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.     

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.     

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.     

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.     

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.     

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.     

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.

     

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.     

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.     

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).     

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.     

2,4-Diaminodihydropyridine

Aminolysis of 4-alkylamino- and 4-dialkylamino-2-methylthiodihydropyridines (· HI)1, 2 resp.. under various reaction-condition leads to assymmetrically or symmetrically substituted 2,4-bisalkylamino- or 2,4-bisdialkylamino-and 2-alkylamino-4-dialkylamino- or 2-dialkylamino-4-alkylaminodihydro-pyridines3, 4, 5, 6 resp. On treatment with alkali only the aminogroup in pos. 4 of the pyridines3, 4, 5, 6 is hydrolyzed and 4-hydroxy-2-aminopyridines9 are formed. Different substituted 2,4-diaminodihydropyridines3, 4, 5, 6 can also be synthesized by reaction of 4-hydroxy-2-aminopyridines (·HCl)9 with amines. Also the aminolysis of 4-alkylamino-annd 4-dialkylaminodihydropyridinthiones7, 8 resp. is described.

     

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.     

A comparative experimental and theoretical investigation of hydrogen‐bond,halogen‐bond and π–π interactions in the solid‐state supramolecular assembly of 2‐ and 4‐formylphenyl arylsulfonates

To explore the operational role of noncovalent interactions in supramolecular architectures with designed topologies, a series of solid‐state structures of 2‐ and 4‐formylphenyl 4‐substituted benzenesulfonates was investigated. The compounds are 2‐formylphenyl 4‐methylbenzenesulfonate, C₁₄H₁₂O₄S, 3a , 2‐formylphenyl 4‐chlorobenzenesulfonate, C₁₃H₉ClO₄S, 3b , 2‐formylphenyl 4‐bromobenzenesulfonate, C₁₃H₉BrO₄S, 3c , 4‐formylphenyl 4‐methylbenzenesulfonate, C₁₄H₁₂O₄S, 4a , 4‐formylphenyl 4‐chlorobenzenesulfonate, 4b , C₁₃H₉ClO₄S, and 4‐formylphenyl 4‐bromobenzenesulfonate, C₁₃H₉BrO₄S, 4c . The title compounds were synthesized under basic conditions from salicylaldehyde/4‐hydroxybenzaldehydes and various aryl sulfonyl chlorides. Remarkably, halogen‐bonding interactions are found to be important to rationalize the solid‐state crystal structures. In particular, the formation of O…X (X = Cl and Br) and type I X…X halogen‐bonding interactions have been analyzed by means of density functional theory (DFT) calculations and characterized using Bader's theory of `atoms in molecules' and molecular electrostatic potential (MEP) surfaces, confirming the relevance and stabilizing nature of these interactions. They have been compared to antiparallel π‐stacking interactions that are formed between the arylsulfonates.     

Influence of a new axial impeller on K L a and xylanase production by Penicillium canescens 10-10c

The effects of a new axial impeller (HTPG4) on oxygen volumetric transfer coefficient, K _L a, and xylanase production by Penicillium canescens 10-10c were studied and compared for dual-impeller systems, one with one DT4 impeller below and one HTPG4 above (DT4-HTPG4) and one with two DT4 (DT4-DT4) impellers, in a 5-L bioreactor. The volumetric coefficient of oxygen transfer was measured in culture medium using a gassing-out method at different gassing rates and agitation speeds. We observed that the DT4-HTPG4 combination provided better K _L a performance than the DT4-DT4 combination. The two combinations were also tested for their influence on xylanase production by a filamentous microorganism; P. canescens 10-10c. These experiments demonstrated that the DT4-HTPG4 combination impeller enhanced enzyme production up to 23% compared with the DT4-DT4 combination at an aeration rate of 1 vvm and an agitation speed of 600 rpm. The main cause for this difference is thought to be a higher shear stress generated by the DT4-DT4 combination, which damages the mycelium of P. canescens and decreases xylanase production.     

Synthese und Charakterisierung von Tetrabromoferraten(III) AFeBr4 mit einwertigen Kationen A  Cs,Rb, Tl,NH4, K,Na, Li,Ag

Preparation and Characterization of Tetrabomoferrates(III) AFeBr₄ with Monovalent Cations A ? Cs, Rb, Tl, NH₄, K, Na, Li, Ag Tetrabromoferrates(III) AFeBr₄ of the monovalent cations A ? Cs, Rb, Tl, NH₄, Na, Ag, Li have been prepared in closed ampoules by reaction of the appropriate bromides with iron and an excessive amount of bromine. The dark red compounds were characterized by DTA, Raman spectroscopy and X-ray powder diffraction. Their crystal structures have been assigned to five structure types, containing FeBr₄ anions. The coordination number runs from 12 (Cs⁺, Rb⁺) over 10 (NH₄⁺) and 8 (K⁺), to 6 (Na⁺, Ag⁺, Li⁺). Lattice parameters for all compounds see “Inhaltsübersicht”. CsFeBr₄ and RbFeBr₄ crystallize orthorhombic in the BaSO₄-type, NH₄FeBr₄ monoclinic in the KAlBr₄-type, KFeBr₄ orthorhombic in the GaGaCl₄-type, NaFeBr₄ monoclinic in the NaGaBr₄-type, AgFeBr₄ and LiFeBr₄ monoclinic in the LiAlCl₄-type, while the structure of TlFeBr₄ is still unknown.     

Synthesis of new amides of the <Emphasis Type="Italic">N</Emphasis>-methylpiperazine series

New carboxylic acid amides containing an N-methylpiperazine fragment were synthesized by reactions of 1-methylpiperazine or 3- and 4-(4-methylpiperazin-1-ylmethyl)aniline with 4-chlorobenzoyl chloride and of 4-methyl-3-nitroaniline with 4-(4-methylpiperazin-1-ylmethyl)benzoyl chloride or benzotriazol-1-yl 4-(4-methylpiperazin-1-ylmethyl)benzoate. 4-Chloro-N-[4-(4-methylpiperazin-1-ylmethyl)phenyl]benzamide reacted with imidazole, quinolin-5-amine, and 2-methylquinolin-5-amine to give substituted 4-amino-N-[4-(4-methylpiperazin-1-ylmethyl)phenyl]benzamides. 4-Methyl-3-nitrophenyl-4-methylpiperazin-1-yl-substituted benzamides were reduced with hydrazine hydrate over Raney nickel to obtain N-(3-amino-4-methylphenyl)-4-(4-methylpiperazin-1-ylmethyl)benzamide as key intermediate in the synthesis of antileukemic agent imatinib and its isomer with alternative position of the amide group, 4-[(3-amino-4-methylphenylamino)methyl]phenyl-(4-methylpiperazin-1-yl)methanone.