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Publication of BE626590ApublicationCriticalpatent/BE626590A/xx
C07D273/00—Heterocyclic compounds containing rings having nitrogen and oxygen atoms as the only ring hetero atoms, not provided for by groups C07D261/00 - C07D271/00
C07D273/02—Heterocyclic compounds containing rings having nitrogen and oxygen atoms as the only ring hetero atoms, not provided for by groups C07D261/00 - C07D271/00 having two nitrogen atoms and only one oxygen atom