10-Hydroxy-7-arylindeno[1,2-b]-1,2,5-oxadiazolo[3,4-d]pyridines and 7-Aryl-10-oxoindeno[1,2-b]-1,2,5-oxadiazolo[3,4-d]pyridines— Synthesis, Spectra, and Polymorphism
作者:Shuntaro Mataka、Hideki Gorohmaru、Thies Thiemann、Tsuyoshi Sawada、Kazufumi Takahashi、Akiyoshi Tori-i
DOI:10.3987/com-98-s(h)88
日期:——
The novel dyes 7-aryl-10-oxoindeno[1,2-b]-1,2,5-oxadiazolo[3,4-d]pyridines (4) and 7-aryl-10-hydroxyindeno[1,2-b]-1,2,5-oxadiazolo[3,4-d]pyridines (5) have been prepared from acetophenone derivatives. While compounds (4) exhibit a dark red color, they are only weakly fluorescent Compounds (5) is fluorescent. Of interest is that 10-hydroxy-7-phenylindeno-[1,2-b]-1,2,5-oxadiazolo[3,4-d] pyridine (5a) can take four polymorphic forms in the solid state, of which two are yellow (designated as 5a-Y-1 and 5a-Y-2) and two are red (5a-R-1 and 5a-R-2). Two of them are interconvertible (yellow/red) upon exposure to different solvents. X-Ray crystal structure analysis of 5a-R-2 shows the phenyl ring and the indenooxadiazolopyridine ring to be coplanar.