A. Focused OBOC libraries structure; B. Focused library
synthesis. a) 1. Swelling in water for 24 h; 2. Fmoc-OSu (0.04 equiv), Alloc-OSu
(0.04 equiv.) and DIPEA, DCM/diethyl ether (55: 45), vigorously shaking 30min;
b) Boc2O (3 equiv), DIPEA (6 equiv) in DMF, 2 h c):
Pd(PPh3)4 (0.2 equiv), PhSiH3 (20 equiv) in
DCM, twice (30 min each); d) Ac-Gly-OH (3 equiv.), DIC (3equiv.) and HOBt (3
equiv.), 2h; e) 1. 20% piperidine in DMF, 2 x 10 min.; 2. 50%
TFA in DCM (2x30min); f) Split-mix combinatorial synthetic approach using
Fmoc-L-amino acids; Four grams resin was split into two focused libraries after
coupling of Fmoc-D-Cys(Trt)-OH; g) TFA: phenol: water: thioanisole: Tis
(10:0.5:0.5:0.5:0.25, v/w/v/v/v), 3 h; h) 500mL mixture of water, acetic acid
and DMSO (75:5:20, pH=6), shaking for 2 days. C. Chemical
structure of LXW64 and Biotinylated LXW64.