An approach to the synthesis of chemically modified bisazocalix[4]arenes and their extraction properties

Bisazocalix[4]arenes [N,N′-bis(5-azo-25,26,27-tribenzoyloxy-28-hydroxycalix[4]arene)benzene (1), N,N′-bis(5-azo-25,26,27-tribenzoyloxy-28-hydroxycalix[4]arene)biphenyl (2) and N,N′-bis(5-azo-25,26,27-tribenzoyloxy-28-hydroxycalix[4]arene)-2,2′-dinitro biphenyl (3)] have been synthesized from 25,26,27-tribenzoyloxy-28-hydroxycalix[4]arene by diazocoupling with the corresponding aromatic diamines (p-phenylenediamine, 4,4′-diamino biphenyl and 4,4′-diamino-2,2′-dinitrobiphenyl). Extraction studies of bisazocalix[4]arenes 1, 2, and 3 show no difference in their extraction behavior and selectivity, whereas azocalix[4]arenes are a poor extractant for heavy metal cations. The absorption spectra of the prepared bisazocalix[4]arenes are discussed, both the effect of varying pH and solvent upon the absorption ability of bisazocalix[4]arenes.     

Reactivities of novel [hydroxy(tosyloxy)iodo]arenes and [hydroxy(phosphoryloxy)iodo]arenes for alpha-tosyloxylation and alpha-phosphoryloxylation of ketones

Novel [hydroxy(tosyloxy)iodo]arenes bearing 2-thienyl, 3-thienyl, N-tosyl-4-pyrazolyl, 3-trifluoromethylphenyl, and 3,5-bis(trifluoromethy)phenyl as an aromatic group, and [hydroxy(phosphoryloxy)iodo]arenes bearing N-tosyl-4-pyrazolyl, 3-trifluoromethylphenyl, and 3,5-bis(trifluoromethy)phenyl as an aromatic group, were prepared. alpha-Tosyloxylation and alpha-phosphoryloxylation of ketones with these compounds were carried out, respectively. Their reactivities were compared with that of the parent [hydroxy(tosyloxy)iodo]benzene and [hydroxy(phosphoryloxy)iodo]benzene, respectively, and consequently [hydroxy(tosyloxy)iodo]arenes and [hydroxy(phosphoryloxy)iodo]arenes bearing 3-trifluoromethylphenyl and 3,5-bis(trifluoromethy)phenyl as an aromatic group showed the best reactivity. These new compounds can be used as powerful alpha-tosyloxylation and alpha-phosphoryloxylation reagents, instead of the parent [hydroxy(tosyloxy)iodo]benzene and [hydroxy(phosphoryloxy)iodo]benzene.     

Preparations and properties of polymers containing 3,4-bis[(2,4,6-tri-t-butylphenyl)phosphinidene]-1,2-di(2-thienyl)cyclobutene moieties

Reaction of 1,8-bis[5-{(2,4,6-tri-t-butylphenyl)phosphinoethynyl}-2-thienyl]octane with butyllithium followed by treatment with 1,2-dibromoethane afforded a new polymer containing 3,4-bis[(2,4,6-tri-t-butylphenyl)phosphinidene]-1,2-di(2-thienyl)cyclobutene units. The polymer was allowed to react with bis(benzonitrile)dichloropalladium to give the polymer complex. A Sonogashira coupling reaction between ethynyltrimethylsilane and 4-bromonitrobenzene proceeded in DMF at 100 °C to give 4-nitro(trimethylsilylethynyl)benzene in the presence of the polymer complex, CuI, and triethylamine.     

Tris[bis(trimethysilyl)amido]zinkate von Lithium und Calcium

Tris[bis(trimethylsilyl)amido]zincates of Lithium and Calcium Calcium-bis[bis(trimethylsilyl)amide] and Bis[bis(trimethylsilyl)amido]zinc yield in 1,2-dimethoxyethane quantitatively Calcium-bis{tris[bis(trimethylsilyl)- amido]zincate} · 3DME. When THF is chosen as a solvent, the two reactants and the zincate form a temperature-independent equilibrium, whereas in benzene no reaction occurs. The tris[bis(trimethylsilyl)amido]zincate anion displays characteristic ¹³C{¹H) and ²⁹Si{¹H] chemical shifts of 7 and ?8 ppm, respectively; the nature of the solvent, the cation and the complexating ligands don't influence the IR nor NMR data of the zincate anion and thus verify that [Ca(DME)₃]²⁺ and {Zn[N(SiMe_{3 2}]₃}^? appear as solvent separated ions, which is also confirmed by their insolubility in hydrocarbons.     

Efficient synthesis of 3,3′,5,5′-tetra(p-X-phenylethynyl)biphenyl (X: NMe2; OMe) by homocoupling of 1-bromo-3,5-di(p-X-phenylethynyl)benzene or by heterocoupling of 3,3′,5,5′-tetraethynylbiphenyl with p-X-phenylbromobenzene with nickel or palladium complexes, respectively

The conjugated 3,3′,5,5′-tetra(p-X-phenylethynyl)biphenyl derivatives were efficiently obtained by homocoupling of 1-bromo-3,5-di(p-X-phenylethynyl)benzene mediated by zero-valent nickel complexes.The 1-bromo-3,5-di(p-X-phenylethynyl)benzene was previously prepared by heterocoupling between 1-bromo-3,5-di(ethynyl)benzene and p-X-iodobenzene (X: NMe₂; OMe) catalysed by the palladium/copper system in good yield. The necessary 1-bromo-3,5-di(ethynyl)benzene was obtained by heterocoupling between 1,3,5-tribromobenzene and 2-methyl-3-butyn-2-ol catalysed by palladium and successive treatment with sodium hydroxide in dry toluene, in good yield.The same 3,3′,5,5′-tetra(p-X-phenylethynyl)biphenyl (X: NMe₂; OMe) derivatives were alternatively synthesised in highest yield by heterocoupling between 3,3′,5,5′-tetra(ethynyl)biphenyl and p-X-bromobenzene (X: NMe₂; OMe) catalysed by palladium in excellent yields. Previously, 3,3′,5,5′-tetra(ethynyl)biphenyl was obtained in practically quantitative yield by homocoupling of 1-bromo-3,5-di[4-(2-methyl-3-butyn-2-ol)] benzene mediated by the zero-valent nickel complex to the 3,3′,5,5′-tetra{di[4-(2-methyl-3-butyn-2-ol)]}biphenyl followed the treatment with sodium hydroxide.     

Photochromic dihetarylethenes. 10. Photochromic 1,2-bis[2-(benzothiazol-2-yl)-3-thienyl]- and 1,2-bis[2-(benzothiazol-2-yl)benzothiophen-3-yl]ethenes

Dithienylethenes containing the thiophene rings with benzothiazolyl substituents in position 2 were synthesized. 1,2-Bis[2-(benzothiazol-2-yl)benzothiophen-3-yl]hexafluorocyclopentene and 1,2-bis[2,5-di(benzothiazol-2-yl)-3-thienyl]hexafluorocyclopentene possess photochromic properties. The open forms of 1,2-bis(2-benzothiazolylhetaryl)ethenes fluoresce, but introduction of the benzothiazole rings into dihetarylethenes significantly lowers the fatigue resistance of photochromes and favors thermal reversibility.     

Synthesis,nature of electronic transitions,and absorption spectra of the dye based on 4-(methyl-1-{2-[4-(1-methyl-2-oxo-1,2-dihydroquinolin-3-yl)phenyl]-2-oxoethyl}pyridinium bromide

The reaction of 3-(4-bromoacetylphenyl)-1-methylquinolin-2(1Н)-one with pyridine and 4-methylpyridine has afforded the corresponding pyridinium salts. Condensation of 4-methyl-1-{2-[4-(1-methyl-2-oxo-1,2-dihydroquinolin-3-yl)phenyl]-2-oxoethyl}pyridinium bromide with 4-dimethylaminobenzaldehyde has given a new biscyanine dye, 1-{1-[4-(1,2-dihydro-1-methyl-2-oxo-3-quinolinyl)benzoyl]-2-[4-(dimethylamino)-phenyl]ethynyl}-4-{2-[4-(dimethylamino)phenyl]ethynyl}pyridinium bromide. Its electronic spectrum has been analyzed, and quantum-chemical simulation of spatial and electronic structure of its possible isomers has been performed.     

Synthesis and some transformations of 2-(2-thienyl)-1(3)H-imidazo[4,5-f] quinoline

2-(2-Thienyl)-1(3)H-imidazo{cm[4,5-f]}quinoline was synthesized by the Weidenhagen reaction of quinoline-5,6-diamine with thiophene-2-carbaldehyde. Its methylation in the system KOH-DMSO gave isomeric 1-methyl-2-(2-thienyl)-1H- and 3-methyl-2-(2-thienyl)-3H-imidazo{cm[4,5-f]}quinolines, the latter being the major product. The 3-methyl derivative was subjected to electrophilic substitution reactions (bromination, nitration, formylation, acylation, sulfonation). Depending on the conditions, electrophilic attack was directed at the thiophene or quinoline fragment or both these.     

New viologen analogs: 1,4-bis[2-(pyridin-4-yl)ethenyl]benzene quaternary salts

Alkylation of 1,4-bis[2-(pyridin-4-yl)ethenyl]benzene with alkyl p-toluenesulfonates and dimethyl sulfate gave new viologen analogs, 1-alkyl-4-(2-{4-[2-(1-alkylpyridinium-4-yl)ethenyl]phenyl}ethenyl)-pyridinium bis(p-toluenesulfonates) and sulfate. Their derivatives with tetrafluoroborate and tetraphenylborate ions were also obtained. Spectral properties of the synthesized compounds were examined, and their structure was determined by X-ray analysis.     

Synthesis of bis(pyrrol-2-yl)arenes by Pd-catalyzed cross coupling

2-Borylpyrrole was prepared from 2-iodopyrrole almost quantitatively and then reacted with dihaloarenes under typical reaction conditions of Suzuki-Miyaura cross coupling to give bis(pyrrol-2-yl)arenes in good yields, while the cross coupling reaction of 2-iodopyrrole with 1,4-phenylenebisboronic acid was susceptible to oxidative self-coupling to produce 4,4′-bis(pyrrol-2-yl)biphenyl as a byproduct. These bis(pyrrol-2-yl)arenes showed strong fluorescence.     

Trimethylsilylated allyl complexes of nickel. The stabilized bis(pi-allyl)nickel complex [eta3-1,3-(SiMe3)2C3H3]2Ni and its mono(pi-allyl)NiX (X=Br, I) derivatives

Reaction of 2 equiv of K[1,3-(SiMe3)2C3H3] with NiBr2(dme) in THF at -78 degrees C produces the orange pi-allyl complex [1,3-(SiMe3)2C3H3]2Ni (1). Unlike the pyrophoric (C3H5)2Ni, the trimethylsilylated derivative only slowly decomposes in air (from hours to days). Both eclipsed (1a) and staggered (1b) conformations are found in solution; the eclipsed form irreversibly converts to the thermodynamically more stable staggered conformation when heated above 85 degrees C. Single-crystal X-ray structures obtained for both 1a and 1b confirm that the allyl ligands are bound in a trihapto manner to the metals and that trimethylsilyl substituents are in syn, anti arrangements. Density functional theory calculations performed on the bis(allyl)nickel complexes indicate that the substituents exert little effect on the basic metal-ligand geometries. Trimethylphosphine is converted to tetramethyltetraphosphane, (MeP)4, on reaction with 1. In toluene, 3-bromo-1,3-bis(trimethylsilyl)propene reacts with (COD)2Ni to produce the dimeric purple complex {[1,3-(SiMe3)2C3H3]NiBr}2 (2a). Both NMR and X-ray crystallographic data establish that the allyl ligands are staggered and that the trimethylsilyl substituents are in a syn, syn conformation. NMR data indicate that the reaction of one equivalent of 1 with Br2 in benzene produces an analogous complex (2b) with the allyl ligand substituents in a syn, anti configuration. When 1 equiv of 1 is treated with I2 in hexanes, the dark red dimeric complex {[1,3-(SiMe3)2C3H3]NiI}2 (3) is formed. Its X-ray crystal structure demonstrates that both eclipsed (3a) and staggered (3b) allyl conformation are present. The trimethylsilyl groups on the allyl ligands are in syn, anti arrangements in the two forms.     

Synthesis of 1,2-bis[2-methyl-5(3,4-difluorophenyl)-3-thienyl] perfluorocyclopentene

2-Methylthiophene (1) was treated at 0°C with liquid bromine to form 3,5-dibromo-2-methylthiophene (2) which reacted with tributyl borate to give 2-methyl-3-bromo-5-boronate thiophene (3) at −78°C. Treatment of 3 with 3,4-difluorobrombenzene gave 2-methyl-3-bromo-5-(3,4-difluorophenyl)thiophene (4). Finally, a novel photochromic dithienylethene compound, 1,2-bis [2-methyl-5(3,4-difluorophenyl)-3-thienyl]perfluorocyclopentene (DT-1), was synthesized by the reaction of 4 with perfluorocyclopentene at −78°C. The compound (DT-1) was characterized by IR, NMR, MS, elemental analysis and its photochromic behavior was also discussed. __________ Translated from Chinese Journal of Organic Chemistry, 2007, 27(10): 1282–1284 [译自: 有机化学]     

1,2-双[2-甲基-5-(3,4-二氟苯基)噻吩-3-基]全氟环戊烯的合成

在冰浴条件下, 2-甲基噻吩(1)与液溴反应生成3,5-二溴-2-甲基噻吩(2); 在－78 ℃条件下, 硼酸三丁酯加入2, 得到2-甲基-3-溴-5-硼酸基噻吩(3); 3,4-二氟溴苯与3反应得到2-甲基-3-溴-5-(3,4-二氟苯基)噻吩(4); 在－78 ℃下全氟环戊烯与4反应, 得到一种新的二芳基乙烯类光致变色化合物1,2-双[2-甲基-5-(3,4-二氟苯基)噻吩-3-基]全氟环戊烯(DT-1). 用IR, NMR, MS和元素分析确定了化合物DT-1的结构, 并对该化合物的光致变色特性进行了初步研究.     

Reactions of 5-[3-(trifluoromethyl)-phenyl]furan-2-carbaldehyde

The Knoevenagel condensations of 5-[3-(trifluoromethyl)phenyl]furan-2-carbaldehyde with seven compounds containing an active methyl or methylene group have been studied. The compounds used were: methyl 2-cyanoacetate, malononitrile, 2-furylacetonitrile, acetophenone, 2-thioxo-1,3-thiazolidin-4-one (rhodanine), 5,5-dimethylcyclohexane-1,3-dione (dimedone), and methyl 2-azidoacetate. The effect of microwave irradiation on the condensation reactions was studied and compared with “’classical”’ conditions. Thermolysis of methyl 2-azido-3-{5-[3-(trifluoromethyl)phenyl]-2-furyl}propenoate afforded methyl 2-[3-(trifluoromethyl)phenyl)]-4H-furo[3,2-b]pyrrole-5-carboxylate. (2E)-3-{ 5-[3-(Trifluoromethyl)phenyl]-2-furyl}propenoic acid was converted to the corresponding azide, which was cyclized on heating into 2-[3-(trifluoromethyl)phenyl)]-4,5-dihydrofuro[3,2-c]pyridin-4-one. The latter after successive action of POCl₃ and NH₂NH₂-Pd/C gave 2-[3-(trifluoromethyl)-phenyl]furo[3,2-c]pyridine. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 825–831, June, 2006.     

Synthesis, crystal structure and characterization of photochromic 1,2-bis{2-ethyl-5-[2-(1,3-dioxolane)]-3-thienyl}perfluorocyclopentene

A novel photochromic diarylethene, 1,2-bis{2-ethyl-5-[2-(1,3-dioxolane)]-3-thienyl}perfluorocyclopentene (BEDTP), was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. Its photochromic and fluorescent properties were also investigated. The results showed that this compound exhibited reversible photochromism, changing from colorless to magenta after irradiation with UV light both in solution and in the crystalline phase. In hexane solution, the open-ring isomer of BEDTP exhibited relatively strong fluorescence at 400 nm when excited at 282 nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 254 nm light and its closed-ring isomer showed almost no fluorescence.     

Some aromatic polyimides based on diamines containing hydrazo group and ether linkages

Three new hydrazo-bridged diamines, 4,4′-bis [4-(4-aminophenyloxy) phenylhydrazyl] biphenyl (BPD-2), 4,4′-bis [4-(4-aminophenyloxy) phenylhydrazyl] biphenyl ether (SPD-2) and 4,4-bis [4-(4-aminophenyloxy) phenyl] hydrazine (APD-2), were synthesized by the reduction of three azo-diols, 4,4′-bis (4-azo-1-hydroxyphenyl) biphenyl (BPD), 4,4′-bis (4-azo-1-hydroxyphenyl) biphenyl ether (SPD) and azo-4-hydroxybenzene (APD), and polymerized with pyromellitic dianhydride (PM), 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BP) and 3,4,9,10-perylenetetracarboxylic acid dianhydride (PR) either by one-step solution polymerization or by two-step procedure which includes ring-opening polyaddition to give poly(amic acid) followed by cyclic dehydration to polyimide. The monomers and polyimides were characterized by their elemental analyses, FTIR and ¹H NMR spectroscopy. Glass transition temperatures of the polymers are quite high (175-310 °C), characteristic of polyimides. The decomposition temperatures for 10% weight loss fall in the range of 280-575 °C in nitrogen. Activation energies of pyrolysis for each of the polymers calculated from Horowitz and Metzger's method are also high (52.54-95.28 kJ mol⁻¹). The inherent viscosities of the polyimides at a concentration of 0.5 g/dl in DMF range from 0.94 to 1.93 dl/g.     

Cyclization reactions of 2-(2-chloro-4-nitrophenylsulfonyl)-1-(2-thienyl)ethanone

A new sulfonyl group-containing heterocyclic compound 2-(2-chloro-4-nitrophenylsulfonyl)-1-(2-thienyl)ethanone 2 was prepared from the corresponding sulfide 2-(2-chloro-4-nitrophenylthio)-1-(2-thienyl)ethanone 1 . Two different cyclization reactions of the compound 2 were discussed. In contrast to the tandem alkylation-cyclization process [1], another cyclic procedure was described. In the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene as a base and dimethylformamide as a solvent, compound 2 was treated with ethyl acrylate or methyl methacrylate at 50–55° to give the 1,4-benzoxathiin 4,4-dioxide 5 or 6 respectively via a tandem Michael conjugate addition-cyclization process.     

Bromine-induced cyclization of 1-acyl-3-(3-thienyl)-2-thioureas to 2-acylaminothieno[3,2-d]thiazoles

Three different 1-acyl-3-(3-thienyl)-2-thioureas were cyclized to 2-acylaminothieno[3,2-d]thiazoles with bromine in acetic acid whereas the corresponding 2-thienylthiourea derivatives were brominated under the same reaction conditions. The parent thieno[3,2-d]thiazole was prepared by acid hydrolysis and deamination of 2-benzoylaminothieno[3,2-d]thiazole. This new heterocyclic compound was nitrated and brominated in the 5-position.     

Synthesis and some transformations of methyl [4-(oxoacetyl)phenyl]carbamate

The oxidation of methyl (4-acetylphenyl)carbamate with selenium dioxide in dioxane–water (30: 1) gave methyl [4-(oxoacetyl)phenyl]carbamate whose condensation with ethyl acetoacetate or diethyl malonate and hydrazine hydrate afforded ethyl 3-methyl-6-[4-(methoxycarbonylamino)phenyl]pyridazine-4-carboxylate and methyl {4-[5-(hydrazinecarbonyl)-6-oxo-1,6-dihydropyridazin-3-yl]phenyl}carbamate, respectively. The reaction of methyl [4-(oxoacetyl)phenyl]carbamate with o-phenylenediamine in dimethylformamide–ethanol on heating led to the formation of methyl [4-(quinoxalin-2-yl)phenyl]carbamate. Methyl {4-(5,7-dioxo- 4,4a,5,6,7,8-hexahydropyrimido[4,5-c]pyridazin-3-yl)phenyl}carbamate and methyl {4-(5-oxo-7-sulfanylidene- 4,4a,5,6,7,8-hexahydropyrimido[4,5-c]pyridazin-3-yl)phenyl}carbamate were synthesized by reactions of methyl [4-(oxoacetyl)phenyl]carbamate with barbituric and thiobarbituric acids, respectively, and hydrazine hydrate in the presence of zirconyl chloride octahydrate at room temperature.     

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.