Preparation,spectral studies and X-ray crystal structure of 1,3,5-triphenyl-1,5-pentanedione,C23H20O2

1,3,5-triphenyl-1,5-pentanedione, C₂₃H₂₀O₂, has been prepared and characterized by spectroscopic methods and single crystal X-ray analysis. Crystals are monoclinic, space groupP2₁/n, a=28.124(4),b=5.997(1),c=10.434(1)Å, -98.42(1)Å,Z=4. The structure has been refined to a finalR-value of 0.040 for 1625 reflections withF _o>3(F _o). The compound contains the two carbonyl groups in a mutuallycis arrangement.     

Synthesis,spectral, X-ray diffraction and DFT studies on 1-(2-methyl-2-propenyl)-3-(2,3,4,5,6-pentamethylbenzyl)benzimidazolium chloride hydrate

A new benzimidazole based N-heterocyclic carbene (NHC) salt (1) was synthesized by the reaction of benzimidazole precursor with alkyl halide. The structure of 1 was determined by elemental analysis, FT-IR, ¹H NMR and ¹³C NMR spectroscopy tecniques and X-ray crystallography. The compound crystallized in the triclinic space group P-1 with two molecules in the unit cell. The optimization of 1 was firstly performed at B3LYP/6-311G++(d,p) level, then the theoretical spectral studies performed and compared with the experimental values. Besides the frontier molecular orbital energies and chemical reactivity analysis of 1, together with the electrostatic potential and molecular electrostatic potential analyses were performed at the same level of theory.     

The crystal and molecular structure of (−)—Crinine (C16H17NO3)

(–)—Crinine, C₁₆H₁₇NO₃, is an alkaloid extracted from the bulbs of Pancratium maritimum L. (Amaryllidaceae). The compound crystallizes in the space group P2₁2₁2₁ with cell dimensions a = 6.040(1), b = 12.382(1), c = 17.861(2) Å, with Z = 4. The molecule has five rings and an OH group. The N-containing, five-membered ring and the D ring have envelope conformations. The A and B rings have distorted chair and half-chair conformations, respectively.     

X-ray crystal structure and spectroscopy of a pseudo-square pyramidal Cu(II) complex, trans-dinitratotetrakis (trans-4-styrylpyridine)copper(II)

Single crystals of the title Cu(II) complex, [Cu(stpy)₄(ONO₂)(ONO₂)] [stpy = trans-4-styryl-pyridine] have been prepared and characterized by elemental and thermal analyses, IR, electronic and EPR spectral measurements, and X-ray crystal structure determination. The complex crystallizes in the monoclinic space group P2₁/c with unit-cell parameters, a = 12.985(2), b = 22.865(8), c = 17.024(10) Å, = 112.29(3)°, and Z = 4. The structure consists of discrete monomeric units of [Cu(stpy)₄(ONO₂)(ONO₂)]. The equatorial positions of the Cu(II) polyhedron are occupied by nitrogen atoms of the four stpy ligands and the axial positions by the oxygens of two unidentate nitrate anions. One of these oxygens is at rather longer distance [2.609(3) Å] and may be considered to be semicoordinated. If this semibond is ignored, the coordination geometry lies closer to an idealized square pyramid than to the trigonal bipyramid geometry. IR spectra reveal nitrogen coordination from stpy and asymmetry in the monodentate oxygen binding of the two nitrate ligands. The optical reflectance band at 600 nm suggests pseudo-square-based pyramidal geometry around Cu(II). Well-resolved Cu(II) hyperfine features in the EPR spectra reveal the absence of exchange interactions between adjacent copper centers. Optical and EPR spectra of a methanolic solution of the complex indicate solvent interactions. Thermogravimetric analysis shows the complex to be stable up to 175°C.     

The synthesis and crystal structure of new 3,6-bis[1-(4-ethoxyphenyl)-5-methyl-1,2,3- triazol-4-yl]-<Emphasis Type="Italic">s</Emphasis>-triazolo[3,4-b]-1,3,4-thiadiazole

The 3,6-bis[1-(4-ethoxyphenyl)-5-methyl-1,2,3-triazol-4-yl]-s-triazolo[3,4-b]-1,3,4-thiad- iazole was synthesized from p-ethoxyaniline to 8 with 1-(4-ethoxyphenyl)-5-methyl-1,2,3-triazol-4-caroxylic acid. The yielded product 9 was investigated with X-ray crystallographic, NMR, MS, and IR techniques. Compound 9, C₂₅H₂₄N₁₀O₂S, Mr = 528.60, crystallizes in the triclinic space group P < eqid1 > . V = 1276.6(4) ų, Z = 2, Dx = 1.375 Mgm^–3. The final R was 0.0589.     

Synthesis and crystal structures of 2-amino-3-cyano-4-(2-chlorophenyl)-1,4-dihydro-2H-pyrano[3, 2-h]quinoline and 2-amino-3-cyano-4-(2-chlorophenyl)-8-(2-chlorobenzylidene)-1,4,5,6,7,8-hexahydrobenzo[b]pyran

The title compounds 2-amino-3-cyano-4-(2-chlorophenyl)-1,4-dihydro-2H-pyrano[3, 2-h]quinoline 1 (C₁₉H₁₂ClN₃O, M _r = 333.77) and 2-amino-3-cyano-4-(2-chlorophenyl)-8-(2-chlorobenzylidene)-1,4,5,6,7,8-hexahydrobenzo[b]pyran 2 were synthesized and crystallized. The crystals of compound 1 are triclinic, space group P-1, a = 7.488(2), b = 9.127(3), c = 12.252(3) Å, = 73.58(2), = 78.38(2)°, = 75.39(2), Z = 2, V = 769.5(4) ų; The compound 2 crystallizes in space group P2₁/n, with cell parameters a = 13.582(2), b = 8.974(1), c = 16.960(2) Å, = 103.34(1)° and D _calc = 1.352 g/cm^–3 for Z = 4. X-ray analysis reveals that atoms C(1)—C(5) and O form a pyran ring in compound 1, which adopts half-chair conformation. In compound 2 the atoms C(12)—C(16) and O form a pyran ring which adopts boat conformation, another six-membered ring (C(8)—C(13)) adopts a half-chair conformation. In addition, there are intermolecular hydrogen bonds in the crystal structures 1 and 2.     

Crystal structures of 2,4,9-trimethyl-(3ar,4c,9c,9ac)-3a,4,9,9a-tetrahydro-benzo[?] isoindole-1,3-dione(endo), C15H17NO2 (1), and 2-methyl-(3ac,9ac)-3a,4,9,9a-tetrahydro-4r,9c-ethano-benzo[?]isoindole-1, 3-dione(endo), C15H15NO2 (2)

The title compounds crystallize in the space group P-1 (compound 1), with a = 7.198(2) Å, b = 7.965(2) Å, c = 12.707(2) Å, α = 72.05(1)^∘, β = 87.65(2)^∘, γ = 65.18(2)^∘ and Pbca (compound 2), with a = 8.156(3) Å, b = 13.177(3) Å, c = 22.742(4) Å. The chiral centers in both compounds C3a, C4, C9, C9a are either R, S, R, S or S, R, S, R (compound 1) and either R, R, S, S or S, S, R, R (compound 2) because of the centric space group.     

Synthesis and X-ray Structure of (2R, 3R, 4R, 5R)-3,4,5-Tris-Benzyloxy-2-Benzyloxymethyl-Piperidin-1-ol, the N-Hydroxy-Analogue of 2,3,4,6-Tetra-O-Benzyl-1-Deoxymannojirimycin

Abstract  The title compound 8 was obtained for the first time by hydride-mediated reduction of the d-fructose-derived nitrone 9. The N-hydroxy piperidine 8 is a precursor of the N-hydroxy analogue of DMJ, a potent inhibitor of α-mannosidases. It was isolated as colorless crystals (triclinic, P1 space group) exhibiting the following cell parameters: a = 9.947(2) ?; b = 12.155(2) ?; c = 13.864(5) ?; α = 100.98(3)°; β = 97.94(2)°; γ = 109.50(1)°. The X-ray analysis of a monocrystal of 8 allowed confirmation of its relative configurations and showed the anti orientation of its N-hydroxy group. This structural feature should be useful for considering the interaction of N-hydroxy iminosugars with the recognition site of carbohydrate processing enzymes. Index Abstract  The title compound 8 was prepared for the first time by hydride-mediated reduction of the d-fructose-derived nitrone 9. Compound 8 is a precursor of the N-hydroxy analogue of DMJ, a potent inhibitor of α-mannosidases. The X-ray analysis allowed confirmation of the relative configurations of 8 and showed the anti orientation of its N-hydroxy group. This structural feature will be useful for considering the interaction of N-hydroxy-iminosugars with specific biological targets.