Search results for "Class"
showing 10 items of 38174 documents
Synthesis of Amino-1,2,4-triazoles by Reductive ANRORC Rearrangements of 1,2,4-Oxadiazoles
2010
The reaction of various 1,2,4-oxadiazoles with an excess of hydrazine in DMF has been investigated. 3-Amino- 1,2,4-triazoles are produced through a reductive ANRORC pathway consisting of the addition of hydrazine to the 1,2,4-oxadiazole followed by ring-opening, ring-closure, and final reduction of the 3-hydroxylamino-1,2,4-triazole intermediate. The general applicability of 1,2,4-oxadiazoles ANRORC reactivity is demonstrated also in the absence of C(5)-linked electron-withdrawing groups.
1,1prime-Binaphthyl-2-methylpyridinium-based peroxophosphotungstate salts: synthesis, characterization, and their use as oxidation catalysts
2009
A series of 1,1′-binaphthyl-2-methylammonium and pyridinium salts 6, 7, and 8 was synthesized through the coupling reaction of 2-(bromomethyl)-1,1′-binaphthalene (5) with the dendritic tetraallyl pyridinedicarbinol dendron 2 as well as triethylamine and 4-tert-butylpyridine. Tetraallyl pyridinedicarbinol dendron 2 was prepared by allylation of commercially available diethyl pyridine-3,5-dicarboxylate (1). The allylation of 2 with allyltrimethylsilane in the presence of boron trifluoride was unsuccessful, as tetraallyl pyridinedicarbinol trifluoroboron adduct 3 was obtained instead of expected hexaallylpyridine compound 4. The catalytic hydrogenation of allyl groups of the ammonium salt of 2…
Oxidation of aromatic alcohols in irradiated aqueous suspensions of commercial and home-prepared rutile TiO(2): a selectivity study.
2008
WOS: 000256241700021
Influence of harvesting time on composition of the essential oil of Thymus capitatus (L.) Hoffmanns. & Link. growing wild in northern Sicily and its …
2019
One of the main factors affecting historical art crafts material is the biodeterioration performed by bacteria and fungi, in archives, museums or private collections. Several microorganisms cause degradation to the natural organic material such as fibers, woods, and dyes as well as to stone objects. These alterations produce deterioration of physical, chemical, mechanical and esthetic properties. Consequently, in this publication, we report the high antibacterial and antifungal activities of wild thyme essential oil, oil that can be used as an alternative natural tool in the fight against microorganisms affecting historical art crafts.Essential oil of the Thymus capitatus growing wild in no…
Statistical analyses on the essential oil of italian coriander (coriandrum sativum L.) fruits of different ages and origins
2002
Thirty-one samples of Coriandrum sativum L. fruits, of different origin, year of cultivation (harvest) and crop management systems were subjected to volatile component analysis by combining Head Space Solid Phase Microextraction (HS-SPME) with GC/MS. In order to determine the importance of the major sources of volatile variability, some statistical analyses, including Cluster Analysis (CA) and Principal Component Analysis (PCA), were performed on the obtained data. The compounds, which gave the main contribution to the partition and classification of the original data, were α-pinene, p-cymene, γ-terpinene and linalool. The age of the fruits, which ranged from 1–16 years, seemed to generate …
Chemical composition and antimicrobial activity of the essential oil from aerial parts of Micromeria fruticulosa (Bertol.) Grande (Lamiaceae) growing…
2007
The essential oil of aerial parts of Micromeria fruticulosa (Lamiaceae) growing wild in Southern Italy was obtained by hydrodistillation and analysed by GC and GC–MS. Sixty-one compounds, representing 91.3% of the oil, were identified. The major components were γ-terpinene (14.5%), β-caryophyllene (12.6%), p-cymene (8.9%), α-pinene (8.2%) and β-bisabolene (7.2%). The essential oil showed action mainly against Gram-positive bacteria. Copyright © 2007 John Wiley & Sons, Ltd.
[60]Fullerene l -Amino Acids and Peptides: Synthesis under Phase-Transfer Catalysis Using a Phosphine–Borane Linker. Electrochemical Behavior
2017
International audience; A new method to link amino acid and peptide derivatives to [60]fullerene is described. It uses hydrophosphination with a secondary phosphine borane. First, the stereoselective synthesis of secondary phosphine borane amino acid derivatives was achieved by alkylation of phenylphosphine borane with gamma-iodo-alpha-amino ester reagents under phase transfer catalysis (PTC). Second, a sec-phosphine borane amino ester was saponified and coupled with alpha,gamma-diamino esters to afford the corresponding dipeptide derivatives in good yields. Finally, the hydrophosphination reaction of [60]fullerene by the sec-phosphine borane compounds was performed under PTC to obtain C-60…
A Gaschütz–Lubeseder Type Theorem in a Class of Locally Finite Groups
1999
The aim of this paper is to present a Gaschutz–Lubeseder type theorem in the class cL of all radical locally finite groups satisfying min−p for all primes p. Notice that these groups are countable and co-Hopfian by [1, (5.4.8)]. In retrospect, the theory of saturated formations of finite soluble groups began with the results of Gaschutz [3] in 1963. He introduced the concept of “covering subgroup” as a generalization of Sylow and Hall subgroups. These covering subgroups have many of the properties of Sylow and Hall subgroups other than the arithmetic ones. The main idea of Gaschutz’s work was concerned with group theoretical classes having the same properties. He defined a formation F to be…
On the Frattini subgroup of a finite group
2016
We study the class of finite groups $G$ satisfying $\Phi (G/N)= \Phi(G)N/N$ for all normal subgroups $N$ of $G$. As a consequence of our main results we extend and amplify a theorem of Doerk concerning this class from the soluble universe to all finite groups and answer in the affirmative a long-standing question of Christensen whether the class of finite groups which possess complements for each of their normal subgroups is subnormally closed.
UV-B exposure causes DNA damage and changes in protein expression in northern pike (Esox lucius) posthatched embryos.
2012
The ongoing anthropogenically caused ozone depletion and climate change has increased the amount of biologically harmful UV-B radiation, which is detrimental to fish in embryonal stages. The effects of UV-B radiation on the levels and locations of DNA damage manifested as cyclobutane pyrimidine dimers (CPDs), heat shock protein 70 (HSP70) and p53 protein in newly hatched embryos of pike were examined. Pike larvae were exposed in the laboratory to current and enhanced doses of UV-B radiation. UV-B exposure caused the formation of CPDs in a fluence rate-dependent manner, and the CPDs were found deeper in the tissues with increasing fluence rates. UV-B radiation induced HSP70 in epidermis, and…