Crystal and molecular structure of 1-(3,5-dimethyl-2-furyl)-3-(p-tolyl) -prop-2-en-1-one

The structure of 1-(3,5-dimethyl-2-furyl)-3-(p-tolyl)-prop-2-en-1-one, C₁₆H₁₆O₂ is determined by single-crystal x-ray diffractometry. Crystals are triclinic, , a=7.381(7), b=8.871(5), c=10.745(13) Å, =93.53(7), =102.25(8),=95.43(7)°, V=682(1) ų, Z=2, d_calc=1.170 g cm^–3, (Cu K)=1.54178 Å,=5.697 cm^–1, M=270.30, F(000)=256, R=0.077 for 1601 unique observed reflections. The trans-geometry of the C=C double bond, thes-cis-geometry of the C=C-C=O moiety, and thes-trans arrangement of the carbonyl and furane oxygen atoms are proved.     

Crystal and molecular structure of 2-(2′-methylaminophenyl)-4H-3,1-benzoxazine-4-one

A planar structure for molecules of 2-(2-methylaminophenyl)-4H-3,1-benzoxazine-4-one was found by x-ray structural analysis. Shortening of the N-Ph bond and lengthening of the distance between amino- and azine-N atoms in comparison to the tosyl analog was demonstrated to lead to a bathochromic shift of the absorption spectrum and a hypsochromic displacement of the luminescence spectrum. As a result, the Stokes shift of 2-(2-methylaminophenyl)-4H-3,1-benzoxazine-4-one is smaller than that of 2-(2-tosylaminophenyl)-4H-3,1-benzoxazine-4-one. In the crystal, molecules of 2-(2-methylaminophenyl)-4H-3,1-benzoxazine-4-one are stacked with intermolecular interaction energy between molecules in the stack of –12.5 and –14.2 kcal/mole. The stacks are joined into layers parallel to (010).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1781–1785, August, 1989.     

Crystal structure of organosilicon compounds. XLVIII. N-(chlorodimethylsilylmethyl)-hexahydroazepin-2-one

Journal of Structural Chemistry -     

Crystal structure of 2-Se-(2-methyl-2-propenyl)-1-benzoic acid.

C11H12O2Se is triclinic, P1. Unit-cell dimensions at 293 K are a = 5.8450(10), b = 8.1490(10), c = 11.4620(10)A, alpha = 97.050(10), beta = 90.140(10), gamma = 90.120(10) degrees, V = 541.81(12)A3, Dx = 1.564 g/cm3, and Z = 2. The R value is 0.047 for 1388 observed reflections. The dihedral angle between the phenyl ring and the isobutenyl group is 72.3(2) degrees. There is an intermolecular hydrogen bond between two symmetry-related carbonyl groups with an O1...O2 distance of 2.669(6)A. The molecules in the crystal are packed at normal van der Waals distances.     

Crystal structure of trans(3R,2aS)-(-)-3-phenyl-hexahydro-oxazolo[3,2-a]pyridin-5-one.

Chiral, non-racemic hexahydro-oxazolo[3,2-a]pyridin-5-ones are strategic starting materials for the asymmetric synthesis of alkaloids, via the stereoselective C-C bond formation at the position a to the nitrogen atom. The stereoselectivity of this key step is mainly driven by the geometry of the fused rings of the oxazolopyridine moiety. In this work, the synthesis and X-ray structure of trans(3R,2aS)-(-)-3-phenyl-hexahydro-oxazolo[3,2-a]pyridin-5-one is reported.     

Crystal structure and quantum chemical calculations of (E)1-benzyl-3-((4-methoxyphenyl)imino)-5-methylindolin-2-one

The known Schiff base compound, (E)1-benzyl-3-((4-methoxyphenyl)imino)-5-methylindolin-2-one, was prepared as before by reacting 1-benzyl-5-methylindoline-2,3-dione with 4-methoxyaniline. The product was unambiguously characterized using elemental analysis, ¹H and ¹³C-NMR spectroscopy, and its new single-crystal X-ray structural analysis. Molecular orbital calculations were conducted in order to investigate the structures and relative stabilities of the (E) and (Z) isomers of 1-benzyl-3-([4 methoxyphenyl]-imino)-5-methylindolin-2-one. Specific attention was paid to the (E) isomer. The available crystallographic experimental data for the latter ensured also validation of the model structures computationally derived at the theoretical B3LYP/6-31G(d,p) level.