New methodology for automated SPOT synthesis of peptides on cellulose using 1,3,5‐triazine derivatives as linkers and as coupling reagents

Two new rigid bi‐aromatic linkers for synthesis of peptide arrays by SPOT methodology were obtained from cellulose treated with 2,4‐dichloro‐6‐methoxy‐1,3,5‐triazine. Reaction with m‐phenylenediamine gave non‐cleavable TYPE I linker which enabled attachment of the peptides via resistant to harsh reaction conditions amide, ether, and amine bonds. Reaction with 3‐Fmoc‐aminobenzoic acid followed by thermal isomerization of the intermediate “superactive” ester producing an amide‐like bond gave TYPE II linker that was very stable during peptide synthesis. However, the peptide was cleavable, with fragment of the linker, in the presence of 1 M LiOH solution. The uniform loading of the cellulose and efficient synthesis of the peptide array was achieved by using N‐(4,6‐dimethoxy‐1,3,5‐triazin‐1‐yl)‐N‐methylmorpholinium 4‐toluenesulfonate as the coupling reagent.