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181.
Unexpected One‐pot Synthesis of Novel 2‐Aminopyrimidine‐4‐ones under Microwave Irradiation
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One‐pot, three‐component condensation of guanidine, ethylbenzoylacetate and various aromatic aldehydes in the presence of NaHCO3 have been investigated by microwave irradiation. The aromatic aldehydes bearing electron‐withdrawing groups undergo condensation with guanidine and ethylbenzoyl‐acetate to afford ethyl‐2‐amino‐4‐aryl‐1,4‐dihydro‐6‐phenylpyrimidine‐5‐carboxylate derivatives via Biginelli reaction. However, reaction of the aromatic aldehydes having electron‐releasing groups with guanidine and ethylbenzoylacetate did not give the corresponding dihydropyrimidines. Instead, novel 2‐amino‐5‐benzoyl‐5,6‐dihydro‐6‐arylpyrimidine‐4(3H)‐ones were obtained via an unexpected mechanism. 相似文献
182.
Mohammad Ali Rasouli Mohammad Mahdavi Mina Saeedi Parviz Rashidi Ranjbar Abbas Shafiee Alireza Foroumadi 《Journal of heterocyclic chemistry》2015,52(2):386-391
The present study provides an efficient strategy for the preparation of novel N‐substituted‐4‐methyl‐quinolin‐1(2H)‐one derivatives via two‐step Ugi/Heck reaction. The procedure is based on the Ugi coupling between 2‐bromoanilines, various aromatic aldehydes, vinylacetic acid, and isocyanides, and then intramolecular Heck reaction, which leads to the formation of the title compounds in good yields. 相似文献
183.
Zahra Ghiyasabadi Saeed Bahadorikhalili Mina Saeedi Mona Karimi-Niyazagheh Seyedeh Sara Mirfazli 《Journal of heterocyclic chemistry》2020,57(2):606-610
In this work, an efficient, user-friendly, and simple procedure was reported for the preparation of indole derivatives catalyzed by the heterogeneous SBA-15-Pr-SO3H via Fischer indole pathway. The title compounds were synthesized from various arylhydrazines and ketones in the presence of 3 mol% of the catalyst in the refluxing ethanol. 相似文献
184.
Shiyu Wang Mina Huo Ce Zhang Jianping Liu Yimin Song Shuqian Cao Yuhu Yang 《European Journal of Mechanics - A/Solids》2011,30(6):820-827
The distinctive wave vibration of a ring gear affected by mesh effect is investigated based on the inherent symmetry of spur planetary gears. Compared to prior analysis, this work mainly examines the forced flexural and extensional vibrations. The superposition principle and the Fourier series are introduced to jointly deal with the wave vibrations. The dynamics of the ring gear shows that the effect of the mesh phase on the wave vibration is mainly embodied by the specific relationships between the tooth number, the planet number, the largest common factor of them, the planets’ circumferential position, and the excited wave numbers in the typical rotational, translational and planet modes. For the equal systems, the three modes can be possibly excited depending on the specific mesh phase. And the dominant vibration orders of them are 0, 1 and 2, respectively. The non-zero lowest order is equal to the largest common factor of the two numbers. But for the diametrical ones, only the first two modes can be excited, and the dominant orders of them are 0 and 1, respectively. And the lowest non-zero wave number is 2 for even tooth number and 1 for odd tooth number. As a typical application, these relationships can be used to predict and suppress some potential wave resonances of the ring gear by optimizing the ring-planet mesh phase. The main results are demonstrated with finite element examples and comparisons with the existing literature. 相似文献
185.
利用粘度碰撞积分方程的直接反演方法计算了两个二元气体混合体系即苯-甲醇和甲烷-四氟甲烷的低密度势能.另外利用动力学理论以及对应态原理计算了两种体系不同温度和不同比例的粘度系数和扩散系数.计算结果和实验数据具有较好的一致性. 相似文献
186.
Masoumeh Zakeri Majid M. Heravi Mina Saeedi Narges Karimi Hossein A. Oskooie Niloofar Tavakoli‐Hoseini 《中国化学》2011,29(7):1441-1445
An efficient one‐pot condensation of β‐naphthol, aldehydes and cyclic 1,3‐dicarbonyl compound has been achieved with ionic liquids as catalyst, thus a variety of 8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐one derivatives were prepared in good yields. The present approach offers several advantages such as shorter reaction times, good yields and mild reaction conditions. 相似文献
187.
A novel ionic liquid (IL) bonded fused-sil-ica fiber for headspace solid-phase microextraction (HS-SPME)/gas chromatography-flame ionization detection (GC-FID) of methyl tert-butyl ether (MTBE) in a gasoline sample was prepared and used. The new proposed chemically bonded fiber has better thermal stability and durability than its corresponding physically coated fiber. Another advantage is that no spacer was used for the purpose of bonding the IL to the surface of the fused-silica. The latter advantage makes the preparation of these fibers easier with lower cost than those prepared using sol–gel method. The ionic liquid 1-methyl-3-(3-trimethoxysilyl propyl) imidazolium bis(trifluoromethylsulfonyl) imide was synthesized and cross linked to the surface of the fused-silica fiber. Then, the chemically IL-modified fibers were applied to the headspace extraction of MTBE. The chemically IL-modified fibers showed improved thermal stability at temperatures up to 220 °C relative to the physically IL-modified fibers (180 °C). The chemically bonded IL film on the surface of the fused-silica fiber was durable over 16 headspace extractions without any significant loss of the IL film. The calibration graph was linear in a concentration range of 2–240 μg L−1 (R2 = 0.996) with the detection limit of 0.1 μg L−1 level. The reproducibility (RSD %, n = 6) of the new IL bonded fused-silica fiber (8.9%) was better than the physically coated fiber (12%) suggesting that the proposed chemically IL-modified fiber is more robust than the physically IL-modified fiber. The optimum extraction conditions were the followings: 40 °C extraction temperature, 12 min extraction time, 30 s desorption time and sample agitation at 200 rpm. 相似文献
188.
Milne JE Storz T Colyer JT Thiel OR Dilmeghani Seran M Larsen RD Murry JA 《The Journal of organic chemistry》2011,76(22):9519-9524
A new convenient and scalable synthesis of phenylacetic acids has been developed via the iodide catalyzed reduction of mandelic acids. The procedure relies on in situ generation of hydroiodic acid from catalytic sodium iodide, employing phosphorus acid as the stoichiometric reductant. 相似文献
189.
A new ionic liquid (IL) based solid-phase microextraction (SPME) fiber was investigated and used for headspace (HS) extraction of methyl tert-butyl ether (MTBE) in a gasoline sample. Using the new IL coated HS-SPME fiber with the combination of gas chromatography-flame ionization detection (GC-FID); sub-to-low μg L−1 concentrations of MTBE were detected. Four different ILs including 1-butyl-3-methylimidazolium tetraflouroborate ([C4C1IM] [BF4]), 1-octyl-3-methylimidazolium tetraflouroborate ([C8C1IM] [BF4]), 1-octyl-3-methylimidazolium hexaflourophosphate ([C8C1IM] [PF6]) and 1-ethyl-3-methylimidazolium ethylsulphate ([C2C1IM] [ETSO4]) were synthesized and examined for extraction, preconcentration and determination of MTBE. It was observed that [C8C1IM] [BF4] showed the highest extraction efficiency and possessed the best extractability for MTBE. The fiber coating takes up the compounds from the sample by absorption in the case of liquid coatings. The calibration graph was linear in a concentration range of 1-120 μg L−1 (R2 > 0.994) with the detection limit of 0.09 μg L−1 level. The new IL-coated fiber was applied successfully for the determination of MTBE in a gasoline sample with good recoveries between 90 and 95%. 相似文献
190.
Mina Jamre Nafise Salek Amir R. Jalilian Leila Moghaddam Mojtaba Shamsaee Mohammad Mazidi Mohammad Ghannadi-Maragheh 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(3):543-549
Bleomycin (BLM) has been labeled with various radioisotopes and widely used in therapy and diagnosis. 191Os is a parent radionuclide with 15.4 day half-life and decays by beta emission to 191mIr, which is a radionuclide with 4.96 s half-life. BLM was labeled with 191Os-hexachloro-osmate and its distribution and stability in wild-type mice was determined. The complex was obtained at the
pH 2 in normal saline at 90 °C in 48 h. Radio-TLC showed an overall radiochemical yield of 93–97%, radio-chemical purity > 97%.
The biodistribution study for 191Os-hexachloro-osmate and 191Os-BLM were carried in wild type-mice up to 14 days. Lungs, liver and spleen uptake increased 24–72 h after administration
of 191Os-BLM. 24 h after administration, the radioactivity of the kidney increased and remained constant. 相似文献