排序方式: 共有31条查询结果,搜索用时 33 毫秒
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Lilian Buriol Taiana S. München Clarissa P. Frizzo Mara R.B. Marzari Nilo Zanatta Helio G. Bonacorso Marcos A.P. Martins 《Ultrasonics sonochemistry》2013,20(5):1139-1143
Pyrazolo[1,5-a]pyrimidines were synthesized via the ultrasonic sonochemical method using the cyclocondensation reaction of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones [CF3C(O)CH = C(R)(OMe) – where R = Me, Bu, i-Bu, Ph, 4-Me–C6H4, 4-F–C6H4, 4-Cl–C6H4, 4-Br–C6H4, naphth-2-yl and biphen-4-yl] – with 3-amino-5-methyl-1H-pyrazole in the presence of EtOH for 5 min. This methodology has several advantages, for example, it is a simple procedure, it has an easy work-up, mild conditions, short reaction times (5 min) and produces satisfactory yields (61–98%). 相似文献
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Abstract
A new parametrization for the Harmonic Oscillator Model of Aromaticity (HOMA) index to determine aromaticity of heterocycles is introduced. The new HOMA for Heterocycle Electron Delocalization (HOMHED) is based on the experimental data from electron diffraction X-ray for the reference molecules used to estimate the simple, double, and optimal bond lengths. Bond length of “pure” single and double bonds of non-conjugated systems or systems without π-electrons and/or n-electron delocalization were considered. The HOMHED index was determined for a series of five and six heterocycles with C–C, C–N, C–O, C–S, N–N, N–O, and N–S bonds. The π-electron delocalization of these heterocycles was determined by Krygowski-reformulated HOMA and HOMHED and it was proved that HOMHED worked in line with HOMA for all heterocycles, except those containing oxygen, which were found to be weak aromatic from Krygowski rHOMA calculations. 相似文献14.
Efficient microwave-assisted synthesis of 1-aryl-4-dimethylamino methyleno-pyrrolidine-2,3,5-triones
Pâmela S. Vargas Fernanda A. Rosa Lilian Buriol Mariane Rotta Dayse N. Moreira Clarissa P. Frizzo Helio G. Bonacorso Nilo Zanatta Marcos A.P. Martins 《Tetrahedron letters》2012,53(25):3131-3134
A microwave-assisted synthesis of a series of 1-aryl-4-dimethylaminomethylene pyrrolidine-2,3,5-triones from the cyclocondensation reaction of ethyl 5,5,5-trichloro-3-dimethylamino methylene-2,4-dioxopentanoate with aniline, 3- or 4-substituted anilines [where the substituents = 3-Me, 3-OMe, 3-OH, 4-Me, 4-F, 4-Cl, 4-Br, 4-NO2, and 4-COMe] is reported. This process is an efficient alternative to the conventional thermal heating and furnishes the products in a short reaction time (ca. 13 min), under mild conditions and in moderate to good yields (50–76%). 相似文献
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Emerson A. Guarda Mara R.B. Marzari Clarissa P. Frizzo Patrícia M. Guarda Nilo Zanatta Helio G. Bonacorso Marcos A.P. Martins 《Tetrahedron letters》2012,53(2):170-172
Synthesis of 4-alkoxy-1,1-dichloro-3-alken-2-ones [CHCl2C(O)C(R2)C(R1)-OR, where R, R1, R2 = Et, H, H; Me, Me, H; Et, H, Me; Me, –(CH2)2–; Me, –(CH2)3–; Et, Et, H; Et, Bu, H; Et, i-Pr, H; Et, i-Bu, H; Me, Ph, H; Me, thien-2-yl, H] from acylation of enol ethers and acetals with dichloroacetyl chloride, in ionic liquid ([BMIM][BF4] or [BMIM][PF6]) is reported. The synthesis of alkenones [R3–C(O)C(R2)C(R1)-OR], where R/R1/R2/R3 = Et/H/H/Ph, t-Bu/H/H/Ph, Me/-(CH2)4/Ph, Me/-(CH2)4/Me] from the reaction of enol ethers with benzoyl chloride or acetyl chloride, in ionic liquid [BMIM][BF4], is also reported. Last products are described for the first time. 相似文献
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CP 《Journal of Geometry and Physics》1998,28(3-4):384-406
It is known that symmetric orbits in g* for any simple Lie algebra g are equipped with a Poisson pencil generated by the Kirillov-Kostant-Souriau bracket and the reduced Sklyanin bracket associated to the “canonical” R-matrix. We realize quantization of the Poisson pencil CPn type orbits (i.e. orbits in sl(n + 1)* whose real compact form is CPn) by means of q-deformed Verma modules. 相似文献
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Lorenzo D Loayza I Leigue L Frizzo C Dellacass E Moyna P 《Natural product letters》2001,15(3):163-170
Investigation of the volatile fraction from the stem bark of Ocotea opifera Mart. led to the isolation and characterization of asaricin, a phenolic derivative with antifungal and insecticidal activity, as the main component, which is described for the first time for the genus Ocotea. The structure has been established by a study of its mono- and bidimensional NMR spectra and mass spectrometry. 相似文献