Fig. 1: Diversification of macrocyclic scaffolds by combinatorially appending fragments to peripheral groups.

a General principle of the approach. b Image of an 80 nL droplet transferred by ADE, shown in a 96-well plate and next to a 4 μL droplet for scale. The droplets contain fluorescein for visualization by UV light. Addition of target and assay reagent to 80 nL macrocycle reactions dilutes the organic solvent to 0.4% which is compatible with bioassays. c Model macrocycle scaffold 1 containing a peripheral primary amine (blue) that is modified by acylation. d Reaction of model macrocycle 1 with indicated acids 1–8, quantified by HPLC (absorbance and/or ion count). The first number indicates conversion at 4 µL volume via pipetting with DIPEA. The second and third numbers indicate conversion at 80 nL via acoustic liquid transfer with DIPEA and DABCO, respectively. e Randomly selected non-peptide scaffolds containing less accessible amino groups (in blue).