Studies on the crystal structure and characterization of N-(4-acetylphenyl)-N’-(2-nitrobenzoyl)-thiourea

N-(4-acetylphenyl)-N′-(2-nitrobenzoyl)-thiourea has been synthesized in high yield under PEG-400 as the phase-transfer catalyst and its the compound structure was determined by single crystal X-ray diffraction. The compound is also a considerable plant-growth regulator. In addition, the compound L exhibited selective recognition for Hg²⁺ over other metals ions such as Ag⁺, Ca²⁺, Co²⁺, Ni²⁺, Cd²⁺, Pb²⁺, Zn²⁺, Cr³⁺, and Mg²⁺ in DMSO solutions.     

Synthesis,Characterization and X-ray Structure of N-(4-bromobutanoyl-N’-(2-3- and 4-methylphenyl)thiourea

N-4-(bromobutanoyl)-N'-(o-, m- and p-tolyl)thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR, and NMR spectroscopic techniques. The two carbonoylthiourea isomers N-(4-bromobutanoyl)-N'-(3-methylphenyl)thiourea(3b) and N-(4-bromobutanoyl)-N'-(4-methylphenyl)thiourea(3c) were obtained in crystalline form by recrystallization from DMSO. Xray crystallographic studies showed that both compounds 3b and 3c crystallize in triclinic system with space group of P1. The molecules adopt trans-cis configuration with respect to the positions of 4-bromobutanoyl and tolyl groups respectively, against the thiono C=S bond across their C–N bonds. The configuration is attributed by the intrahydrogen bond between the carbonyl oxygen and amide hydrogen atoms. Both crystal structures are stabilized by N–H···S intermolecular hydrogen bonds to form dimers and arranged along the b axis.     

Structures and NMR spectra of N-(ω-alkoxyethyl)N-(2-hydroxyethyl)-N,N-dimethylammonium chlorides

Russian Chemical Bulletin - Homoand heteronuclear NMR experiments (COSY, HSQC, and HMBC) were used for the attribution of the proton and carbon atom signals in the 1H and 13C NMR spectra of...     

Vibrational spectra of N-2′-methyl-propyliden-propan-2-amine: conformational analysis and influence of the nitrogen hybridization

Infrared and Raman spectra of the (CH₃)₂C^2′HC^1′HNCH(CH₃)₂ aldimine (NPP) and of two deuterated derivatives at C^1′ and C^2′ in the liquid, solid and solution phases have been recorded and assigned between 4000 and 130 cm⁻¹. NPP adopts the E configuration and two conformers at the C_sp2 and N sides are in equilibrium. Some vibrational modes are specifically assigned to the anticlinal (ac) or synperiplanar (sp) conformers at the C_sp2 side. The ac(C_sp2) form is dominant in the pure liquid whilst the sp(C_sp2) form is favoured in the solid and in chloroform. The vibrational dynamics of the isopropyl group on both sides of the CN bond are partially similar to that of the (CH₃)₂CHCHO aldehyde on the one hand and of the (CH₃)₂CHNH₂ amine on the other hand. When moving from the amine to the corresponding aldimine, changes about νNC and wCC₂ modes (at the N side) are related to electronic and geometrical effects as a consequence of the nitrogen hybridization change from sp₃ to sp₂.     

Synthesis and Crystal Structure of 1,4-Bis(2-hydroxymethylphenyl)-1,4-dioxabutane

1 INTRODUCTION Macrocyclic ligands and their metal complexes have received much attention due to their applications in ion transport, ion separation and as models in biomimic researches[1~7]. The synthetic methods of macrocyclic ligands and their metal complexes are mainly divided into three kinds[8]. The first one is synthesizing free ligand, then forming the metal complexes; the second is template synthesis; and the third is synthesizing the end-off or side-off precursor ligand, then c…     

Synthesis and Chiroptical Properties of Poly[N-(4-N′-(α-Methylbenzyl)-Aminocarbonylphenyl)-Mamaleimide]

Abstract

Radical homopolymerization of N-[4-N′-(α-methylbenzyl)-aminocarbonylphenyl]maleimide ((S)-MBCP) was carried out at 50 and 70°C for 24 h to give optically active polymers ([α]²⁵ _D = 159.8 to 163.4°). Radical copolymerizations of (S)-MBCP (M₁) were performed with styrene (ST, M₂, methyl methacrylate (MMA, M²) in THF at 50°C. The monomer reactivity ratios (r ₁, r ₂) and the Alfrey-Price Q, e values were determined as follows: r ₁ = 0.32, r ₂= 0.14, Q ₁ = 1.74, e ₁ = 0.96 in the (S)-MBCP-ST system; r ₁ = 0.54, r ₂ = 0.93, Q ₁ = 1.11, e ₁ = 1.23 in the (S)-MBCP-MMA system. Chiroptical properties of the polymers and the copolymers were also investigated, and asymmetric induction into the copolymer main chain is discussed.     

Ab initio calculations of the structural and elastic properties of CoSi2

Under GGA, the geometry, energy, electronic structure, and elastic properties of the CoSi₂ have been investigated by using ab initio plane-wave ultrasoft pseudopotential method. The calculated equilibrium lattice parameter a and elastic stiffness constants c ₁₁, c ₁₂, and c ₄₄ are in better agreement with the experimental values than those obtained by both the VAMP and FLAPW with LDA. For engineering and technological applications, the isotropic elastic properties, including the shear modulus G, the bulk modulus B, Young’s modulus E, and Poisson’s ratio , are also calculated for polycrystalline CoSi₂ with Voigt, Reuss, and Hill approximations. The lower Poisson’s ratio of 0.327 means an increase in the volume is associated with the uniaxial tensile deformation and the higher ratio of bulk modulus to shear modulus B/G of 2.56 indicates the ductility of CoSi₂ which is in accordance with the metallic property of CoSi₂ obtained by the density of states.     

The molecular and crystal structure of N-(4-n-butyloxybenzylidene)-4′-ethylaniline (4O.2) and N-(4-n-heptyloxybenzylidene)-4′-hexylaniline (7O.6)

Abstract

The molecular and crystal structure of N-(4-n-butyloxybenzylidene)-4′-ethylaniline (4O.2) and the homologue N-(4-n-heptyloxybenzylidene)-4′-hexylaniline (7O.6) have been solved (at room temperature) by direct methods. The crystals of both compounds belong to the triclinic system with space group P1 with two molecules per unit cell. 4O.2: a = 5·531(2), b = 7·592(3), c = 19·746(7) Å, α = 86·66(2), β = 88·15(2), γ = 90·29(2)° 7O.6: a = 5·420(2), b = 8·307(3), c = 28·057(7) Å, α = 91·69(2), β = 89·76(2), γ = 108·02(2)°. The structures were refined by full-matrix least-squares calculations to R = 0·036 for 2297 observed reflections for 4O.2 and to R = 0·037 for 2150 reflections for 7O.6. The conformations in the asymmetric units of the two compounds differ considerably: The planes of the two phenyl rings of 4O.2, forming the mesogenic core of the molecule, are twisted at 61·2° to each other and the butoxy group contains a gauche conformation. In contrast the heptoxy chain of 7O.6 forms an all trans-conformation which lies almost in one plane with the two coplanar phenyl rings. The hexyl group also exists in an extended form, in a plane which is rotated against the plane of the mesogenic unit. The packing in the crystalline state of the two homologues exhibits a layered structure along c*; in 4O.2 these layers are separated, but in 7O.6 they are interdigitated. The compensation of the dipole moments of the C?O?C and C?N?C bonds occurs similarly in both structures: molecular orientations parallel to the a, c-plane in which the long axes of the molecules points in the same direction are packed in antiparallel fashion along b*.     

Syntheses of Methyl 2-O-, 3-O- and 6-O-(2′-Hydroxypropyl)-α-D-Glucopyranosides 1

Abstract

Methyl 6-O-, 3-O- and 2-O-(2′-hydroxypropyl)-α-D-glucopyranosides (4,8, and 12) were synthesized starting from methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (1), methyl 4,6-O-benzylidene-α-D-glucopyranoside (5), and methyl 3-O-benzyl-4,6-O-benzylidene-D-glucopyranoside (9), respectively. Overall yields were 88%, 6% and 26% of 4, 8 and 12, respectively, with the 2-ether (12) being crystalline and the 3-ether (8) a single diastereomer.

     

Synthesis and cyclization of N-(2-hydroxyphenyl)-and N-(2-benzyloxyphenyl)-Β-alanines

N-Substituted -alanines have been synthesized by treating o-aminophenol or o-benzyloxyaniline with acrylic, methacrylic, or crotonic acids. Their cyclization to 2-benzoxazolinones and dihydro-2,4(1H,3H)-pyrimidinediones has been studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 527–531, April, 1991.     

Synthesis and Cyclization of N-(4-Phenoxyphenyl)-β-alanines

We have used the reaction of 4-aminodiphenyl ester with acrylic, methacrylic, crotonic, and itaconic acids to synthesize N-substituted -alanines, which undergo ring closure to form derivatives of dihydropyrimidinedione and 4-carboxy-2-pyrrolidinone. We have studied the reactions of acylation and recyclization of the dihydropyrimidinedione ring, and we have synthesized derivatives of 4-carboxy-1-(4-phenoxyphenyl)-2-pyrrolidinone: arylidene hydrazides, 2[(2-oxo-4-pyrrolidinyl-1-(4-phenoxyphenyl)]benzimidazole.     

Synthesis and mesomorphic properties of 4-(4-bromopropyloxy)-4’-(4-alkyloxybenzylidene)anilines

This article describes the preparation and liquid crystalline properties of a new homologous series of 4-（4-bromopropyloxy）-4’- （4-alkyloxybenzylidene）anilines in which the phenyl ring is armed by a bromopropyloxy chain.The thermal behavior and mesomorphic properties of the synthesized compounds were studied with particular attention given to the correlation between their phase transition temperatures and anisotropic change influenced by molecular structure.All the members displayed enantiotropic smectic phase except for the homologue with the longest alkyloxy chain(R = C₁₈H₃₇),exhibiting only monotropic characteristic. The presence of bromine atom from the propyloxy side chain is found to be capable of altering and influencing the mesomorphic properties.     

4-溴-N,N-二(2-氨基苯氧乙基)苯胺的合成

以对溴苯胺为原料,经4步反应合成了4-溴-N,N-二(2-氨基苯氧乙基)苯胺,其结构经1H NMR, IR和MS表征.     

Synthesis and Characterization of N-(2,2-Diphenylacetyl)- N′-Substituted Thiourea Derivatives: The Crystal Structure of N-(2,2-Diphenylacetyl)-N′-(4-chloro phenyl)-thiourea

A series of new N-(2,2-diphenylacetyl)-N ′-substituted thiourea derivatives (1–9) have been prepared and characterized by elemental analyses, IR and ¹H NMR spectroscopy. N-(2,2-diphenylacetyl)-N ′-(4-chlorophenyl)-thiourea was also characterized by a single crystal X-ray diffraction study. The compound crystallizes in the monoclinic space group P2₁/c with Z = 4 and a = 9.6551(19) Å, b = 20.060(4) Å, c = 9.894(2) Å, β = 104.29(3)°. The molecular conformation of the compound is stabilized by an intramolecular (N1-H1···O1) hydrogen bond that forms a pseudo-six-membered ring.     

Synthetic Mucin Fragments: Methyl-3-O-(2-Acetamido-2-Deoxy-4-O- and 6-O-β-D-Galactopyranosyl-β-D-Glucopyranosyl)-β-D-Galactopyranoside and Methyl 3-O-(2-Acetamido-2-Deoxy-4-O- and 3-O-Methyl-β-D-Glucopyranosyl-3-D-Galactopyranoside

Abstract

Glycosylation of methyl 3-O-(2-acetamido-3, 6-di-O-benzyl-2-deoxy-β-D-glucopyranosyl)-2,4,6-tri-O-benzyl-β-D-galactopyranoside (2) with 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide (1), catalyzed by mercuric cyanide, afforded a trisaccharide derivative, which was not separated, but directly O-deacetylated to give methyl 3-O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-β-D-galactopyranosyl-β-D-giucopyranosyl)-2,4,6-tri-O-benzyl-β-D-galactopyranoside (8). Hydrogenolysls of the benzyl groups of 8 then furnished the title trisaccharide (9). A similar pflyccsylation of methyl 3-O-(2-acetamido-3-O-acetyl-2-deoxy-β-D-glucopyranosyl)-2,4,6-tri-O-benzyl- β-D-galactopyranoside (obtained by acetylation of 4, followed by hydrolysis of the benzylidene acetal group) with bromide 1 gave a tribenzyl trisaccharide, which, on catalytic hydrogenolysls, furnished the isomeric trisaccharide (12). Methylation of 4 and 2 with methyl iodide-silver oxide in 1:1 dichloro-methane-N, N-dimethylformamide gave the 3-O- and 4-O-monomethyl ethers (13) and (15), respectively. Hydrogenolysis of the benzyl groups of 13 and 15 then provided the title monomethylated disaechartdes (15) and (16), respectively. The structures of trisacchacides 9 and 12, and disaccharides 14 and 16 were all established by ¹³C MMR spectroscopy.     

Kinetics and mechanism of mercuration of N-(substituted benzylidene)-4-toluidines

In order to investigate the mechanism of mercuration reaction of substituted ben-zylideneanilines, kinetic measurements of these reactions at different temperatures (40-60℃) inmethanol-l,4-dioxane (1/1, V/V) were carried out and Hammett ρ value for C-phenyl substituentsof-0.61 for the N-(substituted benzylidene)-4-toluidine series was obtained. Thermodynamicparameters E_a, △S~≠ were obtained for the reaction of different. N-(substituted benzylidene)-4-toluidines. It was found that this ortho-mercuration was brought about by an internal cyclometal-lation process involving the imino-moiety.     

Synthesis, Dimeric Crystal Structure, and Biological Activities of N-(4-Methyl-6-oxo-1,6-dihydro-pyrimidin-2-yl)-N′-(2-trifluoromethyl-phenyl)-guanidine

IntroductionPlants have a more extensive biosynthetic capacitythan animals, which is attributed to the fact that ani-mals rely on their diet for the supply of many biochemi-cal compounds and their precursors. Owing to thisdifference, plants contain numero…     

Ab initio quantum mechanical calculations of energy,geometry, vibrational frequencies and IR intensities of tetraphosphorus tetrasulphide, α-P4S4(D2d), and vibrational analysis of As4S4 and As4Se4

Geometry, vibrational frequencies and IR intensities are calculated for α-P₄S₄ by scaled quantum mechanical calculations at the 6-31G*/SCF and STO-3G*/SCF levels. For both basis sets the frequencies are scaled with factors close to or equal to those found for P₄S₃, and based on these results a revised assignment is proposed. The α-P₄S₄ force field is transferred to the isostructural As₄S₄ and As₄Se₄ molecules and rescaled, and based on a good fit to experimental frequencies a new assignment is also proposed for these compounds.     

Temperature-dependent Raman study of pure and silver nanoparticles dispersed N-(4-n-heptyloxybenzylidene)-4’-n-butylaniline (7O.4)

Temperature-dependent micro-Raman study of C-H in-plane bending mode of aromatic rings, C-N and C=N stretching of linking group (-C(H)=N) and C=C stretching of rings of pure and silver nanoparticles dispersed (0.5% and 1% by weight) Schiff’s base liquid crystal (LC) compound, N-(4-n-heptyloxybenzylidene)-4’-n-butylaniline (7O.4) in 500–2250 cm^?1 region has been done. The change in Raman spectral parameters (peak position and linewidth) at crystal–smecticG (K–smG) and smecticG–smecticC (smG–smC) gives the evidence of charge shift at phase transition which is associated with changes in orientation and vibrational freedom of the molecules. The peak position of the Raman bands shows blue shift for 0.5 wt% dispersed sample, whereas it shows red shift for 1 wt% dispersed sample. The blue and red shifts of the Raman bands indicate an increase and decrease in the charge density, respectively. The optimised structure and theoretical room temperature Raman spectra of 7O.4 were obtained using density functional theory. The vibrational assignment using potential energy distribution is reported using vibrational energy distribution analysis (VEDA).     

1,4-双(4′-N,N-二甲基氨基苯乙烯基)萘的合成及荧光性质

利用Wittig反应合成了一个以萘为π-Center的对称型“D-π-D”有机绿色发光化合物1,4 双(4′-N,N-二甲基氨基苯乙烯基)萘(BDASN),并测试了其在不同环境中的光谱性质.在378nm激发波长的激发下,BDASN显示出很强的荧光发射峰,峰位在521nm(CH₂Cl₂).随着溶剂极性增大,最大发射波长红移且荧光强度降低,与“D-π-A”分子具有相似的分子内电荷转移(TICT)行为.在β-环糊精(β-CD)中BDASN的绿色发光带被猝灭,同时在450nm附近蓝发光带的荧光强度骤增.