Bibenzoxazole, Bibenzothiazole

These two compounds are readily available by condensation of o-amino (thio)phenol with oxalic acid derivatives. 2,2 -Bibenzoxazole (80) was first prepared more than 70 years ago, but was incorrectly formulated as a benzoxazinobenzoxazine (25HCA16). It is readily prepared by oxidation. 

80 have also been studied (72JA2414 82MI1). Reaction of 80 with lithium aluminium hydride results in ring opening to an ethylene diamine derivative [72LA(765)110], 

Several spectroscopic (71CJC956 78MI2 93SPL1771) and electrochemical (82MI1) studies have been reported on 81. Like its oxygen analogue, 

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