The stability of IP + MPs to acid, basic, oxidizing and reducing conditions was evaluated by incubating the macrocycles with 5 mM NaIO4, sodium dithionite (Na2S2O4), or triisopropyl silane (TIPS) at 37 o C for 24 hours. Again, no products were observed by LC-MS. Finally, the macrocycles were incubated in in buffers with pH values ranging from 1 to 11. LC-MS analysis showed the macrocycles to be stable under all of these conditions. The primary data for all of these experiments is shown in Supplementary Figures .