly simplified. 

D. L. Boger, C. M. Tarby, P. L Myers, L H. Caporale, Generalized Dipeptidomimetic Template Solution Phase Parallel Synthesis of Combinatorial Libraries , J. Am Chem. Soc. 1996,118,2109. 

Hydrogen-Bonding Templates in Dynamic Combinatorial Libraries 120... 

In the following sections, examples of hydrogen-bonding templates for the synthesis of macrocycles, cages, interlocked species, helicates and for the photochemical reaction of olefins will be discussed. The use of hydrogen-bonding templates in dynamic combinatorial libraries will also be presented. 

Chemical templates are being increasingly employed for the development of dynamic combinatorial libraries (DCL) [94-98]. These (virtual) libraries of compounds are produced from all the possible combinations of a set of basic components that can reversibly react with each other with the consequent potential to generate a large pool of compounds. Because of the dynamic equilibria established in a DCL, the stabilization of any given compound by molecular recognition will amplify its formation. Hence the addition of a template to the library usually leads to the isolation of the compound that forms the thermodynamically more stable host-guest complex (see Scheme 37). 

Scheme 40 Synthesis of receptor 80-S-S-80 from a dynamic combinatorial library based on 80-SH and 81-SH. The receptor is amplified in the presence of a tripeptide template...

Recent developments in zeolite synthesis and new materials include (i) the use of combinatorial methodologies, microwave heating, multiple templates or SDAs and concentrated fluoride media in synthesis, (ii) synthesis using the charge density mismatch (COM) concept, (iii) synthesis in ionothermal media, (iv) synthesis with complex designer templates or SDAs, (v) synthesis of nanozeohtes, (vi) zeoUte membranes and thin films (vii) and germanosilicate zeoHtes [76]. Several of these developments are discussed here. 

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