Pipetting 384-well parallel

Approximately 100 mg of resin was distributed to each of the reaetion bloek wells (of an ACT block or a Bohdan block) by pipetting a slurry of the resin in DMF/DCM (3 1) or as dry resin into each IRORI kan. The peptides were then assembled by the combinatorial chemistry apparatus suited for parallel or split-and pool-synthesis (34) using in situ neutralization/HBTU activation protocols for BOC chemistry. The resin was initially washed with DCM and the BOC protecting group removed by washing twice with a 40% solution of TFA in DCM. 

A similar experiment was performed in a 96-well plate format. The components of the polymerization mixture were the same except for the solvent (CH3CN was used instead of CH2C12). The polymerization was thermally initiated. The solutions were dispensed using a pipetting robot (Fig. 7.7) and the supernatants analyzed in series by HPLC-UV or in parallel with a plate reader. Eleven WellMIPs were prepared and screened for each monomer. As seen in Fig. 7.9, the reproducibility of the automated procedure is good and the fast parallel assessment delivers similar results as the serial analysis by HPLC. 

The execution of the parallel synthesis of up to 96 single compounds by the Multipin method involves pipetting the reactants to each well of a 96-well microtiter plate. The pin array is then placed on top of the plate and the resin is allowed to incubate with the reactants to perform the coupling step. The reaction temperature can be raised to 90°C by placing the reaction block into an incubator. Following each reaction step, the pin array is removed and treated in batch to wash the solid support. These operations are repeated until the desired combinatorial synthesis is completed. The resulting compounds can then be removed from the pins into individual wells on a microtiter plate, each of which ideally contains one single compound. 

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