Compound 6

(E)-3-(4-(2-((6-((2,2-Diethoxyethyl)amino)-6-oxohexyl)amino)-2-oxoethoxy)styryl)-5,5-difluoro-7-(1H-pyrrol-2-yl)-5H-dipyrrolo[1,2-c:2',1'-f][1,3,2]diazaborinin-4-ium-5-uide

From: A red-shifted fluorescent substrate for aldehyde dehydrogenase