Springer Verlag, Russian Chemical Bulletin, 2(62), p. 492-496
DOI: 10.1007/s11172-013-0068-3
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An acid-catalyzed reaction of 2-methylbenzoxazole with 3,4,5,6-tetrachloro-1,2-benzoquinone leads to 2-(benzoxazol-2-yl)-5,6,7-trichloro-1,3-tropolone and 2-(benzoxazol-2-yl)-4,5,6,7-tetrachloro-1,3-tropolone. 1,3-Tropolones upon reflux in ethyl alcohol undergo the rearrangement resulted in the seven-membered ring contraction to form ethyl 2-(benzoxazol-2-yl)-5,6-dichloro-3-hydroxybenzoate and ethyl 2-(benzoxazol-2-yl)-4,5,6-trichloro-3-hydroxybenzoate. The molecular structure of the latter was established by X-ray diffraction analysis.