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Free keywords:
heterocycles; cyclotetramerization; macrocycles; photodimerization
Abstract:
The new cyclic quaterbenzoxazole 5 and -imidazole 8 have been synthesized by cyclization of 3-amino-2-hydroxybenzamide (4) and the ammonium salt of 2,3-diaminobenzoic acid (7), respectively, with polyphosphoric acid. Both compounds represent a new heterocyclic nine ring system, which can be built up from four identical (or different) benzo-x-azoles in a cyclic arrangement.
