排序方式: 共有87条查询结果,搜索用时 15 毫秒
11.
Kashinath D Tisserand S Puli N Falck JR Baati R 《European journal of organic chemistry》2010,2010(10):1869-1874
Nucleophilic mixed chromium(II) and chromium(III) acetylides are generated from the smooth reduction of primary 1,1,1-trichloroalkanes with chromium(II) chloride in the presence of an excess amount of triethylamine at room temperature. These species arise from chromium(III) vinylidene carbenoids. It has been demonstrated that uncommon low-valent Cr(II) acetylides are formed by C-H insertion of Cr(II)Cl(2) into terminal alkynes, formed in situ through the Fritsch- Buttenberg-Wiechell (FBW) rearrangement, whereas Cr(III) acetylides are concomitantly generated by HCl elimination from the chromium(III) vinylidene carbenoid. Both divergent pathways result, overall, in the formation of nucleophilic acetylides. In situ trapping with electrophilic aldehydes afforded propargyl alcohols. Furthermore, deuteration experiments and the use of deuterium labeled 1,1,1-trichloroalkane substrates demonstrated the prevalence of low-valent Cr(II) acetylides, potentially useful, yet highly elusive synthetic intermediates. 相似文献
12.
Grigor’eva N. G. Agliullin M. R. Kostyleva S. A. Bubennov S. V. Bikbaeva V. R. Gataulin A. R. Filippova N. A. Kutepov B. I. Narender Nama 《Kinetics and Catalysis》2019,60(6):733-743
Kinetics and Catalysis - The catalytic properties of samples of amorphous mesoporous aluminosilicate ASM with different Si/Al molar ratios (40, 80, 160) were studied in the synthesis of practically... 相似文献
13.
N. G. Grigor’eva N. A. Filippova A. R. Gataulin S. V. Bubennov M. R. Agliullin B. I. Kutepov Nama Narender 《Russian Chemical Bulletin》2017,66(11):2115-2121
Physicochemical characteristics of microporous zeolites of various structural type (FAU, BEA, MTW), micro-meso-macroporous zeolite (H-Ymmm), and mesoporous aluminosilicate (ASM) were studied. Their catalytic activity in the reaction of aniline with acetone was examined. It was found that 2,2,4-trimethyl-1,2-dihydroquinoline was the main reaction product on the catalysts H-Ymmm and ASM (selectivity up to 68% at 100% conversion of aniline), while the reaction on zeolites with microporous structure mainly gave N-phenyl-2-propanimine (selectivity up to 91%). 相似文献
14.
K. Praveen Kumar S. Satyanarayana P. Lakshmi Reddy G. Narasimhulu Narender Ravirala B.V. Subba Reddy 《Tetrahedron letters》2012,53(14):1738-1741
Iodine is found to be a highly efficient catalyst for the three-component coupling (3CC) of aldehydes, β-naphthol, and 1,3-dimethylbarbituric acid under solvent-free conditions to afford the corresponding 8,10-dimethyl-12-aryl-12H-naphtho[1′,2′5,6]pyrano[2,3-d]pyrimidine-9,11-diones in good yields with high selectivity. The use of readily available iodine makes this method very simple, convenient, and cost-effective. 相似文献
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16.
P. Lakshmi Reddy D. Ashok Kumar M. Lakshmi Devi T. Veera Reddy B.V. Subba Reddy R. Narender 《Tetrahedron letters》2014
A three-component, four center Ugi reaction of 3-(1-(2-aminophenyl)-5-phenyl-1H-pyrrol-2-yl)propanoic acid with aromatic aldehyde and t-butyl isocyanide has been achieved to produce a novel class of N-tert-butyl-2-(6-oxo-11-phenyl-7,8-dihydrobenzo[b]pyrrolo[1,2-d][1,4]diazacine-5(6H)-yl)-2-phenylacetamides in moderate to good yields. 相似文献
17.
Mahender Reddy Marri Swamy PerakaArun Kumar Macharla Naresh MamedaSrujana Kodumuri Narender Nama 《Tetrahedron letters》2014
A new and efficient protocol is described for the one-pot synthesis of benzimidazoles from a variety of aryl alcohols and 1,2-diaminoarenes. The yields were ranging from moderate to excellent. Moreover, the present method is utilizing alcohols instead of aldehydes and the reactions are carried out under solvent- and catalyst-free conditions, offering an environmentally benign process. 相似文献
18.
A new chemical access has been developed for the synthesis of 3′-acetyl-4′-hydroxychalcones from 1-(5-acetyl-2-hydroxy-phenyl)-ethanone and various substituted benzaldehydes via a regioselective Claisen-Schmidt condensation using borontrifluoride-etherate (BF3·OEt2) at room temperature, in good to excellent yields within 12-24 h. Application of this methodology has also been demonstrated in the synthesis of chalcone hybrids. 相似文献
19.
Anand Kumar Sharma Narender Kumar Kaushik 《Monatshefte für Chemie / Chemical Monthly》1983,114(4):399-405
A series of [Cp 2ZrL]+[ROCS2]? complexes whereL is the conjugate base of acetylacetone, benzoylacetone or 8-hydroxyquinoline andR=Me,Et ori-Pr have been synthesised in aqueous medium by the reaction of [Cp 2ZrL]+Cl? withROCS 2 ? K+. Various physico-chemical studies carried out for these complexes indicate that all the complexes are 1:1 electrolytes in which the ligandL is bidentate, consequently there is a tetrahedral coordination about the zirconium atom. 相似文献
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J.S. Yadav B.V. Subba Reddy K.V. Raghavendra Rao R. Narender 《Tetrahedron letters》2009,50(27):3963-5403
The cyclic 1,3-dicarbonyl compounds undergo smooth cyclization with aryl propargyl alcohols in the presence of 10 mol % indium tribromide in refluxing dichloroethane to produce 2,4-diarylpyran derivatives in good yields with high selectivity. 相似文献