Hydrolysis of 2-aryl-4h-3, 1-benzoxazin-4-ones

2-Aryl-4H-3, 1-benzoxazin-4-ones were subjected to alkaline hydrolysis in O¹⁸-enriched water. It was established on the basis of data from mass-spectrometric analysis of the hydrolysis products that the C-2 and C-4 atoms of the benzooxazinone ring undergo nucleophilic attack. The primary direction of attack depends on the nature and position of the substituent.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 641–644, May, 1976.     

Container compounds — stable systems

We have studied the question of the stability of container compounds. As stability criteria we use the lifetime of the container compound. Quantitative estimates were obtained by drawing on the theory of quasistationary (resonance) states. The energy levels and the lifetimes for these levels, which are the lifetimes for the container compounds, are calculated with subsequent consideration of the Schrödinger equation. Numerical characteristics are obtained for various container compounds.Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 21, No. 2, pp. 207–211, March–April, 1985.     

Mononitration of derivatives of benzisatins

The mononitration of benz[e]-, benz[f]-, and benz[g]isatins and their tetrahydro derivatives was realized. It was established on the basis of an analysis of the ¹H NMR and mass spectra that substitution takes place at position 5 in the derivatives of the [g] series and at the position adjacent to the NH group in derivatives of the [f] series and in the case of 6,7,8,9-tetrahydrobenz [e]isatin. This reaction path corresponds to the maximum electron density in the HOMO, calculated by the CNDO method. In benz[e]isatin, contrary to the general relationship and to the quantum-chemical prediction, the nitro group initially enters the ring annellated with the indole ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 60–65, January, 1989.     

The copper(II) acetate complex with 2-(2-Hydroxyphenyl)-4,4-diphenyl-1,2-dihydro-4H-3,1-benzoxazine

The Cu(II) acetate complex with 2-(2-hydroxyphenyl)-4,4-diphenyl-1,2-dihydro-4H-3,1-benzoxazine (L) was synthesized for the first time and structurally studied by X-ray diffraction. The complex crystallizes as two crystallographically independent centrosymmetric binuclear molecules [Cu₂(μ-L)₂Ac₂] of similar structure, where L occurs as azomethin tautomeric form. The ligand performs tridentate chelate-bridging function. Each Cu atom exhibits extended tetragonal-pyramidal coordination by two O atoms and the N atom of one ligand L in the equatorial plane and by the O atom of the second ligand L in the axial position. The fourth equatorial position in the metal coordination polyhedron is occupied by the O atom of monodentate terminal acetate group.     

Low-temperature study of the molecular and crystal structures of 2-(2′-tosylamino-5′-nitrophenyl)-4H-3,1-benzoxazin-4-one, an organic luminophore

The crystal structure of 2-(2′-tosylamino-5′-nitrophenyl)-4H-3,1-benzoxazin-4-one (I) is studied by X-ray diffraction at 100 K (C₂₁H₁₅N₃O₆S, a = 20.899(2) Å, b = 10.948(1) Å, c = 8.260(1) Å, V = 1889.3(1) ų, Z = 4, and space group Pbn2₁). The compound exhibits an anomalous Stokes shift. Upon cooling, the oxazineaminophenyl fragment of compound I acquires a quinoid structure and the linear parameters of the intramolecular N-H?N hydrogen bond increase (the distance between the heterocyclic nitrogen atom and the hydrogen atom of the tosylamino group becomes 1.92 Å). The complete optimization of the geometry of molecules in compound I and unsubstituted 2-(2′-tosylaminophenyl)-4H-3,1-benzoxazin-4-one in the ground singlet electronic state is performed by the semiempirical method with the MOPAC program. It is shown that the oxygen atoms in the sulfo group of molecule I are nonequivalent, because one of them is involved in the intermolecular C-H?O hydrogen bond.