Search results for "Ketone"
showing 10 items of 337 documents
1967
Enamines derived from cyclic ketones behave as difunctional intermediates when treated with phenyl isocyanate to produce dicarboxanilides. Reaction of bis(4-isocyanatophenyl)-methane with 1-N-morpholino-1-cyclopentene in DMSO leads to poly[iminocarbonyl(2-morpholino-1-cyclopenten-1.3-ylene)carbonylimino-p-phenylenemethylene-p-phenylene], a polyamide. The effects of various cyclic enamines and diisocyanates on the polymerization are surveyed. Morpholine and piperidine are more effective than pyrrolidine or dimethylamine when incorporated into cyclopentanone enamines. The molecular weight of the polymer decreases when the ring size of the ketone component is increased. The efficiency of the d…
Synthesis of trifluoromethylated 2-benzoyl- and 3-aminoimidazoles from ring rearrangement of 1,2,4-oxadiazole derivative
2008
Fluoroalkylated 2-ylamino-imidazoles have been synthesized by reaction of 3-amino-5-phenyl-1,2,4-oxadiazole with fluorinated b-dicarbonyl compounds and subsequent base-induced BoultoneKatritzky Rearrangement (BKR) of the isolated b-enaminocarbonyl intermediate. Alternatively, one-pot reactions performed in the presence of Montmorillonite K10 favoured the condensation at the 3-amino moiety of the oxadiazole and, in some cases, allowed the direct synthesis of 2-benzoylamino-imidazoles. Hydrolysis of 2-benzoylamino-imidazoles easily yielded fluorinated 2-amino-imidazoles targets.
Crystal structure and Hirshfeld surface analysis of a pyridiniminium bromide salt: 1-[2-(adamantan-1-yl)-2-oxoethyl]pyridin-4-iminium bromide
2018
The asymmetric unit of the title pyridiniminium halide salt comprise of one cation and one anion. In the crystal, molecules are linked by N—H⋯Br and C—H⋯O hydrogen bonds, C—H⋯π interactions, and π–π interactions into layers. The intermolecular interactions in the crystal structure are quantified by Hirshfeld surface analysis.
Fibril formation and toxicity of the non-amyloidogenic rat amylin peptide.
2012
Full-length native rat amylin 1-37 has previously been widely shown to be unable to form fibrils and to lack the toxicity of the human amylin form leading to its use as a non-amyloidogenic control peptide. A recent study has suggested that rat amylin 1-37 forms amyloidogenic β-sheet structures in the presence of the human amylin form and suggested that this property could promote toxicity. Using TEM analysis we show here fibril formation by synthetic rat amylin 1-37 and 8-37 peptides when the lyophilized HPLC purified peptides are initially dissolved in 20 mM Tris-HCl. Dissolution of synthetic rat amylin 1-37 and 8-37 peptides in H(2)O or phosphate buffered saline failed to produce fibrils.…
Unexplored nucleophilic ring opening of aziridines.
2010
The reactivity of dianions of carboxylic acids towards aziridines has been studied. Although, a similar reactivity to that of enolates from ketones, esters or amides has been observed, the method directly yields g-aminoacids in one step. The method is complementary of previous results of enenediolate reactivity with other electrophiles. A comparative study with the reactivity of this enediolates with epoxides is included.
One-pot synthesis of fluorinated 2-amino-pyrimidine-N-oxides. Competing pathways in the four-atom side-chain rearrangements of 1,2,4-oxadiazoles
2006
Abstract Trifluoromethylated 2-amino-pyrimidine N-oxides have been synthesized by reaction of the 3-amino-5-methyl-1,2,4-oxadiazole with trifluoromethyl-β-diketones in the presence of perchloric acid, followed by hydrolysis. In this ring-to-ring transformation an initial formation of (unisolated) 1,2,4-oxadiazole-pyrimidinium salts, and subsequent ring-opening at the oxadiazole moiety occurs. Isolation of 2-(hydroxyamino)-pyrimidine from the reaction mixture evidenced the presence of a competing pathway where the N(4) nitrogen of the oxadiazole is involved in the formation of a regioisomeric pyrimidinium salt. The effect of the trifluoromethyl group on the product distribution is discussed.…
Sorption kinetic of aroma compounds by edible bio-based films from marine-by product macromolecules: Effect of relative humidity conditions
2019
International audience; Edible films based on gelatin and chitosan have high gas and aroma barrier properties. This study focused on their capability to sorbed/retain aroma compounds (1-hexanal, 2-hexen-1-ol, 1-hexanol, 3-hexanone and phenol) at three relative humidity level (≤2%, 53% or 84% RH). Whatever the relative humidity condition, the order of sorption is keton (3-hexanone) < aldehyde (1-hexanal) < aliphatic alcohols (2-hexen-1-ol and 1-hexanol) < phenol. This order could be related to the intrinsic chemical properties of aroma compounds. The increase in moisture enhanced the sorption at the highest RH for all the aroma compounds. However, a competition between water and aliphatic al…
Total Synthesis of Lavendamycin by a [2+2+2] Cycloaddition
2011
The total synthesis of the bacterial-derived, pentacyclic, antitumor antibiotic lavendamycin has been achieved through a highly convergent strategy. The key step of this synthesis is a ruthenium-catalyzed [2+2+2] cycloaddition of an electron-deficient nitrile to an alkynyl-ynamide to prepare the carboline scaffold. The elaborate cycloaddition substrate is obtained in few steps by an N-ethynylation using alkynyliodonium salt chemistry and two palladium-catalyzed cross-coupling reactions. An efficient synthesis of a halogenated quinoline-5,8-dione building block starting from hydroquinone is presented.
An unexpected ring carboxylation in the electrocarboxylation of aromatic ketones
2006
The electrocarboxylation of various aromatic ketones, carried out in N-methyl-2-pyrrolidone (NMP) in a diaphragmless cell equipped with a carbon cathode and an aluminium sacrificial anode, yielded, among the products, the target hydroxy acids, the corresponding alcohols and pinacols and, quite surprisingly, detectable amounts of substituted benzoic acids and cycloexene carboxylic acids. These compounds arise from a never reported before electrocarboxylation on the aromatic ring, respectively, for substitution of an aromatic hydrogen and from an addition reaction. For example, the electrocarboxylation of acetophenone gave rise to the substituted benzoic acids in ortho, para and meta position…
Reaction of 2-acetyltetralone with some esters of benzoic acid
1986
In order to investigate the pharmacological screening of a number of pyran-4-ones their synthesis by cyclization with sulphuric acid of the corresponding 1,3,5-triketones has been carried out with high yields. In the course of preparation of the latter the reaction of 2-acetyltetralone with some esters of benzoic acid derivatives has been studied and in particular, for a number of them, an interesting nucleophilic substitution of a chlorine atom with an alkoxy group on a benzenic nucleus has been evidenced.