Molecular structure and vibrational assignment of melaminium phthalate by density functional theory (DFT) and ab initio Hartree-Fock (HF) calculations

The molecular geometry, the normal mode frequencies and corresponding vibrational assignment of melaminium phthalate (C₃H₇N₆⁺·C₈H₅O₄⁻) in the ground state were performed by HF and B3LYP levels of theory using the 6-31G(d) basis set. The optimized bond length numbers with bond angles are in good agreement with the X-ray data. The vibrational spectra of melaminium phthalate which is calculated by HF and B3LYP methods, reproduces vibrational wave numbers with an accuracy which allows reliable vibrational assignments. The title compound has been studied in the 4000–100 cm⁻¹ region where the theoretical evaluation and assignment of all observed bands were made.     

The molecular structure and vibrational spectra of 2-chloro-N-(diethylcarbamothioyl)benzamide by Hartree-Fock and density functional methods

2-Chloro-N-(diethylcarbamothioyl)benzamide (C(12)H(15)ClN(2)OS) has been synthesized and characterized by elemental analysis and IR spectroscopy. The crystal and molecular structure of the title compound has been determined from single crystal X-ray diffraction data. It crystallizes in the orthorhombic space group Pbca, Z=8 with a=9.581(3)A, b=9.992(3)A, c=26.640(8)A, V=2550.5(13)A(3) and D(calc)=1.410 Mg/m(3). The molecular geometry and vibrational frequencies of 2-chloro-N-(diethylcarbamothioyl)benzamide in the ground state have been calculated using the Hartree-Fock and density functional using Becke's three-parameter hybrid method with the Lee, Yang and Parr correlation functional (B3LYP) methods with 3-21G and 6-31G(d) basis sets. The calculated geometric parameters were compared to the corresponding X-ray structure of the title compound. The raw B3LYP frequencies approximate the experimental data much better than the results of Hartree-Fock. The scaled B3LYP/6-31G(d) results were more reliable than those obtained using the B3LYP/3-21G method with the mean absolute deviation about 13.7 cm(-1). On the basis of the comparison between calculated and experimental results, assignments of fundamental vibrational modes were examined.     

1,5-Dimethy-4-[(3-nitro-benzylidene)-amino]-2-pheyl-1,2-dihydro-pyrazol-3-one

1INTRODUCTION Antipyrine(2,3-dimethyl-1-phenyl-5-pyrazolone)and its derivatives exhibit a wide range of biological activities and applications[1~3].Antipyrine shows mi-nimal protein binding and is rapidly and completely absorbed from the gastrointestinal tract and exten-sively metabolized by the cytochrome P450liver en-zymes[4].Estimates of half-life and systemic cleara-nce of antipyrine have been used for the in vivo asse-ssment of hepatic drug oxidation in different spe-cies[5].Owing to…     

4-[（Furan-2-ylmethylene）-amino]-1,5- dimethyl-1,2-dihyl-1,2-dihydo-pyrazol-3-one

1 INTRODUCTION Antipyrine (2,3-dimethyl-1-phenyl-5-pyrazolone) and its derivatives exhibit a wide range of biological activities and applications[1～3]. Antipyrine shows mi- nimal protein binding and is rapidly and complete- ly absorbed from the gastrointestinal tract and exten- sively metabolized by the cytochrome P450 liver en- zymes[4]. Estimates of half-life and systemic clear- ance of antipyrine have been used for the in vivo as- sessment of hepatic drug oxidation in different spe- c…     

4H-吡啶并[3,2-e][1,3]噻嗪-4-酮嘧啶衍生物的合成

2-氯烟酸异硫氰酸酯在碱性介质中与取代2-氨基嘧啶反应直接得到4H-吡啶并[3,2-e][1,3]噻嗪-4-酮嘧啶. 所合成的6个未见文献报道的目标化合物经IR, ¹H NMR和元素分析证实了其结构, 并对反应可能机理进行了探讨.     

Reaction of 6-methoxybenzo[b]furan-3(2H)-one and benzo[b]thiophen-3(2H)-one with 2-aryl-1,1-dicyanoethylenes as a convenient synthetic route to substituted 2-amino-4-aryl-1,3-dicyano-7-methoxydibenzo[b,d]furans and 2-amino-4-aryl-3-cyano-4H-benzothieno[3,2-b]pyrans

The reactions of 6-methoxybenzo[b]furan-3(2H)-one with 2-aryl-1,1-dicyanoethylenes and malononitrile or with aromatic aldehyde and two moles of malononitrile afford 2-amino-4-aryl-1,3-dicyano-7-methoxydibenzo[b,d]furans. The reactions of benzo[b]thiophen-3(2H)-one with 2-aryl-1,1-dicyanoethylenes or with aromatic aldehyde and one mole of malononitrile produce 2-amino-4-aryl-3-cyano-4H-benzothieno[3,2-b]pyrans.     

Synthesis and Crystal Structure of 1-（4-Fluorophenyl）-2-hexylthiobenzo[4,5]-furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5（1H）-one

The crystal structure of the title compound 1-(4-fluorophenyl) -2-hexylthio-benzo [4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5(1H) -one(C23H21FN4O2S,Mr = 436.5) has been prepared and determined by single-crystal X-ray diffraction. The crystal is of monoclinic,space group P21/n with a = 13.9854(3) ,b = 17.2678(4) ,c = 18.1828(5) ,β = 99.364(2) °,V = 4332.58(18) 3,Z = 4,Dc = 1.338,F(000) =1824,μ = 0.185 mm-1,MoKa radiation(λ = 0.71073) ,R = 0.0538 and wR = 0.1162 for 4728 observed reflections with I > 2σ(I) . X-ray diffraction analysis reveals the fused rings of benzo[4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a] pyrimidin-5(1H) -one system are nearly coplanar. The crystal packing is mainly stabilized by weak intermolecular C-H···O hydrogen bond and π-π interactions.     

Synthesis and Crystal Structure of 2-(4''-Methylphenoxy)-5,8,9-trimethyl-3-phenyl Thieno[3'',2'':5,6]pyrido[4,3-d]pyrimidin-4-(3H)-one Hydrochloride

The title compound 2-(4′-methylphenoxy)-5,8,9-trimethyl-3-phenyl thieno[3′,2′:5,6]pyrido[4,3-d]pyrimidin-4(3H)-one hydrochloride (C26H23Cl4N3O2S, Mr = 583.33) has been deter- mined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c with a = 14.8442(11), b = 11.5131(8), c = 17.2010(13) (A), β = 113.7250(10)o, V = 2691.3(3) (A)3, Z = 4, Dc = 1.440 g/cm3, S = 1.094, μ = 0.547 mm-1, F(000) = 1200, the final R = 0.0571 and wR = 0.1458. X-ray analysis reveals that the title compound combines with a molecule of dichloromethane by an intramolecular hydrogen bond. The thienopyridine ring is almost coplanar, and the dihedral angle between the thiophene plane and the pyridine plane is 0.6o.     

Heteroannulated Quinazoline and Quinazolinone Derivatives from (Z)-2-[1-Benzamido-2-(3,4,5-trimethoxyphenyl)]vinyl-3,1-benzoxazin-4(3H)-one

The title compound 1 was prepared and allowed to react with a series of nitrogen nucleophiles to afford the quinazoline and quinazolinone derivatives 2–12 and tetrazole derivative 13. The IR, ¹H NMR, ¹³C NMR, and mass spectra of all the synthesized compounds were discussed.     

Synthesis and Crystal Structure of 2-Ethoxy-3-n-butyl-benzofuro[2,3-d]pyrimidin-4（3H）-one

The crystal structure of the new title compound 2-ethoxy-3-n-butyl- benzofuro[2,3d]pyrimidin-4（3H）-one （C16H18N2O3, Mr = 286.32） has been prepared and determined by singlecrystal X-ray diffraction. The crystal is of monoclinic, space group P21/c with a = 13.7167（14）, b = 13.113（1）, c = 8.378（1） A, β = 98.992（2）^o, V = 1488.4（3） A^3, Z = 4, Dc = 1.278, F（000） = 608, μ = 0.089 mm^-1, MoKa radiation （2 = 0.71073）, R = 0.0498, wR = 0.1238 for 2336 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that all ring atoms in the benzo[4, 5]furo [2,3-d] pyrimi- dinone moieties are almost coplanar.     

Theoretical and experimental study of molecular structure and vibrational spectra of <Emphasis Type="Italic">N</Emphasis>-(2-pyridylmethyl)-2-pyrazinecarboxamide

N-(2-Pyridylmethyl)-2-pyrazinecarboxamide was prepared and its crystal structure was investigated by X-ray analysis. The compound crystallizes in the triclinic space group \(P{\bar 1}\) with a = 4.262(3), b = 12.117(9), c = 20.840(18) Å, α = 91.802(6), β = 89.834(7), γ = 91.845(6)°, V = 1075.2(16) ų, Z = 4, and D = 1.323?Mg/m³. The structure was solved by direct method and refined to R = 0.0699 and wR ₂ = 0.1268 by full matrix anisotropic least-squares method. Using the Hartree-Fock and density functional method (B3LYP) with 6-31G(d) basis set, the molecular geometry and vibrational frequencies of the title compound has been investigated and compared with experimental ones from experimental studies. The optimized bond lengths obtained by RHF method and bond angles obtained by B3LYP method show better agreement with the experimental values. The vibrations computed of the title compound by the RHF and DFT methods are in good agreement with the observed IR spectra data.     

4,5-二[2-(邻甲酰苯氧基)乙硫基]-1,3-二硫环戊烯-2-酮的合成及晶体结构

以水杨醛与1,2-二溴乙烷为反应物, 乙腈为溶剂, 在无水K₂CO₃存在下合成了2-溴乙氧基水杨醛(1), 1和二-(1,3-二硫杂环戊烯-2-硫酮-4,5-二硫)合锌酸四乙基铵盐在乙腈中回流, 得到新型的四硫富瓦烯(TTF)前体(2). 在Hg(OAc)₂存在下, 2可转化为4,5-二[2-(邻甲酰苯氧基)乙硫基]-1,3-二硫环戊烯-2-酮(3), 其结构经¹H NMR, FT-IR, 元素分析和单晶X射线衍射分析得到确证.     

The Reaction of 4-Formylsydnone and Methyl Ketones

In the presence of base, 3-subslituted 4-fonnyl- and 4-acetylsydnones decarbonylated to afford the corresponding 3-substituted sydnones. The Claisen-Schmidt reaction occurred between 3-substituted 4-for-mylsydnones and methyl ketone (such as 4-acetylsydnones, acetone and acetophenone) in dilute basic solution or electrogenerated basic (EGB) solution.     

Enantioselective syntheses of no-carrier-added (n.c.a.) (s)-4-chloro-2-[f] fluorophenylalanine and (s)-(α-methyl) -4-chloro-2-[f]fluorophenylalanine

(S)-4-Chloro-2-fluorophenylalanine and (S)-(α-methy)-4-chloro-2-fluorophenylalanine were synthesized and labeled with no carrier added (n.c.a.) fluorine-18 through a radiochemical synthesis relying on the highly enantioselective reaction between 4-chloro-2-[¹⁸F]fluorobenzyl iodide and the lithium enolate of (2S)-1-(tert-butyloxycarbonyl)-2-(tert-butyl)-3-methyl-1,3-imidazolidine-4-one for (S)-4-chloro-2-[¹⁸F]fluorophenylalanine and (2S,5S)-1-(tert-butyloxycarbonyl)-2-(tert-butyl)-3,5-dimethyl-1,3-imidazolidine-4-one for (S)-(α-methyl) -4-chloro-2-[¹⁸F] fluorophenylalanine. Quantities of about 20–25 mCi were obtained at the end of sy nthesi s, ready for injection after hydrolysis and high performance liquid chromatography (HPLC) purification, with a radiochemical yield of 17%–20% corrected to the end of bombardment after a total synthesis time of 90–105 min from [¹⁸F] fluoride. The enantiomeric excesses were shown to be 97% or more for both molecules without chiral separation and the radiochemical and chemical purities were 98% or better.     

A study of the Claisen rearrangement of 7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one derivatives

Summary The Claisen rearrangement of 7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one (2 a) gave 7-hydroxy-8-(1-phenyl-2-propenyl)-3-phenyl-(4H)-1-benzopyran-4-one (3 a) and 2,3-dihydro-2,6-diphenyl-3-methyl-(7H)furo[2,3-h]-1-benzopyran-7-one (7 a). 2-Methyl-7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one (2 b) afforded4 b and7 b. 8-Methyl-7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one (12) gave only the alkali soluble product 7-hydroxy-8-methyl-6-(1-phenyl-2-propenyl)-3-phenyl-(4H)-1-benzopyran-4-one (13).3 a,4 b, and13 were further cyclized in acidic medium to9 a,10 b, and14 followed by dehydrogenation.This paper is dedicated to Dr. F. M. Dean, Department of Organic Chemistry, Robert Robinson Laboratories, University of Liverpool, Liverpool, U. K., on his retirement     

Synthesis and Structure of 6-(4- Fluorobenzylamino)-3-methylthio-1,5- diphenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one

1 INTRODUCTION It was reported that the pyrazolopyrimidinone derivatives play a very important role in the bio- chemistry of living cell. Many potential drugs[1～3] and agrochemicals[4, 5] have been modeled on the compound, and the study on derivatives …     

Synthesis and Crystal Structure of 3-（4-Chlorophenyl）-8-cyano-2-（di-isopropylamino）-5-methyl-7-（methylthio）-pyrido[4,3-d]pyrimidine-4（3H）-one

The crystal structure of the new title compound 3-(4-chlorophenyl)-8-cyano-2-(di-iso-propylamino)-5-methyl-7-(methylthio)-pyrido[4,3-d]pyrimidine-4(3H)-one(C22H24ClN5OS,Mr = 441.97)has been determined by single-crystal X-ray diffraction. The crystal is of orthorhombic,space group Pna21 with a = 7.6721(5),b = 18.9370(11),c = 15.6260(9),V = 2270.2(2)3,Z = 4,Dc = 1.293 g/cm3,F(000)= 928,μ = 0.283 mm-1,MoKa radiation(λ = 0.71073 ),R = 0.0494 and wR = 0.1062 for 3278 observed reflections with I > 2σ(I). X-ray diffraction analysis reveals that all ring atoms in the py-ridopyrimidinone moiety are almost coplanar. Intramolecular C(20)-H(20)···N(4),C(19)-H(19A)···N(3),C(18)-H(18C)···N(3)and C(16)-H(16B)···O(5)hydrogen bonds together with weak C···π interactions are found in the structure.     

An experimental and theoretical study of molecular structure and vibrational spectra of 2-chloronicotinic acid by density functional theory and ab initio Hartree–Fock calculations

In this work, the Fourier transform Raman and Fourier transform infrared spectra of 2-chloronicotinic acid (2-CNA) are recorded in the solid phase. The molecular geometry, vibrational frequencies, infrared intensities and Raman scattering activities of 2-CNA in ground state have been calculated by using ab initio Hartree–Fock (HF) and density functional (B3LYP and B3PW91) methods with 6-31G(d) and 6-311G(d) basis sets level. On the basis of the comparison between calculated and experimental results and the comparison with related molecule, assignments of fundamental vibrational modes are examined. The optimized geometric parameters (bond lengths and bond angles) obtained by using HF show the best agreement with the experimental values of 2-CNA. Comparison of the observed fundamental vibrational frequencies of 2-CNA and calculated results by density functional (B3LYP and B3PW91) and Hartree–Fock methods indicates that B3LYP is superior to the scaled Hartree–Fock and B3PW91 approach for molecular vibrational problems.     

Deoxypegan-1-one derivatives. synthesis and borohydride reduction of 3-[(E)-arylmethylidene]-3,9-dihydropyrrolo[2,1-b]quinazolin-1(2H)-ones

3-[(E)-Arylmethylidene]-3,9-dihydropyrrolo[2,1-b]quinazolin-1(2H)-ones were prepared by reaction of quinazolyl-2-propionic acid hydrochloride with aromatic aldehydes in acetic anhydride in the presence of Et₃N. 3-[(E)-Arylmethylidene]-1,2,3,9-tetrahydropyrrolo[2,1-b]quinazolin-1-ols were formed by reduction of the 3-arylidene derivatives with sodium borohydride in methanol, readily lost water when heated with acids, and were converted into 3-[(E)-arylmethylidene]-3,9-dihydropyrrolo[2,1-b]quinazolines. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 463–467, September–October, 2006.     

2-[4-(Dimethylamino)phenyl]-3-hydroxy-4H-chromene-4-one: A H-bond-sensitive fluorescent probe for investigating binary mixtures of organic solvents

Molecules of electronically excited 2-[4-(dimethylamino)phenyl]-3-hydroxy-4H-chromene-4-one (a fluorescent probe) co-exist in the normal (N^*) and tautomeric (T^*) forms and emit radiation in different spectral regions. The positions (expressed in wave numbers, ν) and intensities (I) of the emission bands are strongly affected by the ability of the medium's molecules to participate in hydrogen bonding with the probe. In such cases, I_N*, I_N*/I_T*, ν_N*, ν_N* + ν_T* or ν_N* − ν_T*, depend on the concentration (over a certain range) or its base-10 logarithm (log) of the component interacting with the probe. These relationships form the basis for a quantitative assay of such compounds in binary mixtures. On the other hand, the log(I_N*/I_T*) versus ν_N* + ν_T* or ν_N* − ν_T* relationships demonstrate unique features that can be used to distinguish components (alcohols) interacting with the probe and to quantify their contents. The prospects for the analytical application of these findings are outlined briefly.