4-(5-aryl-2-oxazolyl)phthalic anhydrides

4-(5-Aryl-2-oxazolyl)-substituted phthalic anhydrides were synthesized from 4-chloroformylphthalic anhydride and various -aminomethyl aryl ketones. The spectral-luminescence properties of solutions of the products in toluene and 5% NaOH solution were investigated. It is shown that the introduction of substituents with different electronic natures in the 5-phenyl ring of 4-(5-phenyl-2-oxazolyl) phthalic anhydride has a significant effect on the spectral-luminescence characteristics of the synthesized compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 35–37, January, 1979.     

Synthesis and luminescence properties of anhydrides and N-phenylimides of substituted 4-(5-phenyl-2-oxazolyl)-naphthalic acids

Anhydrides and N-phenylimides of 4-(5-phenyl-2-oxazolyl)naphthalic acids with various substituents in the para position of the phenyl ring were synthesized. Electron-donor substituents, particularly the dimethylamino group, induce an appreciable long-wave shift of the absorption maxima and the luminescence due to their interaction with the carbonyl group of the peri-anhydride grouping. A large Stokesian shift and a high photoluminescence quantum yield are characteristic for the dimethylamino-substituted anhydrides.     

2-(5-甲基-2-苯基-噁唑基)乙醇的合成

2-(5-甲基-2-苯基-噁唑基)乙醇的合成;Dakin-West反应;还原     

Anhydrides and phenylimides of 4-(5-aryl-2-oxazolyl)naphthalic acids

A number of 4-(5-aryl-2-oxazolyl)naphthalic anhydrides were obtained by condensation of 4-chloroformylnaphthalic anhydride with -aminomethyl aryl ketones and subsequent cyclization of the resulting amides; N-phenylimides were obtained from the anhydrides by reaction with aniline. The relationship between the structures of the substances obtained and their UV and luminescence spectra was investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1331–1333, October, 1973.     

4-(5-aryl-2-oxazolyl)benzenesulfonic acid derivatives containing a dimethylamino group

Condensation of 4-chlorosulfonyl- and 4-fluorosulfonyl-benzoyl chlorides with p-dimethylamino--aminoacetophenone followed by cyclodehydration of the resulting amides leads to the formation of 4-(5-dimethylaminophenyl-2-oxazolyl)benzenesulfonyl halides, and the corresponding sulfonic ester, sulfomorpholide, sulfonamide, and sodium salt are synthesized from them. The spectral and luminescence properties of the compounds synthesized have been studied in toluene, ethanol, and DMF. The ability of the sulfonyl group to transmit the electronic effects of the substituents on it to the overall molecular -electron system of 2,5-diaryloxazole has been demonstrated. Salvation fluorochromia has been detected in polar solvents. In some of the compounds studied the Stokes shift exceeds 200 nm.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 234–237, February, 1993.     

4-(5-Methoxy-2-oxazolyl)naphthalic anhydride and products of its condensation with aromatic amines

4-(5-Methyl-2-oxoazolyl)naphthalic anhydride was synthesized by condensation of 4-chloroformylnaphthalic anhydride with aminoacetone and subsequent cyclization of the resulting amide. Luminescing methyl-substituted N-phenylnaphthalimide and 1,8-naphthoylene-1,2-benzimidazple were obtained by condensation of this product with aniline and o-phenylenediamine, respectively. The relationship between the structures of the products and their electronic absorption and luminescence spectra was investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 883–885, July, 1976.     

The behavior of 1-(5-oxazolyl)-1-alkylidenes and 1-(5-isoxazolyl)-1-alkylidenes

Capture, rearrangement and/or fragmentation of 1-(5-oxazolyl)-1-alkylidenes and 1-(5-isoxazolyl)-1-alkylidenes are described.     

Synthesis and luminescence properties of 4-(2-methyl-5-oxazolyl)naphthalic anhydride and the products of its condensation with aromatic amines

4-(2-Methyl-5-oxazolyl)naphthalic anhydridewas synthesized by heating -aminomethyl 5-acenaphthyl ketone hydrochloride with acetic anhydride and subsequent oxidation of the resulting 2-methy1-5-(5-acenaphthyl)oxazole. 4-(2-Methyl-5-oxazolyl)-naphthalic acid phenylimide and 4(3)-(2-methyl-5-oxazolyl)-7-oxo-7H-benzimidazo-[1,2-b]benzo[de]isoquinoline were obtained by condensation of 4-(2-methy1-5-oxazo-lyl)naphthalic anhydride with aniline and o-phenylenediamine. The coincidence of the directions of polarization of the C=N bond of the oxazole ring and the electronic shifts in the system of the anhydride and phenylimide molecules leads to an increase in the quantum luminescence yield.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1613–1615, December, 1977.     

4-Arylvinyl-2,6-di(pyridin-2-yl)pyrimidines: synthesis and optical properties

A series of 4-arylvinyl-2,6-di(pyridin-2-yl)pyrimidines have been efficiently prepared by a double cross-coupling reaction between 2,4-dichloro-6-methylpyrimidine and 2-(tributylstannyl)pyridine, followed by aldol condensation with the appropriate aromatic aldehyde substituted with electron-donating, electron-withdrawing, dendritic, or water-soluble groups. The effect of different protic and aprotic solvents on the optical absorption and emission properties of these systems was studied. Compounds with electron-donating groups display strong emission solvatochromism, suggesting the formation of an intramolecular charge-separated emitting state. The solvatochromic behavior depends not only on the solvent polarity but also on the hydrogen bonding parameters of the solvent. The effect of protonation was also studied, and the abilities of some of these molecules to function as colorimetric and luminescent pH sensors were demonstrated with dramatic color changes and luminescence switching upon the introduction of acid.     

2-(4-Cyanophenyl)-5-aryloxazoles

2-(4-Cyanophenyl)-5-aryloxazoles have been obtained by dyhydration of 4-(5-aryloxazolyl-2)benzamides with thionyl chloride in DMFA, then the spectral and luminescent properties of the former have been investigated. Introduction of the cyano group into the 2-phenyl radical of 2,5-diphenyloxazole leads to significant bathochromic and bathofluoric effects.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1265–1266, September, 1986.     

Mesomorphic properties of 2-acyloxy5-(4-alkoxyphenylazo)tropones, 2-acyloxy-5-(4-alkylphenylazo)tropones,and 2-acyloxy-5-(4-alkoxycarbonylphenylazo)tropones

Three series of mesomorphic 2-acyloxy-5-phenylazotropones with alkoxy, alkyl, and alkoxycarbonyl groups at C-4 on the phenyl ring were prepared. It was known that the corresponding 5-phenylazotropolone derivatives and their methyl ethers were not mesomorphic. 2-Acetyl-5-(4-hexyloxyphenylazo)tropone, however, shows a monotropic smectic A phase. Even an acetyl group is therefore able to induce a mesophase. The effects of terminal substitution of the tropone ring by groups such as alkoxy, alkoxycarbonyl, and alkyl on the clearing points are discussed.     

Mesomorphic properties of 2-acyloxy5-(4-alkoxyphenylazo)tropones, 2-acyloxy-5-(4-alkylphenylazo)tropones, and 2-acyloxy-5-(4-alkoxycarbonylphenylazo)tropones

Three series of mesomorphic 2-acyloxy-5-phenylazotropones with alkoxy, alkyl, and alkoxycarbonyl groups at C-4 on the phenyl ring were prepared. It was known that the corresponding 5-phenylazotropolone derivatives and their methyl ethers were not mesomorphic. 2-Acetyl-5-(4-hexyloxyphenylazo)tropone, however, shows a monotropic smectic A phase. Even an acetyl group is therefore able to induce a mesophase. The effects of terminal substitution of the tropone ring by groups such as alkoxy, alkoxycarbonyl, and alkyl on the clearing points are discussed.     

Synthesis and spectral-luminescence properties of 4,4′-di(2-oxazolyl)-stilbenes and 4,4′-di(2-oxazolyl)tolans

A new method is proposed for the synthesis of 4,4-di(2-oxazolyl)stilbenes and 4,4-di(2-oxazolyl) tolans by condensation of oxazolyl-substituted benzyl bromides or benzal dibromides under the influence of strong bases (KOH, potassium tertbutoxide) in dipolar aprotic solvents [dimethylformamide (DMF) and dimethyl sulfoxide (DMSO)]. The synthesized compounds luminesce intensely over the spectral range 386–492 nm.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 463–467, April, 1981.     

Efficient and beta-Stereoselective Synthesis of 4(5)-(beta-D-Ribofuranosyl)- and 4(5)-(2-Deoxyribofuranosyl)imidazoles(1)

A synthetic route to 4(5)-(beta-D-ribofuranosyl)imidazole (1), starting from 2,3,5-tri-O-benzyl-D-ribose (5), was developed via a Mitsunobu cyclization. Reaction of 5 with the lithium salt of bis-protected imidazole afforded the corresponding 5-ribosylimidazole 7RS. Hydrolysis of 7RS gave a 1:1 mixture of diol isomers 8R and 8S having an unsubstituted imidazole. Mitsunobu cyclization of the mixture 8RS using N,N,N',N'-tetramethylazodicarboxamide and Bu(3)P exclusively afforded benzylated beta-ribofuranosyl imidazole 9beta in 92% yield, accompanied by alpha-anomer 9alpha, in a ratio of 26.3:1. The configuration of 9beta was established by X-ray crystallography of ethoxycarbonyl derivative 10beta. Reductive debenzylation of 9beta over Pd/C was carried out, and the synthesis of 1 was attained from starting 5 in four steps and 87% overall yield. This synthetic methodology was extended to the synthesis of 4(5)-(2-deoxy-beta-D-ribofuranosyl)imidazole (2). Mitsunobu cyclization of a 1:1 mixture of the corresponding diol isomers 14RS produced 15beta and 15alpha in a ratio of 5.4:1. The synthesis of 2 was attained in a 59% overall yield from the starting 3,5-di-O-benzyl-2-deoxy-D-ribose (12). beta-Stereoselective glycosylation in the key step is discussed and explained by intramolecular hydrogen bonding between an NH in the imidazole and the oxygen functional group in the sugar moiety.     

Synthesis of 2-(4-cyanophenyl)-5-(4-n-alkyl- and alkoxyphenyl) pyridines

New liquid-crystalline 2-(4-cyanophenyl)-5-(4-alkyl- and alkoxyphenyl)pyridines were obtained by condensation of 1-dimethylamino-3-dimethylimmonia-2-(4-alkyl- or alkoxyphenyl)-1-propene perchlorates with 4-cyanoacetophenone and subsequent conversion of the 1-dimethylamino-2-(p-alkyl- or alkoxyphenyl)-4-(p-cyanobenzoyl)-1,3-butadienes to 5-(4-alkyl- or alkoxyphenyl)-2-(4-cyanophenyl)pyrylium perchlorates and refluxing of the latter with ammonium acetate in acetic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1392–1394, October, 1985.     

Syntheses and Structural Characterization of 1-（4-Phenyl-2-thiazolyl）-3-（4-methylphenyl）-5-（2-furyl）-4,5-dihydro-（1H）-pyrazole and 1-（4-（4-Fluoro）phenyl-2-thiazolyl）-3-（4-methyl-phenyl）-5-（2-furyl）-4,5-dihydro-（1H）-pyrazole

The title compounds were synthesized and characterized by IR,1H-NMR,Mass and elementary analysis and single-crystal X-ray diffraction.In 1a,intermolecular C-H…π interactions produce a three-dimensional network.In 1b,intermolecular C-H…O hydrogen bonds generate an R22(22) ring.The hydrogen bonding is supported by C-H…π interactions.