Papers by Keyword: Synthesis

Abstract: Aurones belong to a class of heterocyclic flavonoids which contains a benzofuran element associated with a benzylidene linked in position 2. Aurones possess a wide range of pharmacological activities and biological activities, such as antitumor, antifungal, phytoalexin and so on. A novel series of 2-ayl-yl (5-methacrylate) aurone analogues were synthesized in six steps with the overall yield of 11%-13% and characterized by ¹H NMR. Among the key intermediates and target compounds, 2-(2-furan-ylmethylene)-5-methacrylate-benzofuran-3(2H)-one (7a) and 2-(2-thienyl-ylmethylene)-5-methacrylate-benzofuran-3(2H)-one (7b) have never been reported before. Primary biological activities evaluation showed that 7a exhibited good inhibitory activities against K562 with an IC₅₀ of 2.18 μM and against HepG2 with an IC₅₀ of 3.95μM.

Abstract: Directly starting from D,L-lactic acid (LA) and melamine (MA), novel star-shaped biodegradable material poly (lactic acid-co-melamine) [P(LA-co-MA)] as a kind of potential flame retardant is synthesized via melt polycondensation. When the molar feed ratio n(LA)/n(MA) is 60/1, the optimal synthetic conditions are discussed. After the prepolymerization at 140 °C for 8 h, using 0.4 wt % stannous chloride as the catalyst, the melt copolymerization at 160 °C for 8 h gives the copolymer with the biggest intrinsic viscosity 0.87 dLg^-1.

Abstract: 1-(3,3-dimethylcyclohexyl) ethyl acetate was synthesized by the reaction of dihydromycene with acetic acid in the presence of sulfuric acid. The effecting factors including the amount of catalyst, the reaction temperature, the molar ratio of raw materials and the reaction time were investigated. The experimental results showed that the molar raio of the dihydromyrcene to acetic acid to sulfuric acid was 1:3:0.2, the reaction temperature is 60 °C and the reaction time was 6.5 h. The yield reached 45.3%. The structure of product was characterized by gas chromatography, mass spectrometry, infrared spectroscopy and nuclear magnetic resonance. The odor evaluation result indicated that the product had a sweet, woody, floral odor.

Abstract: A series of new roflumilast analogues with Crown ether structures were designed and synthesized. Crown-ether-type benzaldehydes were first prepared from 3,4-dihydroxybenzaldehyde with 1-bromo-3-chloropropane and 1-chloro-2-(2-chloroethoxy) ethane respectively, then after oxidation, acylation and amidation as the last step with 3,5-dichloropyridin-4-amine the roflumilast analogues were obtained. These compounds were characterised by ¹H NMR, IR, ESI-MS and elemental analysis.

Abstract: This work presents the synthesis and hydrodesulfurization performance of NiMo sulfide catalysts supported on γ-Al₂O₃ during the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The catalysts were synthesized by the co-impregnation method using an atomic ratio of Ni=Ni/(Ni+Mo)=0.5. The materials were characterized by N₂ physisorption, XRD and HRTEM. This catalyst exhibited the larger pore size and high specific surface area, as well as better morphological properties. The catalytic activity was evaluated using a high-pressure batch reactor at 280 °C and 3.0 MPa. The catalytic activity during HDS-DBT indicated that the NiMoS/γ-Al₂O₃ catalyst was better than that NiMoS/γ-Al₂O₃ catalyst. the NiMoS/γ-Al₂O₃ catalyst exhibits higher DDS selectivity (3.0) than NiMo/γ-Al₂O₃ catalyst (2.55).

Abstract: (S)-methyl 3-(((benzyloxy) carbonyl) amino)-7-hydroxyheptanoate (7), a fragment of a novel cytotoxic cyclodepsipeptide onchidin^[, which shows moderate cytotoxic activity, was synthesized through six steps. The key stereoselective synthesis of beta-amino acid derivatives (7) was achieved by the Arndt-Eistert homologation reaction^[2,3] and Wolff rearrangement reaction^[4].

Abstract: A practical synthetic route towards 1,2,3-tri-O-acetyl-5-deoxy-D-ribofuranose from D-ribose is described, which started from D-ribose and proceeded through ketalization,esterification,reduction,hydrolysis and acetylation in more than 30% overall yield.

Abstract: (R)-2,2-Dimethyl-3-(tert-butoxycarbonyl)-4-ethynylox-azolidine, an intermediate of the natural product jaspine B, which was isolated from various sponges and endowed with cytotoxic activity against several human carcinoma cell lines, was synthesized from L-Serine in overall yield 43% through seven steps, including esterification, Boc protection, acetonization, reduction, Swern oxidation and Corey-Fuchs reaction.

Abstract: Polyethylene glycol-400 was used as phase transfer catalyst in reaction of dichloropyridine and sodium thiomethoxide to form 2-methylthiopyridine with a yield of 97.8%. Then 2-methylthiopyridine and sodium hypochlorite were added respectively to oxidize and bromize it to synthesis 2-Pyridyl tribromomethyl sulfone, with the purity of 99.6% and yield of 93.3%. Mass ratio of dichloropyridine versus polyethylene glycol-400 is 1:0.18, and molar ratio of dichloropyridine versus sodium thiomethoxide is 1:1.2. The optimum conditions to prepare sodium hypochlorite are a temperature at-5 to 0 °C, a molar ratio of bromine versus sodium hydroxide being 1:4. Proved optimum conditions to synthesis 2-pyridyl tribromomethyl sulfone are a temperature at (80±1)°C, reaction time for 5 hours and the molar ratio of 2-methylthiopyridine versus bromine being 1:6.58. Probable mechanism of synthetizing 2-methylthiopyridine was speculated, properties with structure of resultant substances were characterized by melting point apparatus, IR spectra and magnetic resonance spectrum.

Abstract: The title compounds thienopyrimidine-based S-glycoside analogues were synthesized through the nucleophilic addition/cyclization/glycosylation reactions in good yields from easily accessible starting materials under mild reaction conditions. All of compounds were characterized by NMR, MS, IR and elemental analysis. The efficient approach allowed the facial synthesis of small libraries of thienopyrimidine-based S-glycoside analogues with different structural motifs for biological screening.