1,2,4-Triazolo[2,3-h]-7,9-thiaza-11-crown-4.

The title compound, 4,7-dioxa-10-thia-1,12,13-triazabicyclo[9.3.0]tetradeca-11,13-diene, C(8)H(13)N(3)O(2)S, contains an 11-membered ring, which appears in a chair conformation and has approximate mirror symmetry. It may be used for the complexation of metal atoms.

4-Acetonylidene-1-ethyl-2,3,4,5-tetrahydro-1H-1,5-benzodiazepin-2-one.

The title compound, C(14)H(16)N(2)O(2), contains a diazepine ring, which appears in a boat conformation. An intramolecular hydrogen bond is formed between the NH group of the diazepine ring and a carbonyl O atom of one of the side chains.