Synthesis and X‐Ray Analysis of a New [6]Helicene

A new disubstituted hexahelicene derivative 3 bearing methoxy functions at positions 3 and 14 has been prepared in racemic form through a Heck reaction followed by photocyclodehydrogenation. Suitable crystals of rac‐3 were analyzed by X‐ray crystallography and showed similar geometry to the structure of hexahelicene itself. Deprotection of 3 using boron tribromide led to 3,14‐dihydroxyhexahelicene 4 in quantitative yield. The complexation of transition metal atoms seemed to be quite possible by these two bidentate hexahelicene derivatives.     

Synthesis and Characterization of Alkyl and Aryl‐(4‐methyl‐6‐nitro‐quinolin‐2‐yl)amines: X‐Ray Structures of Ethyl and Cyclohexyl‐(4‐methyl‐6‐nitro‐quinolin‐2‐yl)amine

Abstract

We have synthesized and characterized a series of alkyl and aryl‐(4‐methyl‐6‐nitro‐quinolin‐2‐yl)amines through a high‐yield, three‐step procedure starting from 4‐methylquinolin‐2‐ol. Nitration using concentrated nitric/sulfuric acids, followed by chlorination in phosphorus oxychloride, yielded 2‐chloro‐4‐methyl‐6‐nitro‐quinoline. All of the intermediates and aminated products have been characterized by multinuclear (¹H and ¹³C) NMR spectroscopy, elemental analysis, and, in the case of the two title compounds (ethyl and cyclohexyl‐(4‐methyl‐6‐nitro‐quinolin‐2‐yl)amine), a single crystal X‐ray structure was obtained to verify the nature of the new materials.     

X‐Ray Photoelectron‐ and Auger‐Spectroscopic Study of Superstoichiometric Fluorographite‐Like Materials

Xray photoelectron spectroscopy (XPS) and Auger spectroscopy methods were used to study industrial fluorographitelike fluorocarbon materials (FCMs) of superstoichiometric CF_1.25–1.33 composition [fluorosibunite (FS) and T900 fluorinated soot (FT)] and fluorinated graphites of CF_0.88–1.08 composition. Based on XPS analysis, models were proposed for the surface layer structures in nanofragments of the FCMs and fluorographite. The main structural element of the FCMs and fluorographites studied here is a corrugated carbon network with CF and CF₂ groups of several types. The CF networks of the FCM structures contain holes formed upon fluorination of the initial carbon materials and filled with alternating CF and CF₂ groups. The bond energies of the inner C1s and F1s levels and the kinetic energies of F KLL Auger spectra suggest a covalent nature of all types of bonds between the carbon and fluorine atoms. Calculations using XPS data revealed common and specific features in correlations between the volume stoichiometry of the FCMs and fluorographites and the atomic F/C ratios in the surface layers of the materials.     

Synthesis and study of the properties of the solid solutions K2Y1−x Tb(Tm) x (MoO4)(PO4) and K2Y1−x Tm x (MoO4)(PO4)0.95(VO4)0.05

The solid solutions K₂Y_1?x Tb(Tm) _x (MoO₄)(PO₄) and K₂Y_1?x Tm _x (MoO₄)(PO₄)_0.95(VO₄)_0.05 were synthesized, which are isostructural and crystallize in the orthorhombic crystal system (space group Ibca). The luminescence intensity of the terbium-containing samples increases with increase in the terbium content. The thulium-containing samples are characterized by intense luminescence in the blue spectral region and concentration quenching of luminescence. The introduction of the vanadate anion adversely affects the luminescence intensity.     

Synthesis and Chemical Transformations of 6‐(Morpholine‐4‐sulfonyl)‐quinoline‐2,3,4‐tricarboxylic Acid

The article describes an effective synthesis and chemical transformations of 6‐(morpholine‐4‐sulfonyl)‐2,3,4‐quinolinetricarboxylic acid. The key step is the Pfitzinger reaction of 3,3‐dichloro‐2‐oxo‐2,3‐dihydro‐1H‐indole with diethyl 2‐oxosuccinate. Selective 2‐decarboxylation of the tricarboxylic acid followed by reaction of the resulting anhydride with a primary amine led to the formation of the 1,3‐dioxo‐2,3‐dihydro‐1H‐pyrrolo[3,4‐c]quinoline scaffold with interesting pharmacological activity.     

Synthesis and Crystallographic Study of1,6‐bis‐(N‐phenothiazinyl)‐2,4‐hexadiyne

1,6‐bis‐(N‐phenothiazinyl)‐2,4‐hexadiyne (I) was synthesized in high yield by oxidative coupling of N‐propargyl phenothiazine. Grown from methylene chloride‐hexane solution, I is a monoclinic crystal, space group C2/c a=14.9500(18) Å; b=13.5512(15) Å; c=12.0116(10) Å; β=102.628(9)° Å; V=2374.6(4) ų. The intermolecular distances and arrangement of I in the unit cell preclude the usual diacetylene reactivity. Nevertheless, heating of I at 145°C results in decomposition of I to phenothiazine and a dark brown solid. In addition, cation‐radicals of I were prepared by oxidation with nitrosonium tetrafluoroborate and iodine to give stable ion‐radical salts.     

Triple C-H Bond Activation of a Nickel-Bound Methyl Group: Synthesis and X-Ray Structure of a Carbide Cluster (NiCp)(6)(μ(6)-C)

A new hexanuclear cyclopentadienylnickel carbide cluster (NiCp)(6)(μ(6)-C) (1) was obtained through the thermolysis of the alkene complex [NiCp(CH(3))(η(2)-CH(2)═CHC(4)H(9))] (4). The X-ray molecular structure of 1 (monoclinic; P2(1)/c; Ni-C(carbide) = 1.767(4)-2.109(4) ?) reveals a highly deformed octahedral arrangement of nickel atoms with two octahedron edges opened (Ni-Ni bonding distances = 2.410(1)-2.623(1) ?, Ni···Ni nonbonding distances = 3.107(2) and 3.108(2) ?). Cluster 1 is the first example of a homoleptic, cyclopentadienylnickel carbide cluster. Moreover, (13)C-labeling studies proved that the carbido ligand in cluster 1 originated from the Ni-bound methyl group. This transformation requires a triple C-H bond activation in the methyl group, which has not been observed so far for late transition metal compounds.     

Synthesis and study of 4‐(4′‐n‐alkoxybenzoyloxybenzoyl)‐4′′‐n‐butoxyanilides

Thirteen compounds with ester and amide linkages were synthesized and their mesogenic properties evaluated. Methyl to n‐propyl derivatives exhibit nematic phases, n‐butyl to n‐decyl derivatives exhibit smectic and nematic mesophases, whereas n‐dodecyl to n‐octadecyl derivatives exhibit only smectic phases. All the smectic homologues exhibit smectic C phases. Middle members of the homologous series exhibit polymorphism of smectic mesophase. A plot of transition temperatures versus number of carbon atoms in the alkoxy chain reveals an odd–even effect for nematic–isotropic transition temperatures. Nematic–isotropic and smectic–cholesteric thermal stabilities of the prepared compounds (series I) are higher compared to those of previously reported compounds, series A, B and C. The results indicate that a simple reversal of a central linkage has a dramatic effect on the appearance of smectic mesophase in a homologous series. The structures of the synthesized compounds were characterized using elemental analysis, thin‐layer chromatography and spectral data.     

Simple and Convenient Synthesis of 4‐Unsubstituted‐3‐(3‐Oxoalkyl)isocoumarins

A simple transformation of 2‐alkylfurans and 2‐formylbenzoic acids into 4‐unsubstituted 3‐(3‐oxoalkyl)isocoumarins is described. It is based on the synthesis of 2‐(2‐carboxybenzyl)furans followed by their acid‐catalyzed recyclization to the target isocoumarins.     

Synthesis of (E)‐ and (Z)‐5‐(Bromomethylene)furan‐2(5H)‐one by Bromodecarboxylation of (E)‐2‐(5‐Oxofuran‐2(5H)‐ylidene)acetic Acid

(E)‐ and (Z)‐5‐(bromomethylene)furan‐2(5H)‐one have been prepared starting from the commercially available adduct between furan and maleic anhydride. A bromodecarboxylation reaction is a key step in the synthesis. The reaction gives the (E)‐ or (Z)‐5‐(bromomethylene)furan‐2(5H)‐one as the major product, dependent on the method used in the bromodecarboxylation.     

One‐Pot Synthesis of 5‐Alkylfuran‐2(5H)‐ones

5‐Alkylfuran‐2(5H)‐ones can be efficiently obtained using a one‐pot approach, starting from methyl 3‐nitropropanoate and aldehydes, in ethyl acetate, with Amberlyst A‐21 as catalyst, in 60–90% overall yield.     

One‐Pot Synthesis of Pyrazole‐5(3)‐carboxyamides

Abstract

A convenient one‐pot synthesis of eight pyrazole‐5(3)‐carboxyamides from the reaction of the 5(3)‐trichloromethylpyrazoles with amines, in good yield, is reported. These reactions show that the trichloromethyl group is a convenient precursor to carboxyamide groups.     

Synthesis and Structure of Large Single Crystal of TPAF-AlPO_4-5 Molecular Sieve

A large single crystal of TPAF-AlPO4-5 molecular sieve was synthesized by hydrothermal crystallization in the presence of ammonium fluoride. Starting material composition was · 1 P2O5 · 1 Al2O3 · 2. 2 TPAOH · 1. 7 NH4F ·318 H2O. The crystal size has a hexagonal prism with 80μm across and 500μm length.The structure of tetrapropylarnmonium fluoride - aluminium phosphate type-5 was investigated with X-ray diffraction. The unit cell composition is 12AlPO4 · TPAF, space group P6cc (a= 13. 740(5), c= 8. 474(4) A ). Average bond distances are: P-O 1. 564A and Al-O 1. 640A ,which may be due to the partial disorder of the arrangement of P, Al in the framework. The angles of O-T-O and T-O-T (T?P, Al) are 102-116° and 148-176°, respectively. Residue electron density was not well enough defined to give a precise position for tetrapropylammonium fluoride (TPAF). The template agent, TPA cations, situate in the 12-ring channels and F- anions locate in double 4-rings near the 12-ring channels. Fixing atomic     

Synthesis and Crystal Structure Characterization of [Zr(HPO_4)(PO_4)F_2]·1.5H_3NCH_2CH_2NH_3

Thesynthesisofcrystallinezirconiumphosphateswasfirstreportedinl964byClearfieldandStynes['J,whodeterminedtheformulaasZr(HPO,),.H,O(a-ZrP)basedonchemicalcomposition,dehydrationandion-exchangebe-haviour'Sincethen,manyothercrystallinezirconiumphosphate,suchasZr(HPO,)(g-ZrP),Zr(HPO'),.H,O(Y-ZrP),havebeenprepared['.'1.Thesephosphatesconsistedofalternate,cross-linkedlayersofZrO,octahedraandPO'tetrahedrawithwatermoleculesaccommodatedininterlamellarfashion.a-Zirco-niumphosphate,Zr(HPO'),.…     

General and Facial Synthesis of 2‐Amino‐5‐halogenpyrimidine‐4‐carboxylic Acids and Their Derivatives

A facile synthetic approach to 2‐amino‐5‐halogen‐pyrimidine‐4‐carboxylic acids from 5‐halogen‐2‐methylsulfonylpyrimidine‐4‐carboxylic acid by nucleophilic displacement of the methylsulfonyl group with primary and secondary aliphatic amines has been developed. The titled amino acids underwent decarboxylation, yielding 2‐amino‐5‐halogenpyrimidines. Starting from 2‐amino‐5‐chloropyrimidine‐4‐carboxylic acid chlorides, 2‐[5‐chloro‐2‐(amino)‐4‐pyrimidinyl]‐2‐oxo‐1‐(2‐pyridyl)‐ethyl cyanides were obtained in excellent yields.     

Facile and Practical Synthesis of (R)‐6‐Br‐2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl

A new enantiopure 6‐monobromo‐substituted BINAP has been prepared via a one‐step nickel‐catalyzed coupling reaction in moderate yield. It is an important intermediate for asymmetric 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP) derivatives. Its structure was elucidated by NMR spectral and elemental analysis.     

Synthesis,Characterization and Photocrosslinking Properties of Poly(1‐(4‐Methacrylamidophenyl)‐1‐(4‐nitrophenyl)prop‐1‐en‐3‐one)

The phenylmethacrylamide monomer, 1‐(4‐methacrylamidophenyl)‐1‐(4‐nitrophenyl)prop‐1‐en‐3‐one (MPNP) containing a photosensitive group was synthesized by reacting 4‐nitrocinnamoylaniline with methacryloyl chloride in the presence of triethylamine at 0–5°C. The functional monomer, MPNP was polymerized in ethyl methyl ketone (EMK) under nitrogen atmosphere at 70°C using benzoyl peroxide (BPO) as the initiator. The synthesized polymer was characterized by UV, IR, ¹H‐NMR and ¹³C‐NMR spectroscopy. The molecular weight data of the polymer as obtained from gel permeation chromatography suggests a higher tendency for chain termination by radical recombination than disproportionation. The thermal studies of the polymer were obtained from thermogravimetric analysis. The glass transition temperature of the polymer was determined by differential scanning calorimetry. The solubility of the polymer was tested in various organic solvents at room temperature. The photosensitivity of the polymer was investigated in various solvents in the presence and absence of triplet photosensitizers. The effect of the different solvents nature and concentration on the rate of photocrosslinking of the polymer were also examined for using the polymer as negative photoresist materials.     

Synthesis,Structure and Characterization of Three Metal Molybdate Hydrates: Fe(H2O)2(MoO4)2·H3O,NaCo2(MoO4)2(H3O2)and Mn2(MoO4)3·2H3O

Three metal molybdate hydrates,Fe(H2O)2(MoO4)2·H3O(FeMo),NaCo2(MoO4)2(H3O2)(CoMo)and Mn2(MoO4)3·2H3O(MnMo),were synthesized by the mixed-solvent-thermal methods and characterized by singlecrystal X-ray...     

Synthesis and physicochemical properties of [{Cd(?-C6H11NO)5}2Cr(NCS)6][Cd(?-C6H11NO)4Cr(NCS)6]

A new complex [{Cd(?-Cpl)₅}₂Cr(NCS)₆][Cd(?-Cpl)₄Cr(NCS)₆] was synthesized, and its crystal structure was solved. The complex was studied by chemical analysis and IR spectroscopy.     

Synthesis and Antimicrobial Activity of 4‐Aryl‐5‐phenyl‐imino‐3‐(tetra‐O‐benzoyl‐β‐D‐glucopyranosylimino)‐1,2,4‐dithiazolidines (Hydrochlorides)

Abstract

Synthesis of 4‐aryl‐5‐phenylimino‐3‐(tetra‐O‐benzoyl‐β‐D‐glucopyranosylimino)‐1,2,4‐dithiazolidines (hydrochlorides) is described. These compounds were screened for their antibacterial and antifungal activity against Escherichia coli, Staphylococcus aureus, P. vulgaris, Pseudomonas, Bacillus, Salomonella sp., Aspergilus niger, and Fusarium. The identities of these new N‐glucosides have been established on the basis of usual chemical transformation IR, NMR, and mass spectral studies.