Solid phase syntheses of peptoid like arylureido compounds and sequencing of isobars without molecular encoding

Arylureido-backbone containing peptoid-like trimers were prepared using the one-bead-one-compound approach. Isobaric molecules were synthesized from isocyanate precursors that contain alkyl halide handles at the ortho and para -positions in the phenyl ring. After chain extension with a primary amine, the piperazine-capped molecules were sequenced using tandem mass spectrometry and successfully identified based on their fragmentation pattern without a need for internal molecular encoding. Isobaric arylureido peptoids undergo SS1 and SS2 fragmentations in MALDI-TOF MS/MS, thus offering a sequencing mechanism for arylureides without molecular encoding.