Synthesis and Structure of 9-Bromo-2-fluoro-8-[ethyl, (E)-2-propenoate-3-yl]-6,7-dihydro-5H-benzocycloheptene

Abstract  

This paper reports a synthesis of 9-bromo, 2-fluoro substituted, and Z-ring locked (by a trimethylene bridge at C8 and C11) crystalline fluorine substituted bicyclic ring-fused polyene bearing a δ-bromo-α,β,γ,δ-unsaturated ester unit. It is a structural element found in sterically hindered retinoids and is a useful advanced intermediate in the total synthesis of these naturally occurring bioactive polyenes. The synthon, 8-fluoro-1-benzosuberone was converted into 9-bromo-2-fluoro-6,7-dihydro-5H-benzocycloheptene-8-carboxaldehyde chemoselectively and regioselectively and then into 9-bromo-2-fluoro-8-[ethyl, (E)-2-propenoate-3-yl]-6,7-dihydro-5H-benzocycloheptene in a step economical and stereoselective manner by treatment with triethylphosphonoacetate and NaH in THF. The process creates a new carbon–carbon double bond between C12 and C13 and produces a previously unreported product that has been characterized by X-ray, IR, ¹H NMR, ¹³C NMR, GC–MS, and elemental analysis. Crystals are triclinic, space group P-1, a = 7.581(2), b = 8.324(2), c = 11.759(3) ?, α = 96.723(17), β = 96.056(16), γ = 101.999(17)°, Z = 2.     

Synthesis,Spectral and Structural Studies of a Novel Semicarbazone Synthesized from Quinoline-2-Carboxaldehyde and N<Superscript>4</Superscript>-Phenyl-3-Semicarbazide

Abstract  

A new semicarbazone, HL has been synthesized from quinoline-2-carboxaldehyde and N⁴-phenyl-3-semicarbazide and structurally and spectrochemically characterized. ¹H NMR, ¹³C NMR, IR and electronic spectra of the compound are studied. The existence of keto form in the solid state is supported by the crystal structure and IR data. The compound crystallizes into an orthorhombic space group P2₁2₁2₁. Intra and intermolecular hydrogen bonding interactions facilitates unit cell packing in the crystal lattice.     

Synthesis and Crystal Structure of (5-Methyl-3-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)-[5-(<Emphasis Type="Italic">p</Emphasis>-tolylamino)-2<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-4-yl]methanone

Abstract  

(5-Methyl-3-phenyl-1H-pyrazol-1-yl)-[5-(p-tolylamino)-2H-1,2,3-triazol-4-yl]methanone was synthesized and characterized by ¹H NMR, MS and IR spectra data. The structure of title compound was identified by X-ray diffraction. Compound, C₂₀H₁₈N₆O, Mr = 358.40, crystallizes in the triclinic space group P-1 with unit cell parameters a = 10.303(6), b = 12.489(7), c = 15.305(9) ?, α = 108.489(12), β = 101.920(11), γ = 96.971(13)°, V = 1790.0(17) ?³, Z = 4, Dx = 1.330 mg/cm³. The final R was 0.0520.     

Crystal Structure of Diethyl[(4chlorophenyl)(dibenzylamino)methyl]propanedioate

Abstract  

The titled new functionalized N,O,O-ligand of type diethyl[(4-chlorophenyl)(dibenzylamino)methyl]propanedioate (4) is prepared in good yield through condensation of dibenzylamine, with 2-arylidene-malonic acid diethyl esters 3. The structure of 4 was determined by spectral (IR, ¹H NMR), elemental analyses and X-ray diffraction data. The molecular conformation shows two possible pockets ready to coordinate two metal atoms.     

Spectroscopic Studies and Crystal Structure of 1-(Morpholino (Phenyl) Methyl) Pyrrolidine-2,5-Dione

Abstract  

A new mannich base 1-(morpholino(phenyl)methyl)pyrrolidine-2,5-dione formed by the direct condensation of morpholine, succinimide and benzaldehyde has been synthesized. The structure of this mannich base has been elucidated on the basis of micro elemental analysis, IR, ¹H NMR, ¹³C NMR, UV–Visible Techniques and Mass. The crystal structure of the title compound C₁₅ H₁₈ N₂ O₃ was determined. It crystallizes in the triclinic system, space group P − 1, with a = 8.8122(13) ?, b = 9.2794(14) ?, c = 9.814 (3) ?, α = 107.154(9)°, β = 97.936(9)°, γ = 110.197(7)°,V = 693.4(2) ?³, D _x  = 1.314 Mg/m³. The structure was solved by the full-matrix least squares on F² and had a refined R value of 0.0486 for 8567 observed reflections. The six membered heterocyclic ring of the morpholino moiety adopts a chair conformation. The crystal structure is stabilized by weak intermolecular C–H···O interactions that link the molecules into inversion dimers.     

Synthesis and Crystal Structure Analysis of Methyl 2-Hydroxyimino-3-phenyl-propionate

Abstract  

As precursors of α-amino acids, methyl 2-hydroxyimino-3-phenyl-propionate (F.W. 193.20) was synthesized, characterized by ¹H NMR, IR, element analysis and confirmed by X-ray crystal structure analysis. This compound crystallizes in monoclinic class under the space group P2₁/c with cell parameters, a = 8.6435(17) Å, b = 5.4957(11) Å, c = 21.146(4) Å; β = 97.12(3)°, and Z = 4. The structure exhibits inter-molecular hydrogen bonds of the type O–H···N, O–H···O, C–H···O.     

Syntheses and Crystal Structures of Three Electron Poor N-Vinyltheophylline Derivatives

Abstract  

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and alkyl acetylenecarboxylates (or dialkyl acetylenedicarboxylates) by theophylline leads to vinyltriphenylphosphonium salts, which undergo Michael addition reaction with conjugate base to produce phosphorus ylides. Silica gel was found to catalyze conversion of the phosphorus ylides to electron-poor N-vinyl imidazoles in solvent-free conditions under thermal (90 °C, 1 h) conditions. The structures of these compounds were confirmed by IR, ¹H, and ¹³C NMR spectroscopy, and single crystal X-ray structure determination. The structural analysis of the products indicated that the reaction is completely regio- and stereoselective.     

Crystal Structure of a Trinuclear Mercury(II) Cyanide Complex of Tetramethylthiourea, [{(Tetramethylthiourea)2Hg(CN)2}2·Hg(CN)2]

Abstract  

The title compound was prepared by reacting mercury(II) cyanide and tetramethylthiourea (Tmtu) in the molar ratio of 1:1.75. It was characterized by IR and NMR (¹H and ¹³C) spectroscopy, and X-ray crystallography. The appearance of a band around 2,200 cm⁻¹ in IR and a resonance around 145 ppm in ¹³C NMR indicated the binding of cyanide to mercury(II). The crystal structure of the title complex, [{(tetramethylthiourea)₂Hg(CN)₂}₂·Hg(CN)₂] (1) consists of two independent [(Tmtu)₂Hg(CN)₂] moieties bridged by a Hg(CN)₂ unit. The mercury atom in [(Tmtu)₂Hg(CN)₂] unit is coordinated to two thione sulfur atoms of Tmtu and to two cyanide carbon atoms in a distorted tetrahedral mode.     

Synthesis and Crystal Structure of Bis(<Emphasis Type="Italic">N</Emphasis>-alkyl-<Emphasis Type="Italic">N</Emphasis>-phenyl dithiocarbamato)mercury(II)

Abstract  

The mixed ligand dithiocarbamate complex was synthesized by the reaction between the ammonium salt of the dithiocarbamate ligands with mercury salt. There are two mercury complexes in the asymmetric unit with a compositional disorder between an ethyl group and a methyl group. A distorted tetrahedral geometry is found for each mercury atom defined by four sulphur atoms derived from two asymmetrically chelating dithiocarbamate ligands. IR spectra show thioureide υ(C–N) bands at 1491 cm⁻¹ which is higher than observed in the simple complexes of the same ligands. The effect of alkyl substituents were observed in the magnetic unequivalence of the thioureide and phenyl units in the NMR spectroscopy. The molecules are related to each other by virtue of the compositional disorder which exists at three positions in the alkyl group across the unit. The compound crystallizes in the triclinic space group P-1 with a = 10.4764(10) ?, b = 11.0433(10) ?, c = 18.5566(17) ?, α = 97.8980(10)^°, β = 95.3340(10)^°, γ = 110.3010(10)^°, and Z = 2.     

Crystal Structure of 3-(4-Methoxy-benzylidene)-isothiochroman-4-one

Abstract  

The title compound, 3-(4-methoxy-benzylidene)-isothiochroman-4-one (C₁₇H₁₄O₂S) was prepared from the reaction of isothiochroman-4-one with benzaldehyde in the presence of small amount of HCl. The structure of the synthesised compound was determined by IR, ¹H NMR and X-ray crystallography. The structure was solved in monoclinic, space group P2₁/n with a = 3.9773 (7) Å, b = 10.918 (2) Å, c = 30.609 (6) Å, β = 90.615 (3)°, V = 1329.1 (4) Å³, Z = 4 and with R _int = 0.047. The bicyclic ring of isothiochroman-4-one moiety does not adopt a planar geometry. The molecular conformation is stable via C10–H···O1 and C16–H···S1 intramolecular hydrogen-bonding interactions. These contacts involve molecules in an extended two-dimensional sheet to the bc plane.     

Lewis Acid–Base Adduct Me3Sb–Ga(t-Bu)3

Abstract  

The simple Lewis acid–base adduct Me₃Sb–Ga(t-Bu)₃ 1 was prepared by reaction of t-Bu₃Ga and SbMe₃ in 1:1 M ratio. 1 was fully characterized by multinuclear NMR spectroscopy (¹H, ¹³C). In addition, its solid state structure was determined by single crystal X-ray diffraction studies. 1 is monoclinic, space group P2₁ /n with a = 8.4895(2) ?, b = 12.9303(4) ?, c = 17.9976(5) ?, β = 97.472(2)° and Z = 4.     

Structure of a New Bioactive Agent Containing Combined Antibacterial and Antifungal Pharmacophore Sites: 4-{[(<Emphasis Type="Italic">E</Emphasis>)-(5-Bromo-2-hydroxyphenyl)methylidene]amino}-<Emphasis Type="Italic">N</Emphasis>-(5-methyl-1,2-oxazol-3-yl)benzenesulfonamide

Abstract  

The title compound (3), C₁₇H₁₄BrN₃O₄S, is a Schiff base compound of 5-bromosalicylaldehyde (1) and sulfamethoxazole (2). The structure of (3) was determined by spectral (IR, ¹H and ¹³C NMR), elemental analyses and X-ray diffraction data. Compound (3) crystallizes in the monoclinic space group C2/c, with a = 31.936(3), b = 6.2571(5), c = 16.903(1) ?, β = 94.867(8), V = 3365.5(5) ?³, Z = 8. In the molecule of compound (3), the molecule is bent at the S atom with a C–SO₂–NH–C torsion angle of −86.3(3)°. Pairs of molecules, related by inversion centres, form intermolecular N–H···N hydrogen bonds to produce a dimer. An intramolecular phenolic O–H···N hydrogen bond is also formed. Intermolecular hydrogen bonding and π–π stacking hold the molecules together. The average distance between stacked benzene ring planes is 3.625(2) ?.     

Synthesis and Crystal Structure of a Depside Derivative 2-(2-Methoxy-2-oxoethyl)phenyl 2-(3,4-Dimethoxyphenyl)acetate

Abstract  

A depside derivative, 2-(2-methoxy-2-oxoethyl)phenyl 2-(3,4-dimethoxyphenyl)acetate (3), was synthesized through a facile approach in high yields. Its structure was confirmed by ¹H NMR, ¹³C NMR, ESI mass spectra, elemental analyses and X-ray single crystal diffraction study. Crystal structure analysis revealed that compound 3 crystallized in the monoclinic, space group P2₁/c with the following unit cell parameters: a = 10.173(2) Å, b = 10.459(2) Å, c = 16.516(3) Å, α = 90°, β = 102.30(3)°, γ = 90°, V = 1717.0(6) Å³, Z = 4.     

Structure of 2-[(Phenyl)-(3,5-Dimethyl-Pyrazol-1-yl)-Methyl]-Malonic Acid Diethyl Ester

Abstract  

The titled new functionalized ligand of type 2-[(phenyl)-(3,5-dimethyl-pyrazol-1-yl)-methyl]-malonic acid diethyl ester (4) is prepared in good yield through condensation of 3,5-dimethyl-pyrazole, with 2-arylidene-malonic acid diethyl esters 3. The structure of 4 was determined by spectral (IR, ¹H and ¹³C NMR), elemental analyses and X-ray diffraction data. The title compound (4) crystallizes in the monoclinic space group P2₁/a, with a = 7.9253 (2), b = 17.1299 (5), c = 13.4522 (4) ?, β = 90.220 (2)°, V = 1,826.25 (9) ?³, Z = 4 and with R _int = 0.021. The molecular conformation shows two possible pockets ready to coordinate two metal atoms. The crystal structure of (4) is stabilized by inter-molecular C–H⋯O and C–H⋯N hydrogen bonding.     

Crystal Structure of 4-Bromo-3,4-Dichloro-1-(1-Morpholinyl)-1-(Decylsulfanyl)-2-Nitro-Buta-1,3-Diene

Abstract  

The compound 4-bromo-3,4-dichloro-1-(1-morpholinyl)-1-(decylsulfanyl)-2-nitro-buta-1,3-diene was synthesized from the reaction of 4-bromo-1,3,4-trichloro-1-(decylsulfanyl)-2-nitro-buta-1,3-diene with morpholine and characterized by elemental analysis, IR spectrum, UV spectra, ¹H NMR,¹³C NMR and X-ray single crystal determination. In the title compound, C₁₈H₂₉BrCl₂N₂O₃S, crystallizes in the monoclinic space group P2₁/c, a = 15.8326(4) Å, b = 8.9915(10) Å, c = 16.7528(5) Å, β = 100.808(10)°, V = 2,342.6(3) Å³, Z = 4, R ₁ = 0.0590 and wR ₂ = 0.0940. The morpholine ring adopts a chair conformation. The morpholine ring and the butadiene group are inclined at an angle of 113.4 (1)°. The butadiene unit is not planar as can be expected if the two double bonds are fully conjugated.     

Synthesis,Structure, and Two Polymorphs of 4-((1,3-Dioxoisoindolin-2-yl)methyl)-1-methoxypyridinium tetrafluoroborate

Abstract  

4-((1,3-Dioxoisoindolin-2-yl)methyl)-1-methoxypyridinium tetrafluoroborate, C₁₅H₁₃BF₄N₂O₃, 1, was obtained by alkylation of the corresponding N-oxide and has been characterized by ¹H and ¹³C NMR, IR, UV spectroscopy and by X-ray crystallography. The crystal undergoes a reversible phase transition between 173 and 293 K. At room temperature, crystals are orthorhombic, space group Pna2₁ with a = 7.2487(3) ?, b = 17.8359 (8) ?, c = 12.4077(6) ?, V = 1604.16(12) ?³, and Z = 4. At 173 K, cations adopt four conformations in monoclinic space group Cc with a = 24.7076(29) ?, b = 14.4145(9) ?, c = 21.8765(25) ?, β = 126.249(17)°, V = 6283.3(7) ?³, and Z = 16. The compound is photostable in the crystal and does not undergo homolytic N–O bond cleavage as observed in solution.     

Synthesis,Characterization and Bioactivity Research of a Derivative of Secnidazole: 1-(2-Chloropropyl)-2-methyl-5-nitro-1<Emphasis Type="Italic">H</Emphasis>-imidazole

Abstract  

A secnidazole derivative, 1-(2-chloropropyl)-2-methyl-5-nitro-1H-imidazole (1), was synthesized and its single crystals were successfully grown in the mixture of ethanol/chloroform (3:1) by slow evaporation at room temperature. Its structure was confirmed by ¹H NMR, ¹³C NMR, mass spectra, elemental analyses and X-ray single crystal diffraction. Crystal structure analysis revealed that 1 crystallized in the triclinic, space group P [`1] \overline{1} with the following unit cell parameters: a = 6.5339(7) Ǻ, b = 7.5487(8) Ǻ, c = 9.7238(10) Ǻ, α = 92.894°(2), β = 96.165(2)°, γ = 102.710°(2), V = 463.78(8) ?³, Z = 2. Furthermore, this compound exhibited better anti-urease activity than secnidazole and acetyl-hydroxy acid when evaluated for antimicrobial activity against Helicobacter pylori.     

Hydrogen Bonded Triple Helical Structure of 3-Hydroxyquinoxaline-2-carboxalidine-4-aminoantipyrine

Abstract  

The title compound, C₂₀H₁₇N₅O₂·2H₂O, was synthesized by the condensation of 3-hydroxyquinoxaline-2-carboxaldehyde with 4-aminoantipyrine. The crystal structure was determined at 100 K. The molecule crystallizes in the amide tautomeric form with two molecules of lattice water in the trigonal space group P [`3] \overline{3} with a = 19.651(2) ?, c = 8.831(2) ?, Z = 6, V = 2953.3(9) ?³. Molecules assemble into a triple helix by intermolecular hydrogen bonds. The pitch distance of the helix is 26.493 ?. DFT calculations on gas phase models reveal that the iminol form of the compound is relatively stable by 3.1 kJ mol⁻¹.     

Crystal Structure and Synthesis of 17α-Acetoxy-pregn-4,6-diene-3,20-dione

Abstract  

17α-Acetoxy-pregn-4,6-diene-3,20-dione (1), C₂₃H₃₀O₄, was synthesized from the commercially available 17α-acetoxyprogesterone. X-ray diffraction analysis of (1) demonstrated that it consists of four rings, three six-membered rings (A, B and C) and one-five-membered ring (D). A, B, C and D rings occur in an envelope; half chair and chair; and half chair conformations, respectively. The crystal of 17α-acetoxy-pregn-4,6-diene-3,20-dione is in orthorhombic crystal system with space group P2₁2₁2₁, lattice constants: a = 10.843(1), b = 11.744(1), c = 15.815(2)?, V = 2013.9(4)?³, Dx = 1.222 g/cm³ and Z = 4. The molecules in the crystal are stabilized by C–H···O interactions and van der Waals forces.     

Synthesis and Crystal Structure Analysis of Substituted Diethyl Malonate

Abstract  

As intermediates of light stabilizer malonate, diethyl 3,5-di-t-butyl-4-hydroxybenzyl phenyl malonates (F.W. 454.58) was synthesized, characterized by ¹H NMR, element analysis and confirmed by X-ray crystal structure analysis. This compound crystallizes in monoclinic class under the space group P21/c with cell parameters, a = 9.8218(4) ?, b = 13.5571(5) ?, c = 19.7233(8) ?; β = 102.3530(10)°, and Z = 4. The structure exhibits inter-molecular hydrogen bonds of the type O–H–O, leading to the formation of one dimensional chains.