Solid spot synthesis

Jobron, L. and Hummel, G. (2000) Solid-phase synthesis of unprotected N-glycopeptide building blocks for SPOT synthesis of glycopeptides. Angew. Chem. Inti Ed. 39, 1621-1624. 

Volkmer-Engert, R., Hoffmann, B., and Schneider-Mergener, J. (1997) Stable attachment of the HMB-linker to continuous cellulose membranes for parallel solid phase spot synthesis. Tetrahedron Lett. 38, 1029-1032. 

Besides classical resin beads, other polymeric carriers were also used for the synthesis ofpeptide libraries in various formats. Poly aery late-grafted polypropylene pins were used for the synthesis of the first combinatorial chemical library [1,2], This type of support continues to be heavily used in multiple peptide [27] and non-peptide [28] library synthesis. Cellulose paper, originally used by Frank et al. as a solid-phase support for oligodeoxy-ribonucleotide synthesis [29], has also been used as the support for multiple SPOT synthesis of peptide libraries [30,31], Polystyrene-grafted polyethylene film (PS-PE) may also be used in combinatorial peptide library synthesis [32], The specific feature of the membrane type of carrier is its dividability. This feature has been used for the synthesis of libraries with a nonstatistical distribution of library members, where no compound is missing and none is represented more than once [33],... 

Adler, F., Turk, G., Frank, R., et al. (2000) A new array format for the automated parallel combinatorial synthesis by the SPOT-technique. In Innovation and Perspectives in Solid Phase Synthesis (Epton, R., ed.), Mayflower Worldwide, Kings-winford, UK, pp. 221-222. 

A peptide library can be synthesized using the SPOT synthesis technique to form a low-density peptide spot array (e.g., 25 spots/cm ). In this method, different peptides are synthesized in situ as low-density arrays on cellulose membrane or paper (8). The volume of Fmoc-amino acids and coupling reagents dispensed creates a specific SPOT size that determines both the scale of reaction and the absolute number of peptides that can be arranged on an area of a membrane. Cotton (another form of cellulose) and polystyrene-grafted polyethylene film segments also have been used as solid supports. Recently, polymeric membranes that are chemically, mechanically, and thermally more stable have been developed, which include hydroxy-functionalized PEG acrylate polypropylene membranes and an amino-functionalized ester-free PEG... 

The spot synthesis technique is simple and easily accessible for practical use. There are some limitations to the scope of chemistries that can be used with cellulose as a solid support. To eliminate some of these shortcomings, Gao and EsnoufP° 4 proposed using a different membrane, Immobilon AV-1, for spot synthesis. Before the synthesis of peptide arrays can be carried out, this polyvinylidene fluoride based material is derivatized with ethane-1,2-diamine, followed by coupling of Fmoc-(3Ala as a spacer. In most other aspects, this peptide array synthesis is very similar to the spot synthesis proposed by Frank.t l... 

Spot synthesis Solid-phase synthesis at certain points (spots) on u (wo-dimensionul (2D) surface (e.g.. a cellulose membrane). Recently, (he techniques of ink-jet printing have been applied to spot synthesis, yielding very den.se arrays of compounds. 

Template-associated synthetic proteins (TASP), proteins that have been designed and synthesized de novo. Artificial tertiary structures can be constructed by covalent attachment of secondary structure building blocks, e.g., /3-sheets, a-helices, and turns, to a topological template. This results in a non-linear architecture of protein modules that is nevertheless able to mimic native proteins. The combination of different secondary structure motifs in TASP provides, e.g., /Sa/3-structures, helix-bundles, or /3-barrel tertiary structures. The design of TASP makes extensive use of molecular modeling techniques. Solid-phase synthesis and spot synthesis have been used to obtain TASP [G. Tuchscherer, M. Mutter,... 

A novel concept for the synthesis of macrocyclic peptidomimetics 262, which incorporate heteroaromatic units, was reported (Scheme 39). This method involves sequential SNAr reactions of orthogonally protected amino groups of peptides and other linear oligomers on halogenated heterocycles such as 2,4,6-trichloro[l,3,5]triazines. The scope of this novel solid-phase approach was evaluated systematically by means of the SPOT-synthesis methodology on planar cellulose membranes <2000JC0361>. 

SPOT-synthesis is a facile and very flexible technique for the simultaneous parallel solid phase chemical synthesis. Series of compounds or compound... 

Paper as a solid support fascinated Frank, and he later developed another unique and ingenious technique, the spot synthesis (SPOT). In SPOT synthesis, peptides are synthesized on functionalized membrane sheets as spots that could be as large as 10 mm or as small as 1 mm. The spot synthesis technique became a popular tool for peptide synthesis and was soon automated." The first semiautomated SPOT synthesizer, the ASP222, was launched by ABIMED Analysen-Technik of Germany in 1993." The automated method provided an economical way to synthesize very large numbers of peptides. The Intavis synthesizer Auto-Spot (www.intavis.com) allowed the simultaneous synthesis of 1600 peptides. The chemical and physical problems associated with the use of cellulose sheets as synthesis support were, for the most part, overcome by developing synthetic membranes from polypropylene and Teflon. ... 

In the late 1980s, Frank and coworkers developed a method for parallel solid phase synthesis where the molecules were linked to a membrane rather than to conventional polystyrene beads [26,27]. Libraries were prepared by adding the different reagents at each of the spots on the membrane. This SPOT-synthesis method can be carried out on cellulose and polypropylene sheets (loading lOO-lOOOOnM/cm or lO-lOOnM/cm, respectively) and requires no specialized infrastructure to obtain libraries. The mean spot size... 

The residue is triturated with methanol to afford a crystalline solid. This material contains no detectable amount of starting material by paperstrip chromatography but shows two UV absorbing spots near the solvent front (methanol-formamide 2 1 vs benzene-n-hexane 1 1). An aliquot is recrystallized three times from a mixture of benzene and n-hexane to give 17a,20,20,21-bis(methylenedioxy)-11(3-hydroxy-6,16a-dimethyl-4,6-pregnadiene-3-one which is used in the subsequent step of the synthesis without further purification. 

Abstract Current microwave-assisted protocols for reaction on solid-phase and soluble supports are critically reviewed. The compatibility of commercially available polymer supports with the relatively harsh conditions of microwave heating and the possibilities for reaction monitoring are discussed. Instrmnentation available for microwave-assisted solid-phase chemistry is presented. This review also summarizes the recent applications of controlled microwave heating to sohd-phase and SPOT-chemistry, as well as to synthesis on soluble polymers, fluorous phases and functional ionic liquid supports. The presented examples indicate that the combination of microwave dielectric heating with solid- or soluble-polymer supported chemistry techniques provides significant enhancements both at the level of reaction rate and ease of purification compared to conventional procedures. 

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