Synthesis of various camphor-based chiral pyridine derivatives

(+)-β-Hydroxymethylenecamphor 1 and enamines 2a-e were transformed into chiral camphor-based pyridine derivatives 3a-e via a tandem condensation reaction in good yields.     

Synthesis of pyrylium and pyridine derivatives of benzofuran

Acylation of benzo[b]-2-furyl acetone was used to synthesize 2,9-disubstituted benzofuro[3,2c] pyrylium perchlorates, which were converted in high yields to the corresponding benzofuro-[3,2-c]pyridines. The molecular diagram of the pyrylium cation is examined. The IR, UV, and NMR spectra of the synthesized compounds are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 450–456, April, 1973.     

Electronic absorption spectra of pyrylium and benzodihydrochromenylium salts

The electronic absorption spectra of benzodihydrochromenylium, tetrahydrochromenylium, and dichloropyrylium salts were studied for the first time. It was noticed that intramolecular charge transfer takes place mainly between the substituent at position 4 of the pyrylium ring and the π-system of the cation as a whole, while the bathochromic shift depends substantially on the geometry of the molecule. It was shown that the chlorine atoms have an effect on the form of the spectra when they are introduced into the ring of the pyrylium cation and into the aryl substituents. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1152–1159, August, 2008.     

Synthesis of new chiral fluorescent sensors and their applications in enantioselective discrimination

Five novel sensors (R,R)-3–6 and (S, S)-6 were synthesized and developed for enantioselective recognition of chiral compounds. Sensor 6 with two thiourea groups and steric π-conjugation frameworks could discriminate different chiral substrates, including acidic compounds, basic compounds, and neutral compounds. These results disclosed that the outstanding performance of enantioselective discrimination could be attributed to the thiourea group which acted as a hydrogen-bonding donor and the bulky steric moiety of the hosts which provided appropriate chiral environment. This result will be of great practical value in the designation of chiral sensors and high-throughput assay of chiral products.     

Synthesis of new chiral fluorescent sensors and their applications in enantioselective discrimination

New chiral fluorescent sensors derived from tetraphenylethylene and proline hydrazide were synthesized and applied in the chiral recognition of various chiral compounds, including unprotected amino acids, acidic compounds, chiral amines and even neutral alcohols. These results demonstrated that the excellent enantioselective response ability to various chiral substrates could be attributed to the –NH moieties of pyrrolidine ring and thiourea unit which acted as hydrogen-bonding donors. This result is of potential significance in enantiomeric discrimination and high-throughput analysis of the enantiomeric purity of chiral guests.     

Synthesis of pyridine and pyrimidine derivatives by reaction of pyrylium salts with ureas,thioureas, and isothioureas

2,4,6-Triphenylpyrylium perchlorate is converted to 2,4,6-triphenylpyridine in reactions with urea and N-acetyl- and N,N-dimethylureas, whereas it is converted to 1,2,4,6-tetraphenylpyridinium perchlorate on reaction with N,N-diphenylurea. The reaction of pyrylium perchlorates with thiosemicarbazide and semicarbazide leads to 1-thiocarbamido- and 1-carbamidopyridinium salts. The latter reacts with 2,4,6-triphenylpyrylium perchlorate to give 1-aminopyridinium salts, which were acylated with acetic anhydride. Difficult-to-obtain 2-alkylthio-4,6-diarylpyrimidines were synthesized in 40–93% yields by the reaction of 2,4,6-triarylpyrylium salts with S-alkylisothioureas.Translated from Khuniya Geterotsiklicheskikh Soedinenii, No. 3, pp. 324–328, March, 1979.     

Synthesis of some vinyl-substituted pyrylium salts and their intermediates

The preparation of vinyl-substituted pyrylium salts and their intermediates is described. These monomers and intermediates have been derived from syntheses based on p-2-hydroxyethoxybenzaldehyde and 4-methoxypyrylium salts. Treatment of the hydroxybenzaldehyde with acetophenone gives a hydroxypyrylium intermediate which, when methacrylated, gives a pyrylium methacrylate. Methacrylation of the hydroxy-benzyldehyde followed by condensation with methylpyrylium salts gives styryl-pyrylium methacrylates. Displacement of the methoxy group in methoxypyrylium salts with ethanolamine derivatives followed by methacrylation yields a series of aminopyrylium methacrylates. The preparation of a divinylpyrylium urethane and a pyrylium-type copolymer is also described.     

Synthesis of pyrylium salts and pyridine bases by the bisacylation of cyclic tertiary alcohols

The catalytic acylation of 1-methyl- and 1-ethylcyclopentan-1-ols, 1-methyl- and 1-ethylcyclohexan-1-ols, 1-methylcycloheptan-1-ol, and 1-methyl- and 1-ethyl-1-tetralols with carboxylic acid anhydrides in the presence of 70% HClO₄ has been studied. A method for the synthesis of substituted 3,4-cycloalkeno-3,4-dihydro(3,42, 1)naphthopyrylium salts and the corresponding pyridine bases has been developed.     

Donor-functionalized polydentate pyrylium salts and phosphinines: synthesis, structural characterization, and photophysical properties

A series of donor-functionalized pyrylium salts have been prepared by classical condensation reactions which were further converted into the corresponding thienyl- and pyridyl-substituted polydentate lambda(3)-phosphinines by reaction with P(SiMe(3))(3). Further chemical modification of these phosphorus heterocycles with Hg(OAc)(2) in the presence of methanol resulted in the formation of lambda(5)-phosphinines. The photophysical properties of a selected series of thienyl- and pyridyl-functionalized pyrylium salts, lambda(3)- and lambda(5)-phosphinines, were investigated and the results compared and supported by theoretical calculations on the DFT level. Significant fluorescence was observed for the pyrylium salts and lambda(5)-phosphinines. In contrast, the heteroaromatic substituted lambda(3)-phosphinines show very little emission which is consistent with the low oscillator strength predicted by DFT calculations for this pi-->pi* transition. Furthermore, all three classes of compounds show readily observable phosphorescence in solution, which was determined by time-gated detection at low temperature.     

溴化苄基取代吡啶类季铵盐的制备和抗菌性能

抗菌材料和抗菌制品的研究与应用一直是世界各国研究的重要课题~([1-3]),其中有机抗菌剂占据主要地位.季铵盐是研究比较多的一类有机抗菌剂,它们表现出良好的物理性质,如胶束浓度低,黏弹性好和溶解性强~([4]),同时此类抗菌剂具有强效的抗菌作用~([5]),引起了人们的极大兴趣.季铵盐广泛应用于医药、卫生、食品、饲料工业、农业、纺织、塑料、橡胶、造纸、水处理、油田开采、涂料、日常生活等多种领域~([6-10]).     

Synthesis of novel spiro imidazolium salts as chiral ionic liquids

A library of 13 novel chiral spiro imidazolium salts has been synthesized. The effects of N-substituents and counteranions on the melting point of spiro bis(imidazolium) salts are studied in efforts toward the development of room temperature chiral ionic liquids.     

Synthesis of 2-aryl-3,4,5,6-bis(trimethylene) pyrylium salts and the corresponding pyridine bases

2-Aryl-3,4,5,6-bis(trimethylene)pyrylium perchlorates were obtained by acylation of cyclopentylidenecyclopentanone with aromatic acid chlorides in the presence of anhydrous aluminum chloride with subsequent treatment with 70% perchloric acid. The synthesized salts were converted to the corresponding pyridine bases.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1461–1463, November, 1972.     

Synthesis of some phenothiazinyl and carbazolyl pyrylium salts

2,6-Diphenyl-4H-pyran-4-one in the presence of phosphorus oxychloride reacted with phenothiazine to give a pyryliurn salt which was bonded in the 4-position to the nitrogen atom of phenothiazine. Carbazole gave a similar type of product. When the N-methyl derivatives of phenothiazine and carbazole were allowed to react under the same conditions, the coupling took place on the phenyl ring para to the nitrogen atom. In contrast to phenothiazine, benzo[a]-phenothiazine gave a product arising by coupling into the phenyl ring.     

Synthesis of condensed derivatives of indolo[2,3-c]pyrylium salts and β-carbolines

Tetra- and pentacyclic indole [2,3-c] pyrylium salts were obtained by acylation of 2-(3-indolyl) dimedone and 2- (1-ethyl-3-indolyl)indan-1,3-dione. The latter salts by the action of ammonia are converted to the corresponding -carbolines — derivatives of the natural alkaloid harman.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 363–366, March, 1985.     

Synthesis and antimicrobial studies of new pyridine derivatives

2-(p-Acetylaminobenzenesulfonylamido)-substituted benzothiazoles were prepared from 2-amino-substituted benzothiazoles and p-acetamidobenzenesulfonyl chloride using a mixture of pyridine and Ac₂O, which formed an electrophilic N-acetyl- pyridinium complex facilitating condensation to give the desired products by removal of HCl. 2-[4-(Substituted benzothiazol-2-yl)aminosulfonylanilino]pyridine-3-carboxylic acids (synthesized from 2-chloropyridine-3-carboxylic acid and the corresponding substituted 2-(p-aminobenzenesulfonylamido)benzothiazole in 2-ethoxyethanol using Cu-powder and K₂CO₃) were then converted to acid chlorides, which on further reaction with piperazine and 4-methoxyphenylpiperazine yielded the corresponding 2-[4-(substituted benzothiazol-2-yl)amino-sulfonyl]anilino-3-(piperazinocarbonyl) pyridine and 2-[4-(substituted benzothiazol-2-yl)amino-sulfonyl]anilino-3-[(4-methoxyphenyl)piperazin-1-yl-carbonyl]pyridine. The structures of the new compounds have been established on the basis of their elemental analyses as well as IR, ¹H NMR, and mass-spectral data. All the compounds have been screened for antimicrobial activity and found to possess considerable antibacterial activity.     

Synthesis of a new series of pyridine and fused pyridine derivatives

The reaction of 4-methyl-2-phenyl-1,2-dihydro-6-oxo-5-pyridine- carbonitrile (1) with arylidene malononitrile afforded isoquinoline derivatives 2a,b. 6-Chloro-4-methyl-2-phenyl-5-pyridinecarbonitile (3) obtained by chlorination of compound 1 with phosphoryl chloride was converted into 6-amino-4-methyl-2-phenyl-5-pyridinecarbonitrile (4) and 6-hydrazido-4-methyl-2-phenyl-5-pyridinecarbonitrile (5) in good yield, through reactions with ammonium acetate and hydrazine hydrate, respectively. Treatment of 4 with ethyl acetoacetate, acetic anhydride, formic acid, urea and thiourea gave the corresponding pyrido [2,3-d] pyrimidine derivatives 7-10a,b. A new series of 6-substituted-4-methyl-2-phenyl-5-pyridine carbonitriles 11-13 has been synthesized via reaction of 4 with phenyl isothiocyanate, benzenesulphonyl chloride and acetic anhydride. Treatment of 4 with malononitrile gave 1,8-naphthyridine derivative 14. The reactivity of hydrazide 5 towards acetic acid, phenylisothiocyanate and methylacrylate to give pyrazolo-[3,4-b]-pyridine derivatives 15-17 was studied. Treatment of 5 with acetic anhydride, phthalic anhydride and carbon disulphide gave pyridine derivatives 18,19 and 1,2,4-triazolo-[3,4-a]-pyridine derivative 20.