The Structure of a Non-Symmetric Disordered Tetramer: A Crystallographic and Solid State Multinuclear NMR Study of the Properties of 3(5)-Ethyl-5(3)-Phenyl-1H-Pyrazole

The X-ray structure and the solid-state NMR measurements, mainly ¹⁵N CPMAS of the labelled compound, allow to determine the static and dynamic properties of 3(5)-ethyl-5(3)-phenyl-1H-pyrazole. The compound is a tetramer formed by three 5-ethyl-3-phenyl-1H-pyrazole and one 3-ethyl-5-phenyl-1H-pyrazole tautomers in dynamic equilibrium with the complementary situation.     

Lithium Ion Motion in Lithium Nitridoborate Chalcogenides Li5(BN2)Ch (Ch = Se,Te)

The compounds Li₅(BN₂)Se and Li₅(BN₂)Te were synthesized at 900 °C in a closed system utilizing weld shut niobium ampoules and obtained as white microcrystalline powders. Their crystal structures were solved and refined on the basis of single‐crystal X‐ray diffraction data with the space group I4₁md [a = 6.3983(4) Å, c = 11.1072(9) Å for Li₅(BN₂)Se and a = 6.5878(3) Å, c = 11.4382(7) Å for Li₅(BN₂)Te]. The temperature dependent Li⁺ motion was investigated by ⁷Li MAS NMR spectroscopy.     

Synthesis of 3-substitued 5-(2-thienyl)isoxazoles

The reaction of 3,4,4-trichloro-1-(2-thienyl)but-3-en-1-one with hydroxylamine gave 3-hydroxyiminomethyl-5-(2-thienyl)isoxazole which was converted into 5-(2-thienyl)isoxazole-3-carbonitrile by the action of acetic anhydride in pyridine. 5-(2-Thienyl)isoxazole-3-carbonitrile reacted with hydroxylamine to produce the corresponding amide oxime. Heterocyclization of its O-acyl derivatives in acetic acid afforded 5-substituted 3-[5-(2-thienyl)isoxazol-3-yl]-1,2,4-oxadiazoles.     

Fluoroborates by Cleavage of Trimethylamine‐bis(trifluoromethyl)boranes with NEt3 × 3 HF. Structures of C6F5(CF3)2B · NMe3, K[C6H5CH2(CF3)2BF], and K[C6H5(CF3)2BF]

Trimethylamine‐bis(trifluoromethyl)boranes R(CF₃)₂B · NMe₃ (R = cis/trans‐CF₃CF=CF ( 1/2 ), HC≡C ( 3 ), H₂C=CH ( 4 ), C₂H₅ ( 5 ), C₆H₅CH₂ ( 6 ), C₆F₅ ( 7 ), C₆H₅ ( 8 )) react with NEt₃ × 3 HF depending on the nature of R at 155–200 °C under replacement of the trimethylamine ligand to form the corresponding fluoro‐bis(trifluoromethyl)borates [R(CF₃)₂BF]^– ( 1 a/2 a – 8 a ). The structures of 7 , K[C₆H₅CH₂(CF₃)₂BF] ( K‐6 a ), and K[C₆H₅(CF₃)₂BF] ( K‐8 a ) have been investigated by single‐crystal X‐ray diffraction. In 7 the CF₃ groups make short repulsive contacts with NMe₃ and C₆F₅ entities – the B–CF₃ bonds being unusually long. The B–F bond lengths of K‐6 a and K‐8 a (1.446(3) and 1.452(2) Å, respectively) are long for a fluoroborate.     

Crystal Structure and Photochromic Properties of [1-(2-Methyl-5-(4-cyanophenyl)-3-thienyl)]-2-(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene

A new photochromic diarylethene, [1-(2-methyl-5-(4-cyanophenyl)-3-thienyl-2-(2-methyl-5-phenyl-3-thienyl)]perfluorocyclopentene(1o, C28H17F6NS2), was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. Its crystal belongs to the monoclinic system, space group P21/c with a = 24.1381(5), b = 9.3834(6), c = 11.1073(8), β = 94.477(4)°, Z = 4, V = 2508.1(3) A3, D3 c = 1.445 mg/m, μ = 0.275, F(000) = 1112, the final R = 0.0482 and wR = 0.1429 for 5834 observed reflections(I 2σ(I)). Further study demonstrated the diarylethene underwent reversible photochromism, changing between colorless and blue in hexane solution, crystalline phase and PMMA films, respectively.     

Novel phosphine ligands bearing 3(5)-pyrazolyl and 4-(2-amino)pyrimidinyl groups: Synthesis and coordination chemistry

Novel triphenyl phosphine ligands bearing pyrazole or 2-aminopyrimidine groups in the ortho or meta position of one or three of the phenyl rings were obtained starting from the corresponding acyl derivatives Ph₂P(o-C₆H₄-COCH₃), Ph₂P(m-C₆H₄-COCH₃), or P(m-C₆H₄-COCH₃)₃. Conversion of the acyl groups into 3-dimethylamino-2-propen-1-onyl units was achieved by reaction with HC(OMe)₂NMe₂ which underwent ring closing with hydrazine or guanidine to yield the desired heterocycles. Two palladium complexes were synthesized using the coordinatively labile precursor (PhCN)₂PdCl₂, one of them could be characterized by X-ray structure analysis.     

Synthesis of 5-(trifluoromethyl)cyclohexane-1,3-dione and 3-amino-5-(trifluoromethyl)cyclohex-2-en-1-one: new trifluoromethyl building block

A simple synthesis of 5-(trifluoromethyl)cyclohexane-1,3-dione and 3-amino-5-(trifluoromethyl)cyclohex-2-en-1-one from the sodium salt of methyl or ethyl-4-hydroxy-2-oxo-6-(trifluoromethyl)cyclohex-3-en-1-oate is demonstrated. The compounds represent highly functionalized reactive intermediates for the synthesis of organic and heterocyclic compounds containing a trifluoromethyl group.     

Two syntheses of 5-chloro-3-(2-thienyl)-2,1-benzisoxazole

5-Chloro-3-(2-thienyl)-2,1-benzisoxazole ( 2 ) resulted from condensation of (a) o-nitrobenzaldehyde with thiophene in the presence of hydrochloric acid and (b) p-chloronitrobenzene with 2-cyanomethylthiophene. Spectral data for ( 2 ) are presented and interpreted.     

Synthese,Kristallstruktur und Festkörper-NMR-spektroskopische Untersuchungen von K5H(CN2)3

Synthesis, Crystal Structure, and Solid State MAS-NMR Spectroscopic Investigation of K₅H(CN₂)₃ Single phase K₅H(CN₂)₃ was synthesized by reaction of KHCN₂ with metallic potassium in liquid ammonia or by reaction of KNH₂ with melamine C₃N₃(NH₂)₃ at 320 °C, respectively. The crystal structure was determined from X-ray powder and single crystal data: K₅H(CN)₃, space group Im3m, a = 795.68(7) pm, Z = 2, R1 = 0.025, wR2 = 0.0438. In the solid K₅H(CN₂)₃ contains K⁺ and CN₂^2–, the anions exhibit D_∞h symmetry. According to ¹H and ¹³C solid state MAS-NMR investigations, temperature dependent impedance spectroscopy, and FTIR spectroscopy the protons are only loosely bound to the CN₂^2– ions. The proton conductivity shows a sharp increase above 70 °C.     

Studies on Vilsmeier-Haack Reaction: Application to 3-Methyl-1-Phenyl-4-Acetyl(Iminoacetyl)-2-Pyrazolin-5-One

3-Methyl-l-phenyl-4-acetyl(iminoacetyl)-2-pyrazolinones (1a,b) underwent diformylation reaction with Vilsmeier reagent to give the aminoacrolein derivatives (2a,b). The behaviour of (2a,b) towards piperidinc, morpholine, piperazine, hydroxylamine, hydrazine and phenylhydrazine has been investigated and screened in vitro for their antibacterial activities.     

2-羟基-5-甲基-5-(4-甲基戊烯-3-)基四氢呋喃的合成

本文研究了一类羰基化合物-酮类为原始料(选用了来源丰富, 价格低廉的6-甲基-5-庚烯酮-2), 经格氏反应水解, 环化及醚化即合成了2-羟基-5-(4-甲基戊烯-3-)基四氢呋喃。     

Crystal Structure and Photoreactive Properties of 1-(2,5-Dimethyl-3-thienyl)-2-[2-methyl-5-(N-(quinolin-8-yl)-2-carboxamide)-3-thienyl)]perfluorocyclopentene

The photochromic title compound,C_(26)H_(18)F_6N_2OS_2,contains a 2,5-dimethylthiophene ring and a N-formyl aminoquinolinyl thiophene ring on the C=C double bond of the cyclopentene ring.The dihedral angles between the cyclopentene and attached N-formyl aminoquinolinyl thiophene ring and 2,5-dimethylthiophene ring are 63.0° and 137.1°,respectively.The dihedral angle between the thiophene ring and the adjacent aminoquinoline ring is 5.7°.The molecule adopts an antiparallel conformation,with a distance between the two photoreactive C atoms of 3.763 ?.In addition,the absorption and fluorescence spectral changes were measured in acetonitile and solid at room temperature,and the result showed that the title compound could undergo photochromic reaction in both states.     

Synthesis of 2-trifluoromethyl-1(substituted aryl)-4(1H)-quinolones using trifluoroacetamidoyl chlorides

A simple two-step procedure for the preparation of 2-trifluoromethyl-1(substituted aryl)-4(1H)-quinolones utilizing electrophilic trifluoroacetamidoyl chlorides as the starting materials is described. The cyclization of trifluoromethyl enaminone intermediates with potassium carbonate in hot dimethylformamide produce the trifluoromethylated 4(1H)-quinolones in good to excellent yields.     

On the structural and spectroscopic properties of the thienyl chalcone derivative: 3-(5-Bromo-2-thienyl)-1-(4-nitrophenyl)-prop-2-en-1-one

In this study, we investigate the structural and spectroscopic properties of the thienyl chalcone derivative 3-(5-Bromo-2-thienyl)-1-(4-nitrophenyl)-prop-2-en-1-one, C₁₃H₈BrNO₃S, using nuclear magnetic resonance (¹H and ¹³C NMR), UV–vis and Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy at room conditions combined with density functional theory (DFT) and time-dependent DFT (TD-DFT) augmented with B3LYP/6-311G(d,p) and CAM-B3LYP/6-311G(d,p) basis sets, yielding valuable information on the molecular conformational preferences, vibrational assignments, optical properties and electronic transitions. The vibrational mode assignments of the most stable conformer of C₁₃H₈BrNO₃S are discussed based on potential energy distribution (PED) analysis and establishing a comparison with a similar chemical structure. The temperature dependence on the Raman spectra of the C₁₃H₈BrNO₃S shows a reversible phase transition in the range 443–443 K pointed out by the discontinuity in the dω/dT of bands in the external and internal modes region. The UV–vis spectrum of the C₁₃H₈BrNO₃S indicates a semiconductor behavior with an optical band gap of 2.6 eV, corresponding to the predicted value of 3.42 eV assigned as the electronic transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO). TD-DFT calculations reveal that the electron donor and acceptor group substitution on the 1-phenyl-3-(thiophen-2-yl)prop-2-en-1-one affects its absorption and nonlinear activity.     

Synthesis and Crystal Structure of 1-(2-Methyl-5-formyl-3-thienyl)-2-(2-methoxylphenyl)perfluorocyclopentene

A new family of photochromic diarylethene compounds, 1-(2-methyl-5-formyl-3- thienyl)-2-(2-methoxylphenyl)perfluorocyclopentene (1o) having an unsymmetrically substituted hexafluorocyclopentene unit, was synthesized and its structure was determined. The crystal belongs to the monoclinic system, space group P21/c with a = 15.4866(5), b = 9.0744(9), c = 12.6906(3), β = 90.1480(10)°, Z = 4, V = 1783.4(3)3, Dc = 1.513 mg/m3, μ = 0.25, F(000) = 824, the final R = 0.0579 and wR = 0.1566 for 2584 observed reflections (I > 2σ(I)). Interestingly, a colorless compound 1o undergoes photocyclization upon irradiation of UV light to give the blue isomer diarylethene. Upon irradiation with visible light with wavelength greater than 510 nm, the blue compound can return to its initial colorless state.     

Syntheses and Structural Characterization of 1-（4-Phenyl-2-thiazolyl）-3-（4-methylphenyl）-5-（2-furyl）-4,5-dihydro-（1H）-pyrazole and 1-（4-（4-Fluoro）phenyl-2-thiazolyl）-3-（4-methyl-phenyl）-5-（2-furyl）-4,5-dihydro-（1H）-pyrazole

The title compounds were synthesized and characterized by IR,1H-NMR,Mass and elementary analysis and single-crystal X-ray diffraction.In 1a,intermolecular C-H…π interactions produce a three-dimensional network.In 1b,intermolecular C-H…O hydrogen bonds generate an R22(22) ring.The hydrogen bonding is supported by C-H…π interactions.     

Methyl 2-methoxytetrafluoropropionate as a synthetic equivalent of methyl trifluoropyruvate in the Claisen condensation. The first synthesis of 2-(trifluoroacetyl)chromones and 5-aryl-2-hydroxy-2-(trifluoromethyl)furan-3(2H)-ones

2-(Trifluoroacetyl)chromones and 5-aryl-2-hydroxy-2-(trifluoromethyl)furan-3(2H)-ones were obtained in good yields via the Claisen condensation of acetophenones with methyl 2-methoxytetrafluoropropionate, followed by sulfuric acid-mediated deprotection of the reaction products.