Synthesis and rearrangement of 4-imino-4H-3,1-benzoxazines

Summary N-Acylanthranilamides react with dibromotriphenylphosphorane in the presence of triethylamine as HBr captor to give 4-imino-4H-3,1-benzoxazines in good yields. If the reaction is carried out without acid acceptor, N-acetylanthranilamides yield 2-methyl-4-quinazolones, whereas N-benzoylanthranilamides give 2-phenyl-4-imino-4H-3,1-benzoxazines. It has also been found that 2-methyl-4-imino-4H-3,1-benzoxazines rearrange under the influence of HCl or HBr into the respective 2-methyl-4-quinazolones; 2-phenyl-4-imino-4H-3,1-benzoxazines, however, do not undergo such a rearrangement.

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Synthese und Umlagerung von 4-Imino-4H-3,1-benzoxazinen

Zusammenfassung Die Umsetzung von N-Acyl-anthranilsäure-amiden mit Triphenyldibromphosphoran in Gegenwart von Triethylamin als HBr-Akzeptor führt mit guten Ausbeuten zu 4-Imino-4H-3,1-benzoxazinen. Wird die Reaktion ohne säurebindendes Mittel durchgeführt, dann entstehen aus N-Acetyl-anthranilsäure-amiden 2-Methylchinazolone-4, jedoch erhält man aus N-Benzoylanthranilsäure-amiden 2-Phenyl-4-imino-4H-3,1-benzoxazine. 2-Methyl-4-imino-4H-3,1-benzoxazine erleiden unter dem Einfluß von HBr oder HCl eine Umlagerung in entsprechende 2-Methylchinazolone-4, während 2-Phenyl-4-imino-4H-3,1-benzoxazine zu einer solchen Umlagerung nicht befähigt sind.

     

The Synthesis of Functionalised Diaryltetraynes and Their Transport Properties in Single‐Molecule Junctions

The synthesis and characterisation is described of six diaryltetrayne derivatives [Ar‐(C?C)₄‐Ar] with Ar=4‐NO₂‐C₆H₄‐ ( NO₂4 ), 4‐NH(Me)C₆H₄‐ ( NHMe4 ), 4‐NMe₂C₆H₄‐ ( NMe₂4 ), 4‐NH₂‐(2,6‐dimethyl)C₆H₄‐ ( DMeNH₂4 ), 5‐indolyl ( IN4 ) and 5‐benzothienyl ( BTh4 ). X‐ray molecular structures are reported for NO₂4 , NHMe4 , DMeNH₂4 , IN4 and BTh4 . The stability of the tetraynes has been assessed under ambient laboratory conditions (20 °C, daylight and in air): NO₂4 and BTh4 are stable for at least six months without observable decomposition, whereas NHMe4 , NMe₂4 , DMeNH₂4 and IN4 decompose within a few hours or days. The derivative DMeNH₂4 , with ortho‐methyl groups partially shielding the tetrayne backbone, is considerably more stable than the parent compound with Ar=4‐NH₂C₆H₄ ( NH₂4 ). The ability of the stable tetraynes to anchor in Au|molecule|Au junctions is reported. Scanning‐tunnelling‐microscopy break junction (STM‐BJ) and mechanically controllable break junction (MCBJ) techniques are employed to investigate single‐molecule conductance characteristics.     

DABCO mediated one pot synthesis of 2-(3-benzyl-2, 6-dioxo-3, 6-dihydropyrimidin-1[2H]-yl)-N-(4-(1, 3-dioxo-1H-benzo [de]isoquinolin-2[3H]-yl) aryl) acetamides as antimicrobial agents

We report herein DABCO mediated one pot synthesis of 2-(3-benzyl-2, 6-dioxo-3,6-dihydropyrimidin-1[2H]-yl)-N-(4-(1,3-dioxo-1H-benzo[de]isoquinolin-2[3H]-yl) aryl) acetamides ( 4a-j ). The silent features of this new one pot synthesis include the shorter reaction time, high yields, simple workup, and simultaneous formation of N-Amide and N-benzyl bonds in the one pot. The newly synthesized compounds ( 4a-j ) were characterized by different spectral techniques such as IR, ¹H-NMR, ¹³C-NMR, HRMS. All the synthesized compounds were evaluated for their anti-bacterial and anti-fungal activities. The anti-bacterial activities results reveal that the compounds 4a , 4g , 4i , and 4j are most active against S. aureus. In the case of B. subtilis the compounds 4a , 4i , and 4j are found to be most active. The compounds 4c , 4e , 4i , and 4j are most active against E. coli. In the case of P. aeruginosa 4a , 4i & 4j are found to be more active. On the other hand, the anti-fungal activity result shows that the compounds 4d , 4f , 4i , and 4j are more active against A. niger. The compounds 4a , 4d , 4i , and 4j are found to be more active against C. albicans.     

One‐Pot Multicomponent Synthesis of Novel Substituted Imidazo[1,2‐a]Pyridine Incorporated Thiazolyl Coumarins and their Antimicrobial Activity

A series of novel substituted imidazo[1,2‐a]pyridine incorporated thiazolyl coumarin derivatives ( 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n , 4o , 4p , 4q , 4r , 4s , 4t ) were synthesized in good yields via one‐pot multicomponent condensation of substituted imidazo[1,2‐a]pyridine‐3‐carbaldehyde ( 3a , 3b , 3c , 3d , 3e ), thiosemicarbazide ( 2 ), and substituted 3‐(2‐bromoacetyl)‐2H‐chromen‐2‐ones ( 1a , 1b , 1c , 1d )/2‐(2‐bromoacetyl)‐3H‐benzo[f]chromen‐3‐one ( 1e ) in refluxing ethanol with catalytic amount of acetic acid. All the synthesized compounds ( 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n , 4o , 4p , 4q , 4r , 4s , 4t ) have been characterized by IR, NMR, and mass spectral studies as well as elemental analyses and evaluated for their in vitro antimicrobial activity against different bacterial and fungal strains. All the compounds displayed moderate antibacterial activity with minimum inhibitory concentration 150 µg/mL, but none of the compounds have shown any antifungal activity.     

DBU‐catalyzed Multicomponent Synthesis: Facile Access of 4,5,6,9‐Tetrahydro‐pyrido[3,2‐c]quinolines

An efficient synthesis of 4H,5H,6H,9H‐pyrido[ij]pyrano[3,2‐c]quinolines 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n , 4o , 4p , 4q , 4r , 4s , 4t as well as spiro compound 6 was achieved via multicomponent approach by using DBU as a nucleophilic catalyst under the remarkably mild reaction conditions. The structures of the compounds were characterized by ¹H NMR, ¹³C NMR, and mass spectral analysis. An attractive feature of this inexpensive protocol includes facile synthesis, shorter reaction time, ease of work‐up, large number of functional group tolerance, and good to excellent yields with high purity.     

Substitution at C-4 in 3,5-disubstituted 4H-1,2,6-thiadiazin-4-ones

3,5-Diaryl-4H-1,2,6-thiadiazin-4-ones react with NaBH₄ to give the 3,5-diaryl-4H-1,2,6-thiadiazin-4-ols and with MeLi to give 4-methyl-3,5-diaryl-4H-1,2,6-thiadiazin-4-ols. The latter dehydrate with p-toluenesulfonic acid to give (3,5-diarylthiadiazin-4-ylidene)methanes. (3,5-Diphenyl-4H-1,2,6-thiadiazin-4-ylidene)methane 15 suffers mono bromination with NBS to give bromo(3,5-diphenyl-4H-1,2,6-thiadiazin-4-ylidene)methane 17. Dichloro- and dibromo(3,5-diphenyl-4H-1,2,6-thiadiazin-4-ylidene)methanes 18 and 19 are formed directly from the 3,5-diphenylthiadiazin-4-one 9 via the Appel reaction using Ph₃P and CCl₄ or CBr₄, respectively. 3,5-Diarylthiadiazin-4-ones treated with P₂S₅ give 3,5-diarylthiadiazine-4-thiones that react with tetracyanoethylene oxide to give the (thiadiazin-4-ylidene)malononitriles. Finally, the 3,5-diphenylthiadiazine-4-thione 20 reacts with ethyl diazoacetate to give ethyl 2-(3,5-diphenyl-4H-1,2,6-thiadiazin-4-ylidene)acetate 26. The above reactions show that a variety of substitutions at C-4 of 3,5-diaryl substituted 1,2,6-thiadiazin-4-ones can be achieved, which extends the potential applications of this heterocycle. All compounds are fully characterized and a brief comparison of their spectroscopic properties is given.     

Synthesis,Crystal Structure,and Insecticidal Activity of (Z)‐Nitenpyram Derivatives with Optical Activity

Fourteen novel nitenpyram derivatives (Z)‐4‐substituted‐3‐acetyl‐6‐methylamino ?6‐[N‐(6‐chloro‐3‐pyridinylmethyl)‐N‐ethyl]amino‐5‐nitno‐2‐oxa‐5‐hexene 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n were synthesized, and their structures were confirmed by ¹H NMR, IR, and elemental analysis. The stereostructure of 4h was determined by the single‐crystal X‐ray analysis. The preliminary bioassay tests showed that most of the title compounds exhibited good insecticide activities against Nilaparvata lugens as well as Aphis medicaginis at 500 mg/L, whereas compound 4h afforded the best activity, with 100% mortality against A. medicaginis at 100 mg/L.     

离子液体的组成及溶剂性质与木瓜蛋白酶催化特性的关系

离子液体的组成及溶剂性质对木瓜蛋白酶催化D,L-对羟基苯甘氨酸甲酯不对称水解反应有重要的影响. 木瓜蛋白酶在含CnMIm·BF4(n=2~6)介质中表现出较高的活性、对映体选择性及稳定性, 而在含有C4MIm·HSO4, C4MIm·Cl, C4MIm·NO3, C4MIm·CH3COO的介质中表现较低的对应值. 在含有CnMIm·BF4(n=2~6)的介质中, 酶活性随离子液体的极性增大而提高, 但在含有C4MIm·HSO4, C4MIm·Cl, C4MIm·NO3, C4MIm·CH3COO的介质中随离子液体的极性增大反而降低. 木瓜蛋白酶的对映体选择性和稳定性均随着离子液体的疏水性增大而提高. 荧光分析结果表明, 离子液体对酶分子构象具有显著的影响. 在CnMIm·BF4(n=2~6)的介质中, 木瓜蛋白酶的最大荧光发射波长(λmax)均蓝移, 而在含有C4MIm·HSO4, C4MIm·Cl, C4MIm·NO3或C4MIm·CH3COO的介质中, λmax均红移. 与CnMIm·BF4(n=2~6)相比, 在C4MIm·HSO4, C4MIm·Cl, C4MIm·NO3或C4MIm·CH3COO中, 酶分子构象的变化较大, 暴露的疏水区域较多.     

Transport behavior in isomeric alcohols. I. The conductance of tetraalkylammonium salts in isobutyl and isopentyl alcohols at 25°C

Conductance measurements at 25°C have been carried out on Pr₄NBr, Bu₄NBr,n-Pe₄NPr, Pr₄NI, Bu₄NI,n-Pe₄NI, Bu₄NClO₄, Bu₄NBF₄, and Bu₄PClO₄ in isobutyl alcohol and on Bu₄NBr and Bu₄NClO₄ in isopentyl alcohol. The main purpose of the measurements was to investigate the effect of increased branching in the alkyl portion of the alcohol on both ionic mobilities and ionic association. Comparison is made with the two isodielectric solvents butanone andn-butyl alcohol. Branching appears to produce little change in ionic mobilities and approximately a 10% increase in association.     

Comparison of the crystal structures of sodium orthosilicate,Na4SiO4, and sodium orthogermanate,Na4GeO4

The crystal structures of Na₄SiO₄ and Na₄GeO₄ are isotypic, despite a difference in coordination numbers: in Na₄SiO₄ only one of the four symmetrically independent sodium atoms is four coordinated, in Na₄GeO₄ two of them are.

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Vergleich der Kristallstrukturen von Natriumorthosilikat, Na₄SiO₄, und Natriumorthogermanat, Na₄GeO₄ (Kurze Mitteilung)

Zusammenfassung Die Kristallstrukturen von Na₄SiO₄ und Na₄GeO₄ sind isotyp, trotz eines Unterschiedes in den Koordinationszahlen: im Na₄SiO₄ ist nur eines der symmetrisch unabhängigen Natriumatome vierfach koordiniert, während es im Na₄GeO₄ derer zwei sind.

     

2-Trif luoromethyl-4H-thiochromen-4-one and 2-trif luoromethyl-4H-thiochromene-4-thione: Synthesis and reactivities

2-Trifluoromethyl-4H-thiochromene-4-thione obtained from 2-trifluoromethyl-4H-thiochromen-4-one and P₂S₅ reacts with aromatic amines, hydrazine hydrate, phenylhydrazine, and hydroxylamine at the C(4) atom of the chromene ring to give the corresponding anils, azine, hydrazones, and oxime of thiochromone. 2-Trifluoromethyl-4H-thiochromen-4-one is oxidized by hydrogen peroxide in AcOH into 4-oxo-2-trifluoromethyl-4H-thiochromene 1,1-dioxide and reduced by NaBH₄ to 2-trifluoromethyl-4H-thiochromen-4-ol or cis-2-(trifluoromethyl)thiochroman-4-ol. When treated with hydrazine hydrate, thiochromen-4-one gives 3(5)-(2-mercaptophenyl)-5(3)-trifluoromethylpyrazole. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 504–509, March, 2006.     

Synthesis and Biological Evaluation of Novel Chalcone and Pyrazoline Derivatives Bearing Substituted Vanillin Nucleus

A series of novel chalcone 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l and pyrazoline 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l derivatives have been synthesized as potential antibacterial agents. The pyrazoline derivatives 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l have been synthesized by reaction of various chalcones 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l with hydrazine hydrate in the presence of acetic acid. The chalcones 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l were prepared by the condensation of key aldehyde 3 with appropriate acetophenone using basic condition and ethanol as a solvent. The key aldehyde 3 has been synthesized by reacting 2‐(chloromethyl)‐3‐methyl‐4‐(2,2,2‐trifluoroethoxy)pyridine hydrochloride and vanillin. The structures of the new compounds were established on the basis of ¹H‐NMR, mass, IR, and elemental analysis data. All the newly synthesized compounds were screened for their antibacterial activity against Escherichia coli, Salmonella typhi (Gram‐negative bacteria), Staphylococcus aureus, Micrococcus luteus (Gram‐positive bacteria) and antifungal activity against Candida albicans (fungi).     

Etude des Phases Na4XO4 (X = Sn,Pb) et de K4SnO4 par Spectrophotométrie d′Absorption Infrarouge et Diffusion Raman

Infrared and Raman Studies of the Na₄SnO₄, Na₄PbO₄, and K₄SnO₄ phases The vibrational spectra of the Na₄SnO₄, Na₄PbO₄, and K₄SnO₄ phases have been studied for the first time. They characterize isolated tetrahedral XO₄ groups. The assignments of the i.r. and Raman frequencies have been made by a factor group analysis. The force constants, calculated for K₄SnO₄ using the obtained spectroscopic data, show the covalent character of the Sn? O bond.     

An Efficient Microwave‐Assisted Synthesis and Antimicrobial Activity of Novel 2‐Amino 3‐Cyano Pyridine Derivatives using Two Reusable Solid Acids as Catalysts

Two solid acids, Fe³⁺ K‐10 montmorillonite clay and HY‐zeolite, have been employed efficiently for synthesis of 2‐amino 3‐cyano pyridines 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l , 4m , 4n , 4o , 4p , 4q , 4r , 4s , 4t , 4u , 4v , 4w , 4x by multicomponent reaction of 3‐acetyl 4‐hydroxy coumarin 1a , 1b , 1c , 1,3‐diphenyl‐1H‐pyrazole‐4‐carbaldehyde 2a , 2b , 2c , 2d , 2e , 2f , 2g , 2h , malononitrile 3 , and ammonium acetate. Both the catalysts are recoverable and recyclable. The main significant of this procedure is short reaction time, high yields, easy workup procedure, and being environmentally friendly. The structures of all the compounds have been well characterized by IR, ¹H NMR, ¹³C NMR, and mass spectral data. All the synthesized compounds were screened for their antimicrobial and antifungal activities.     

The Synthesis of Some New (S)‐1‐Aryl‐N‐(1‐hydroxy‐3‐phenylpropan‐2‐yl)‐5‐methyl‐1H‐1,2,3‐triazole‐4‐carboxamide

Some new (S)‐1‐aryl‐N‐(1‐hydroxy‐3‐phenylpropan‐2‐yl)‐5‐methyl‐1 H‐1,2,3‐triazole‐4‐carboxamides 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j have been synthesized and established by ¹H and ¹³C NMR, IR, MS spectra, CHN analyses, and x‐ray diffraction crystallography. The molecular conformation and packing is stabilized by interactions of intermolecular H‐bond O2’‐H2'···O1, O2‐H2···O1’ and intramolecular H‐bond N4’‐H4'N···N3’, N4’‐H4'N···O2’, N4‐H4N···N3, N4‐H4N···O2. The two rings of five numbers were formed by H‐bond in a molecular.     

The use of isotopic substitution and matrix isolation techniques in determining molecular constants for group IVA tetrahalides

Improved values of molecular constants of group IVA tetrahalides are reported. Accurate frequencies, including those of different isotopically substituted species, have been determined using matrix isolation spectroscopy in conjunction with isotope techniques (for SiF₄, GeF₄, SiCl₄, Si³⁵Cl₄, SiBr₄, GeBr₄, ⁷⁴GeBr₄, ^70/76GeBr₄, SnBr₄, ¹¹⁶SnBr₄ and ¹²⁴SnBr₄) and from vapour -phase IR spectra (for SiF₄, GeF₄, ⁷⁴GeF₄, SiCl₄, Si³⁵Cl₄ SiBr₄, GeBr₄, ⁷⁴GeBr₄, SnBr₄, ¹¹⁶SnBr₄ and ¹²⁴SnBr₄). Band contour analyses, often rendered difficult by isotopic effects and hot-band progressions, were simplified by measuring the spectra of isotopically pure compounds (e.g. ⁷⁴GeF₄, ¹¹⁶Sn³⁵Cl₄) and by measurements at lower temperatures (SiF)₄. The isotopic shifts, Coriolis coupling and force constant values determined in this study are more accurate than those previously reported for some of the molecules. In addition to the presentation of new data the known spectral information concerning the other tetrahalides of silicon, germanium and tin are reviewed.     

Vibrational spectra of NH4-Ln(SO4)2·4H2O/D2O (LnLa and Ce)

Infrared and Raman spectra of NH₄Ce(SO₄)₂·4H₂O, NH₄La(SO₄)₂·4H₂O and the deuterated compounds NH₄Ce(SO₄)₂·4D₂O and NH₄La(SO₄)₂·4D₂O have been analysed. Splittings indicating the presence of two types of SO₄ ions are not observed. The SO bond strengths of the different SO₄ units are not significantly different. The SO₄ ion is distorted in these compounds. Deuteration causes changes in the SO₄ bond strength. Three crystallographically distinct water molecules exist in the unit cell.     

Die Bildung von PPh4[WOCl4 · THF] und PPh4Cl · 4As4S3 aus W(CO)6 und PPh4[As2SCl5] sowie ihre Kristallstrukturen

Formation of PPh₄[WOCl₄ · THF] and PPh₄Cl · 4As₄S₃ from W(CO)₆ and PPh₄[As₂SCl₅] and their Crystal Structures When W(CO)₆ and PPh₄[As₂SCl₅] are irradiated with UV light in tetrahydrofurane, PPh₄[WOCl₄ · THF], PPh₄ Cl· 4As₄S₃ and PPh₄[Cl₂H] are obtained. X-ray crystal structure determinations were performed. PPh₄[WOCl₄ · THF], monoclinic, space group P2₁/c, Z = 4, a = 1207.5(2), b = 1003.7(2), c = 2642.0(5) pm, β = 114.71(1)°, R = 0.049% for 2824 reflexions; PPh₄⁺ and [WOCl₄. THF]^? ions are present, the WOCl₄ group having the shape of a tetragonal Pyramid with a short W ? O bond (169 pm) and the THF molecule being weakly associated (W? O 236 pm). PPh₄Cl · 4AsS₃, tetragonal, I4₁/a, Z = 4, a = 1742.3(3), c = 1664.5(4) pm, R = 0.066% for 1350 reflexions; it consists of separate PPh₄⁺ and Cl^? ions and As₄S₃ molecules.     

Energetics of formation of alkali and ammonium cobalt and zinc phosphate frameworks

Alkali and ammonium cobalt and zinc phosphates show extensive polymorphism. Thermal behavior, relative stabilities, and enthalpies of formation of KCoPO₄, RbCoPO₄, NH₄CoPO₄, and NH₄ZnPO₄ polymorphs are studied by differential scanning calorimetry, high-temperature oxide melt solution calorimetry, and acid solution calorimetry.α-KCoPO₄ and γ-KCoPO₄ are very similar in enthalpy. γ-KCoPO₄ slowly transforms to α-KCoPO₄ near 673 K. The high-temperature phase, β-KCoPO₄, is 5-7 kJ mol⁻¹ higher in enthalpy than α-KCoPO₄ and γ-KCoPO₄. HEX phases of NH₄CoPO₄ and NH₄ZnPO₄ are about 3 kJ mol⁻¹ lower in enthalpy than the corresponding ABW phases. There is a strong relationship between enthalpy of formation from oxides and acid-base interaction for cobalt and zinc phosphates and also for aluminosilicates with related frameworks. Cobalt and zinc phosphates exhibit similar trends in enthalpies of formation from oxides as aluminosilicates, but their enthalpies of formation from oxides are more exothermic because of their stronger acid-base interactions. Enthalpies of formation from ammonia and oxides of NH₄CoPO₄ and NH₄ZnPO₄ are similar, reflecting the similar basicity of CoO and ZnO.