Esterification of the C-terminal fragment on 2-chlorotrityl chloride resin

1 Esterification of the C-terminal fragment on 2-chlorotrityl chloride resin 

Place 1 g of 2-chlorotrityl chloride resin in a round-bottomed flask and swell the resin using the minimum amount of DCM for 5 min. 

In the minimum amount of DMF, dissolve 1.5 M excess over the calculated quantity of the protected fragment that is required to achieve the desired loading. Add the peptide solution to the resin. 

Immediately transfer 20 i.l of the resin suspension into an Eppendorf vial containing 100 p-l DMF, and centribige. Use 5 p.1 of the supernatant solution for HPLC analysis and determine the peak area, which corresponds to the initial fragment concentration. 

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