The synthesis of azole derivatives from 3-[(4-methylphenyl)amino]propanehydrazide and its N′-phenylcarbamoyl derivatives, and their antibacterial activity

Abstract  

5-[2-[(4-Methylphenyl)amino]ethyl]-1,3,4-oxadiazol-2(3H)-thione, 5-[2-[(4-methylphenyl)amino]ethyl]-1,3,4-oxadiazol-2(3H)-one, N-(2,5-dimethyl-1H-pyrrol-1-yl)-3-[(4-methylphenyl)amino]propanamide, and a series of N-[(phenylcarbamoyl)amino]-3-[(4-methylphenyl)amino]propanamides and 3-[(4-methylphenyl)(phenylcarbamoyl)amino]-N-[(phenylcarbamoyl)amino]propanamides, and their thio analogues were synthesized from 3-[(4-methylphenyl)amino]propanehydrazide. 1,3,4-Oxadiazole-2(3H)-thione was converted to 4-amino-2,4-dihydro-5-[2-[(4-methylphenyl)amino]ethyl]-3H-1,2,4-triazole-3-thione, whereas cyclization of N′-phenylcarbamoyl derivatives provided thiazole, oxadiazoles, and thiadiazole, as well as triazole derivatives. Two of the synthesized compounds exhibited good antibacterial activity against Rhizobium radiobacter.     

Synthesis of 1,2,3,4-tetrahydro-5H-[1]benzopyrano[3,4-c]pyridin-5-ones. I. 3-unsubstituted compounds

Synthesis of 1,2,3,4-tetrahydro-5H-[1]benzopyrano[3,4-c]pyridin-5-ones via a Pechmann condensation of 3-carbethoxy-1-methyl-4-piperidone with various phenols is described. The limitations of this method are discussed. Synthesis of the parent ring system 3a via reduction of 1,2,3,4-tetrahydro-3-(phenylmethyl)-8-[(1-phenyl-1H-tetrazol-5-yl)oxy]-5H-[1]benzopyrano[3,4-c]pyridin-5-one ( 5 ) is also described.     

The reactions of 4-dicyanomethylene-2-phenyl-4H-1-benzopyran and some benzologs with nucleophiles

4-Dicyanomethylene-2-phenyl-4H-1-benzopyran (1) reacts with primary amines under mild conditions to give 4-imino-3-alkyl-5-alkylimino-2-phenyl-3,4-dihydro-5H-[1]benzopyrano[3,4-c]-pyridine derivatives which, in turn, are hydrolyzed with acid to 4-imino-3-alkyl-2-phenyl-3,4-dihydro-5H-[1]benzopyrano[3,4-c]pyridin-5-ones. When more vigorous conditions are employed for the reactions of 1 with primary amines, Dimroth rearrangements take place and the products are derivatives of 4-alkyl- (or aryl)amino-5-alkyl- (or aryl)imino-2-phenyl-5H-[1]benzopyrano-[3,4-c]pyridine. The latter compounds are hydrolyzed by acid to the corresponding 5-pyridone derivatives. The reaction of 1 with piperidine gives 2-phenyl-4-piperidyl-5H-[1]benzopyrano-[3,4-c]pyridin-5-one. Sodium methoxide reacts with 1 to give 3-cyano-2-methoxy-4-(2-hydroxyphenyl)-6-phenylpyridine. Two benzologs of 1 have been allowed to react with primary and secondary amines and the products are analogous to those obtained from 1 .     

Synthesis,anti-inflammatory and analgesic activity of 2-[4-(substituted benzylideneamino)-5-(substituted phenoxymethyl)-4H-1,2,4-triazol-3-yl thio] acetic acid derivatives

The title compounds 3a–l have been synthesized by the reaction of thiocarbohydrazide with substituted phenoxy acetic acid to obtained substituted 1,2,4-triazoles (1). Compound 1 was treated with various substituted aromatic aldehydes which results in 4-(substituted benzylideneamino)-5-(substituted phenoxymethyl)-2H-1,2,4-triazol-3(4H)-thiones (2a–g), further 2a–g is converted to 2-[4-(substituted benzylideneamino)-5-(substituted phenoxymethyl)-4H-1,2,4-triazol-3-yl thio] acetic acid (3a–l) derivatives by the reaction with chloroacetic acid. All the newly synthesized compounds were evaluated for in vivo anti-inflammatory and analgesic activities. Among the series 2-[4-(2,4-dichlorobenzylideneamino)-5-(phenoxymethyl)-4H-1,2,4-triazol-3-yl thio] acetic acid (3d), 2-[4-(4-dichlorobenzylideneamino)-5-(phenoxymethyl)-4H-1,2,4-triazol-3-yl thio] acetic acid (3e), 2-[4-(2,4-dichlorobenzylideneamino)-5-[(2,4-dichlorophenoxy)methyl]-4H-1,2,4-triazol-3-yl thio] acetic acid (3j) and 2-[5-[(2,4-dichlorophenoxy)methyl)]-4-(4-chlorobenzylideneamino)-4H-1,2,4-triazol-3-yl thio] acetic acid (3k) showed significant anti-inflammatory activity with P < 0.001 (63.4%, 62.0%, 64.1% and 62.5% edema inhibition, respectively), as compared to the standard drug diclofenac (67.0%) after third hour respectively and also compounds 3j, 3k exhibited significant analgesic activity with P < 0.001 (55.9% and 54.9% protection, respectively) and less ulcerogenic activity as compared with standard drug aspirin (57.8%).     

1,6-Eliminationsreaktionen an Spirocoleonon; Charakterisierung der ersten Spiro[(methylcyclopropan)-phenanthren]-1,3-dion-Derivate

Preparation of the First Spiro[(methylcyclopropan)-phenanthrene]-1,3-dione Derivatives by 1,6-Elimination Reactions of Spirocoleons Spirocoleons, e.g. coleon J ( 1 ), on treatment with 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) in aprotic solvents, undergo enolization followed by a rapid 1,6-elimination with formation of the hitherto unknown 2-methyl-spiro[cyclopropane-1,2′(1′H)-phenanthrene]-1′,3′(4′bH)-dione system, e.g. 3 . In protic solvents, base-catalyzed solvolysis of the spirocyclopropane predominates.     

Ring transformation of 6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine. IV (1). Reduction and reaction of 5a-acetyl-6a-ethoxycarbonyl-5a,6a-dihydro-6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine-3-carbonitriles with primary amines

The reaction of 5a-acetyl-6-ethoxycarbonyl-5a,6a-dihydro-6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine-3-carbonitrile ( 1a ) with benzylamine gave ethyl l-benzyl-5-cyano-8a,9-dihydro-2-methyl-1H-pyrrolo[3,4-e]-pyrazolo[1,5-a]pyrimidine-8a-carboxylate ( 2a ), in addition to 5-acetyl-3-benzylamino-1-(4-cyanopyrazol-3-yl)- 2-pyridone ( 3 ). Reaction of 1a with aniline gave ethyl 6-acetyl-8-anilino-3-cyano-7,8-dihydro-4H-pyrazolo-[1,5-a][1,3]diazepine-8-carboxylate ( 4 ), in addition to ethyl 3-cyano-7-methyl-6-pyrazolo[1,5-a]pyrimidine-acrylate ( 5 ). On the other hand, the same reactions of 1b with benzylamine or aniline gave 2b or 8b , respectively. Though catalytic hydrogenation of 1a over 5% palladium-carbon proceeded by ring fission of cyclopropane ring to give 9 , 1a (or 1b ) afforded 4,5-dihydro derivatives ( 13 or 15 ) by catalytic hydrogenation over platinum oxide. The reactivity of 5-methoxy-4,5,5a,6a-tetrahydro-6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine ( 16 ), which are related analogs of 1a,b , is also described.     

Synthesis of <Emphasis Type="Italic">O</Emphasis>-[2-[<Superscript>18</Superscript>F]fluoro-3-(2-nitro-1<Emphasis Type="Italic">H</Emphasis>-imidazole-1-yl)propyl]tyrosine ([<Superscript>18</Superscript>F]FNT]) as a new class of tracer for imaging hypoxia

For detection of hypoxic tumor tissue, all radiotracers synthesized until now, are based on the concept that cellular uptake is being controlled by diffusion. As a new approach, we chose the concept to have the tracer hypothetically transported into the cells by well known carrier systems like the amino acid transporters. For this purpose, radiosynthesis of O-[2-[¹⁸F]fluoro-3-(2-nitro-1H-imidazole-1yl)propyl]tyrosine ([¹⁸F]FNT]) was carried out from methyl 2-(benzyloxycarbonyl)-3-(4-3-(2-nitro-1H-imidazol-1-yl)-2-(tosyloxy)propoxy) phenyl)propanoate via no-carrier-added nucleophilic aliphatic substitution. After labelling, 81 ± 0.9% of labelled intermediate i.e. methyl 2-(benzyloxycarbonyl)-3-(4-(2-[¹⁸F]fluoro-3-(2-nitro-1H-imidazole-1-yl)propoxy) phenyl)propanoate was obtained at 140 °C. At the end of radiosynthesis, [¹⁸F]FNT was obtained in an overall radiochemical yield of 40 ± 0.9% (not decay corrected) within 90 min in a radiochemical purity of >98% in a formulation ready for application in the clinical studies for PET imaging of hypoxia.     

Studies in negative ion mass spectrometry. VIII—Electron capture by some monomeric and dimeric η5—cylcopentadienyl transition metal carbonyls

The negative ion mass spectra of a series of monomeric and dimeric η⁵-cyclopentadienyl transition metal carbonyls have been examined. The base peak in the case of the monomeric compounds (η⁵-C₅H₅)V(CO)₄, (η⁵-C₅H₅)Mn(CO)₃ and (η⁵-CH₃C₅H₄)Mn(CO)₃ arises from a reductive decarbonylation of the parent molecule—the resulting radical anion [M–CO]^? is formally isoelectronic with the molecular cations [M]^? observed in the positive ion mass spectra of these compounds and subsequently undergoes successive decarbonylations to the ‘aromatic’ cyclopentadienyl anions. For the compound (η⁵-C₅H₅)Co(CO)₂, however, a molecular anion was observed as the base peak which has been formulated as [(η³-C₅H₅)Co(CO)₂]^? in the light of considerations based on the rare gas rule. As expected, the dimeric molecules [(η⁵-C₅H₅)M(CO)₃]₂ (where M = Cr or Mo) and [(η⁵-C₅H₅)Fe(CO)₂]₂ (and its methyl analogue) undergo reductive cleavage of their metal-metal bonds to give the anions [(η⁵-C₅H₅)M(CO)₃]^? and [(η⁵-C₅H₅)Fe(CO)₂]^? as the base peaks in their negative ion mass spectra. The dimeric nickel compound [(η⁵-C₅H₅)Ni(CO)]₂, however, reductively decarbonylates to the [M-CO]^? radical anion as its predominant fragmentation in the gas phase. Very low abundances of [(η⁵-C₅H₅)Fe(CO)₂] and [(η⁵-CH₃C₅H₄)Fe(CO)₂] were also observed.     

Studies in spiroheterocycles. Part XVII. synthesis of novel fluorine containing spiro[indole-pyranobenzopyran] and spiro[indenopyran-indole] derivatives

An elegant one-step synthesis of two novel spiro ring systems viz: spiro[3H-indole-3,4′-(2′-amino-3′-carbonitrile-[4′H]-pyrano[3,2-c]benzopyran)]-2,5′(1H)-dione8 and spiro[(2-amino-3-carbonitrile-indeno[1,2-b]pyran)-4(5H)>3′-[3H]indole]-2′,5(1′H)-diones in 80–85% yields is described. The spiro heterocycles were prepared by the reactions of fluorine containing 3-dicyanomethylene-2H-indol-2-ones with 4-hydroxy-2H-1-benzopyran-2-one and 1H-indene-1,3(2H)-dione respectively. The synthesized compounds have been characterized on the basis of elemental analyses, ir, pmr, ¹⁹F nmr and mass spectral data.     

Synthesis of 4-methylthio-2(1H)-pyridone derivatives using ketene dithioacetals

Reaction of various active methylene compounds with ketene dithioacetals, bis(methylthio)methylenemalononitrile (1a) and bis(methylthio)methylenecyanoacetamide (1b) gave the corresponding 3-cyano-4-methylthio-2(1H)-pyridone derivatives. The transformation of 4-methylthio-2-oxo-2H-pyran-3-carbonitrile in-to 4-methylthio-2(1H)-pyridone derivatives was also described.     

Pyridazines with heteroatom substituents in positions 3 and 5. 6. SN reactions in position 5 of 2-aryl-5-hydroxypyridazin-3(2H)-ones

The nucleophilic introduction of chloro- ( 2 ), azido- ( 4 ), (substituted) amino ( 3, 6 ), mercapto ( 10 ) and hydrazino-groups ( 13 ) into 2-aryl-5-hydroxypyridazin-3(2H)-ones [3] is described. The 5-aminopyridazin-3(2H)-one ( 6 ) also reacts with activated malonates 8 [4] to give pyrido[2,3-d]pyridazines 9 . Hydrazino compounds 13 can be treated with aldehydes to yield compounds 14 . Iodine can be introduced into position 4 of 5 -amino -(15 ) and 5-hydroxypyridazin-3(2H)-ones ( 17 ) by electrophilic substitution to afford compounds 18 .     

Synthesis and biological evaluation of 5-methyl-4-phenyl thiazole derivatives as anticancer agents

Abstract

New N-(5-methyl-4-phenylthiazol-2-yl)-2-(substituted thio)acetamides were synthesized and studied for their anticancer activity. The title compounds were procured by reacting 2-chloro-N-(5-methyl-4-phenylthiazol-2-yl)acetamide with some mercapto derivatives. The structural elucidation of the compounds was performed by ¹H-NMR, ¹³C-NMR and LC-MS/MS spectral data and elemental analyses. The synthesized compounds were investigated for their antitumor activities against A549 human lung adenocarcinoma cells and NIH/3T3 mouse embryoblast cell line for determining their selective cytotoxicity. 2-[(1-methyl-1H-tetrazol-5-yl)thio]-N-(5-methyl-4-phenylthiazol-2-yl)acetamide (4c) showed high selectivity, and whose IC₅₀ value was determined as 23.30?±?0.35?µM and >1000?µM against A549 human lung adenocarcinoma cells and NIH/3T3 mouse embryoblast cell lines, respectively. 2-[(1-Methyl-1H-imidazol-2-yl)thio]-N-(5-methyl-4-phenyl thiazol-2-yl)acetamide (4a) and 2-[(1-Methyl-1H-tetrazol-5-yl)thio]-N-(5-methyl-4-phenyl thiazol-2-yl)acetamide (4c) exhibited the highest apoptosis percentage among those tested, but not as high as the standard, cisplatin.     

[2 + 2] Photodimerization of the acenaphthylene ruthenium complex [(C5Me4CH2OMe)Ru(η6-C12H8)]+

The [2 + 2] photodimerization of the complex [(C₅Me₄CH₂OMe)Ru(η⁶-C₁₂H₈)]⁺ under visible-light irradiation leads to a mixture of the head-to-head heptacyclene products [(μ-η⁶: η⁶-C₂₄H₁₆)Ru₂(C₅Me₄CH₂OMe)₂]²⁺ (syn- and anti-) with the predominant formation of the syn-isomer; the structures of both isomers were established by X-ray diffraction analysis.     

Synthesis of spiropyrans and merocyanine dyes based on 1-benzothieno[3,2-<Emphasis Type="Italic">b</Emphasis>]pyrrole

A convenient method was developed for the synthesis of photochromic spiropyrans and merocyanine dyes of the 1-benzothieno[3,2-b]pyrroline series based on the conventional condensation of the analog of Fischer’s salt, viz., 1,2,3,3-tetramethyl-3H-[1]benzothieno-[3,2-b]pyrrolium triflate, with aromatic 2-hydroxyaldehydes. Unlike Fischer’s salt, benzothieno-pyrrolium salts readily undergo the [1,5]-sigmatropic rearrangement giving rise to 2H-[1]benzo-thieno[3,2-b]pyrrole derivatives. The latter compounds were used for the synthesis of the first representatives of the previously unknown spiro compounds and merocyanine dyes. The long-wavelength maxima of merocyanines of the 2H-benzothienopyrrole series are batho-chromically shifted by more than 100 nm with respect to the absorption maxima of the “classical” 3H-benzothienopyrrole analogs.     

Azoles and Azines: CXIX. Alkylation of 5,5'-(4-Nitrobenzylidene)bis(2-thiobarbituric) Acid and 5-(4-Nitrophenyl)-2,8-dithioxo-5,7,8,9-tetrahydro-2H-pyrano[2,3-d:6,5-d']dipyrimidine-4,6(1H,3H)-dione with Haloacetic Acids and Their Esters

5,5'-(4-Nitrobenzylidene)bis(2-thiobarbituric) acid and 5-(4-nitrophenyl)-2,8-dithioxo-5,7,8,9-tetrahydro-2H-pyrano[2,3-d:6,5-d']dipyrimidine-4,6(1H,3H)-dione, similar to unsubstituted 2-thiobarbituric acid, readily react with haloacetic acids and their esters to form regioselectively the S-alkylation products. The alternative routes fo 5,5'-(4-nitrobenzylidene)bis[(4-hydroxy-6-oxo-1,6-dihydropyrimidine-5,2-diyl)sulfanyl]diacetic acids, based on condensation of 4,6-dihydroxypyrimidin-2-ylthioacetic acid with carbonyl compounds followed by cyclodehydration to [(5-(4-nitrophenyl)-4,6-dioxo-3,5,6,7-tetrahydro-4H-pyrano[2,3-d:6,5-d']dipyrimidine-2,8-diyl)di(sulfanyl)]diacetic acid derivatives, are less efficient. Alkylation of 2-thiobarbituric acid with ethyl bromoacetate in ethanol in the presence of alkali yields 5-(2-oxo-2,5-dihydro-1,3-thiazol-4-yl)-2-thiobarbituric acid.     

1,2-Fused pyrimidines. III. Derivatives of 12H-pyrido[1′,2′:1,2]pyrimido[4,5-b]quinoline,a novel heterocyclic system

Reactivities of 2-amino-4H-pyrido[1,2-a]pyrimidin-4-ones and 4-amino-2H-pyrido[1,2-a]pyrimidin-2-ones, both N,N-dialkyl and (N-alkyl, N-phenyl)substituted, when treated with the N,N-dimethylformamide/phosphorus oxychloride Vilsmeier-Haack reagent XII were compared. Starting from 2-[(N-alkyl, N-phenyl)amino] compounds IXa,b , the expected XVIa,b and XVIIa,b were obtained, which are derivatives of 12H-pyrido[1′,2′:1,2]pyrimido[4,5-b]quinoline, a novel heterocyclic system. When 2-(phenylamino) compound IXc was used a mixture of 3-formylderivative XVIII and 12H-pyrido-[1′,2′:1,2]pyrimido[4,5-b]quinolin-12-one ( XIX ) resulted from the reaction. On the other hand, 2-(dialkylamino)-4H-pyrido[1,2-a]pyrimidin-4-ones IIIa-c plainly afforded high yields of 3-formylderivatives XIVa-c. In contrast, no significant reaction occurred when 4-(dialkylamino) and 4-[(N-alkyl,N-phenyl)amino] compounds IIa-c and VIIIa,b were treated with the reagent XII , under the same as well as more severe conditions. A clear difference in the nucleophilic reactivity of C-3 position between these two classes of isomers is pointed out by the above summarized results.     

Reaction of ethyl γ-bromo-β-methoxycrotonate with carbonyl compounds. Synthesis of 4-methoxy-6-substituted-5,6-dihydro-2H-pyran-2-ones and 3-substituted 3-pyrazolin-5-ones

Ethyl β-methoxycrotonate I reacts with substituted carbonyl compounds II in benzene to give 4-methoxy-6-substituted-5,6-dihydro-2H-pyran-2-ones III. The reaction of IIIa and j with hydrazine hydrate in ethanol leads to 3-[(1′-thienyl-1-hydroxy)methyl]-5-hydroxy-1H-pyrazole (IVa) and 3-[1′-styryl-1′-hydroxy)methyl]-5-hydroxy-1H-pyrazole (IVj) in good yields. The structure of the products were assigned and confirmed on the basis of their elemental analysis and the electronic absorption, infrared and nmr spectra.     

Synthesis and characterization of a cadmium(II)–organic supramolecular coordination compound based on the multifunctional 2‐amino‐5‐sulfobenzoic acid ligand

Much attention has been paid by chemists to the construction of supramolecular coordination compounds based on the multifunctional ligand 5‐sulfosalicylic acid (H₃SSA) due to the structural and biological interest of these compounds. However, no coordination compounds have been reported for the multifunctional amino‐substituted sulfobenzoate ligand 2‐amino‐5‐sulfobenzoic acid (H₂asba). We expected that H₂asba could be a suitable building block for the assembly of supramolecular networks due to its interesting structural characteristics. The reaction of cadmium(II) nitrate with H₂asba in the presence of the auxiliary flexible dipyridylamide ligand N,N′‐bis[(pyridin‐4‐yl)methyl]oxamide (4bpme) under ambient conditions formed a new mixed‐ligand coordination compound, namely bis(3‐amino‐4‐carboxybenzenesulfonato‐κO¹)diaquabis{N,N′‐bis[(pyridin‐4‐yl)methyl]oxamide‐κN}cadmium(II)–N,N′‐bis[(pyridin‐4‐yl)methyl]oxamide–water (1/1/4), [Cd(C₇H₆NO₅S)₂(C₁₄H₁₄N₄O₂)₂(H₂O)₂]·C₁₄H₁₄N₄O₂·4H₂O, (1), which was characterized by single‐crystal and powder X‐ray diffraction analysis (PXRD), FT–IR spectroscopy, thermogravimetric analysis (TG), and UV–Vis and photoluminescence spectroscopic analyses in the solid state. The central Cd^II atom in (1) occupies a special position on a centre of inversion and exhibits a slightly distorted octahedral geometry, being coordinated by two N atoms from two monodentate 4bpme ligands, four O atoms from two monodentate 4‐amino‐3‐carboxybenzenesulfonate (Hasba⁻) ligands and two coordinated water molecules. Interestingly, complex (1) further extends into a threefold polycatenated 0D→2D (0D is zero‐dimensional and 2D is two‐dimensional) interpenetrated supramolecular two‐dimensional (4,4) layer through intermolecular hydrogen bonding. The interlayer hydrogen bonding further links adjacent threefold polycatenated two‐dimensional layers into a three‐dimensional network. The optical properties of complex (1) indicate that it may be used as a potential indirect band gap semiconductor material. Complex (1) exhibits an irreversible dehydration–rehydration behaviour. The fluorescence properties have also been investigated in the solid state at room temperature.     

Four NiII complexes with the new cyclam–methylimidazole ligand 1‐[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane

Although it has not proved possible to crystallize the newly prepared cyclam–methylimidazole ligand 1‐[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane (L^Im1), the trans and cis isomers of an Ni^II complex, namely trans‐aqua{1‐[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane}nickel(II) bis(perchlorate) monohydrate, [Ni(C₁₅H₃₀N₆)(H₂O)](ClO₄)₂·H₂O, (1), and cis‐aqua{1‐[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane}nickel(II) bis(perchlorate), [Ni(C₁₅H₃₀N₆)(H₂O)](ClO₄)₂, (2), have been prepared and structurally characterized. At different stages of the crystallization and thermal treatment from which (1) and (2) were obtained, a further two compounds were isolated in crystalline form and their structures also analysed, namely trans‐{1‐[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane}(perchlorato)nickel(II) perchlorate, [Ni(ClO₄)(C₁₅H₃₀N₆)]ClO₄, (3), and cis‐{1,8‐bis[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane}nickel(II) bis(perchlorate) 0.24‐hydrate, [Ni(C₂₀H₃₆N₆)](ClO₄)₂·0.24H₂O, (4); the 1,8‐bis[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane ligand is a minor side product, probably formed in trace amounts in the synthesis of L^Im1. The configurations of the cyclam macrocycles in the complexes have been analysed and the structures are compared with analogues from the literature.     

链状双杂芳基乙烯化合物的合成与光化学性质研究

合成了1,n-双[4-[2-[2-(5-甲基苯并唑基)]乙烯基]苯氧基]烷烃(a:n=3;b:n=4;c:n=6)和2,2'-双[4-[2-[2-(5-甲基苯并唑基)]乙烯基]苯氧基]乙醚(d)4个新化合物.用元素分析、红外、紫外、核磁共振谱和质谱表征了其结构.用紫外吸收光谱跟踪研究了Ⅰa_Ⅰd在紫外灯照射下的变化,发现上述化合物在高压汞灯照射下可同时发生反顺异构化和[2+2]分子内光二聚两种反应,反顺异构化反应迅速可逆,而光二聚反应进行缓慢且不可逆.增加链长有助于提高分子内光二聚反应的速率.分子内光二聚反应不受空气中氧的影响的事实表明其是经激发单线态历程进行的.还发现分子内光二聚体在短波紫外光照射下容易进行逆[2+2]光解开环反应.上述化合物分子内光二聚和光解开环反应可以反复进行多次,表明该类化合物具有较高的光稳定性.