(S)-2'-azido-7'-methoxy-5H-spiro[oxazole-4,9'-xanthen]-2-amine

(R)-2-amino-2'-bromo-5H-spiro[oxazole-4,9'-xanthen]-7'-ol

(S)-2-amino-7'-(pyridin-3-yl)-5H-spiro[oxazole-4,9'-xanthen]-2'-ol

N-((4S)-2-amino-7'-methoxyspiro[1,3-oxazole-4,9'-xanthen]-2'-yl)-5- chloro-2-pyridinecarboxamide

(S)-N-(2'-azido-7'-methoxy-5H-spiro[oxazole-4,9'-xanthene]-2-yl)-2,2,2-trifluoroacetamide