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1.
Novel fluorine-containing 1,10-phenanthrolines having a variety of substituents at the 3-position were easily synthesized in moderate yields by the pyridine-ring formation reaction of N-propargyl-5,7-bis(trifluoroacetyl)-8-quinolylamine with various amines, thiols, and phenols. Unexpectedly, the reactive intermediates 1,4-dihydro-1,10-phenanthrolin-4-ols were isolated for the first time in the reactions with dialkylamines. 相似文献
2.
N Rosas P SharmaC Alvarez E GómezY Gutiérrez M MéndezR.A Toscano L.A Maldonado 《Tetrahedron letters》2003,44(43):8019-8022
The condensation of substituted α-keto alkynes with p-nitrobenzaldehyde in the presence of lithium diisopropylamide (LDA) affords highly substituted 5,6-dihydro-4H-oxocin-4-ones in good yields. Surprisingly, no six-membered carbocycles were formed in this 8-endo-dig cyclization to the oxocinone system. 相似文献
3.
An efficient and convenient approach for the construction of various (E)-β-iodovinyl sulfones has been developed through potassium persulfate/tetrabutylammonium iodide-facilitated reaction of sulfonylhydrazides with alkynes. The products were obtained in good to excellent yields. The salient features of this reaction are the applications of a new iodine source, environmentally benign, safer solid oxidant, and shorter reaction time. 相似文献
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A study on the synthesis of (Z)-1,2-bis(2-bromopyridin-3-yl)ethenes, key intermediates in the preparation of 1,10-phenanthrolines, based on selective Sonogashira and Suzuki-Miyaura cross-coupling reactions has been carried out. 相似文献
6.
Krasnov V. P. Levit G. L. Korolyova M. A. Bukrina I. M. Sadretdinova L. Sh. Andreeva I. N. Charushin V. N. Chupakhin O. N. 《Russian Chemical Bulletin》2004,53(6):1253-1256
The influence of the reaction conditions (solvent, base) on the diastereoselectivity of acylation of (±)-3-methyl-2,3-dihydro-4H-1,4-benzoxazine with (S)-naproxen and N-tosyl-(S)-proline chlorides was studied. The highest diastereoselectivity was observed for the reaction carried out in benzene in the presence of aliphatic tertiary amines. 相似文献
7.
A new potential tetradentate ligand, 1,4-bis(N-1-methylimidazol-2-ylmethyl)-1,4-diazacycloheptane (l), together with its CuII complex [CulCl]ClO4 (1), has been reported. The crystal structure of 1, determined by single-crystal X-ray analysis, shows that it is in chiral P212121 space group. The CuII centre is penta-coordinated in square pyramidal geometry and the diazacycloheptane (DACH) ring adopts normal boat configuration. The most striking feature of this complex is the formation of a 3D network bridged through the C-H?Cl hydrogen bonds with the perchlorate anions in the cavities, and stabilized via π-π stacking interactions along the a-direction. The solution behaviour of 1 has been further investigated by UV/Vis and ESR techniques. 相似文献
8.
Shinobu Fujihara Hiromitsu Kozuka Toshinobu Yoko Sumio Sakka 《Journal of Sol-Gel Science and Technology》1994,1(2):133-140
It was shown that a single phase YBa2Cu4O8 (124-phase) could be formed from gels at 1 atm oxygen pressure, and the mechanism of its formation was elucidated. It was found that there are two key routes for the sol-gel formation of the 124-phase, one involving the tetragonal YBa2Cu3O
y
with a low concentration of oxygen defects (tetra-I phase) and the other involving the Ba2Cu3O5.9 as important intermediates of the 124-phase. The rapid formation of these intermediate compounds from the gel was attributed to the small particle size of the oxides and carbonates precipitating at the initial stage of heating. It was thought that the small particles characteristic of sol-gel processing lead to the rapid formation of the intermediate compounds and subsequent precipitation of the 124-phase. 相似文献
9.
Alexander V. Stepakov Michail A. KinzhalovVitaly M. Boitsov Liubov V. StepakovaGalina L. Starova Sergey Yu. VyazminElena V. Grinenko 《Tetrahedron letters》2011,52(24):3146-3149
Reaction of N-aryl substituted maleimides with aliphatic ketazines leads to the formation of 4,5-dihydropyridazin-3(2H)-ones in moderate yields. The reaction proceeds through 1,4-addition of an azine to the maleimide double bond, as confirmed by separation of the corresponding adducts in some cases, which are then converted into 4,5-dihydropyridazin-3(2H)-ones. In addition, the solid-state synthesis of 4,5-dihydropyridazin-3(2H)-ones is demonstrated for the first time. 相似文献
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11.
Dan Niculescu-Duvaz 《Tetrahedron letters》2005,46(40):6919-6922
A novel synthesis is described of the prodrug ZD2767P (in Phase I/II clinical trials) that improves the overall yield from 13% to 45%. The method involves the synthesis of 4-[N,N-bis(2-hydroxyethyl)amino]phenyl chloroformate protected as the bis-silyl ether, coupled with di-tert-butyl glutamate. There are clear advantages of this method compared to the literature procedure. 相似文献
12.
An environmentally benign un-catalyzed one-pot synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols) has been reported via tandem Knoevenagel–Michael reaction of aldehydes with two equivalents of 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one in aqueous medium. 相似文献
13.
Yoko Kameda 《Tetrahedron》2006,62(41):9751-9757
(4R,8R)-4,8-Dimethyldecanal, a common aggregation pheromone of Tribolium flour beetles, has been synthesized from (R)-2,3-O-isopropylideneglyceraldehyde in 11 steps and 7% overall yield. The key step in the synthesis is the highly diastereoselective chelation-controlled radical reaction of ethyl (4S,5R)-4-benzyloxy-5,6-(isopropylidenedioxy)-2-methylenehexanoate with ethyl (R)-5-iodo-3-methylpentanoate performed in the presence of 7 equiv of MgBr2·OEt2. 相似文献
14.
Piotr Pawlu? 《Tetrahedron》2009,65(28):5497-1866
A new efficient synthetic protocol for the highly stereoselective synthesis of unsymmetrical (or symmetrical) (E)-stilbenes and (E,E)-1,4-diarylbuta-1,3-dienes based on sequential palladium-catalyzed Heck arylation-Hiyama cross-coupling reactions using cyclic gem-bis(silyl)ethene as alkenyl building block is reported. 相似文献
15.
K. Raghavendra Rao Akula Raghunadh Ramamohan Mekala Suresh Babu Meruva T.V. Pratap T. Krishna Dipak Kalita Eppakayala Laxminarayana Bagineni Prasad Manojit Pal 《Tetrahedron letters》2014
A dual reactant/catalyst role of glyoxylic acid in the reaction of isatoic anhydride with various amines afforded a novel, robust and rapid synthesis of 3-(un)substituted quinazolin-4(3H)-ones. This metal catalyst-free reaction proceeds via an unusual and unexpected cleavage of C–C bond. A shorter and common route to two alkaloids, that is, rutaecarpine and evodiamine is also accomplished. 相似文献
16.
Reaction of fused 3-(2-bromoethyl)pyrimidin-4(3H)-ones with primary alkylamines gave abnormal fused 3-alkyl-4-alkyliminopyrimidines via a new rearrangement, as well as normal substituted 3-(2-alkylaminoethyl) derivatives. Antidepressive evaluation of these compounds was performed by antireserpine action and one compound exhibited the positive activity comparable to imipramine. 相似文献
17.
Stephen G. Davies Ian A. Hunter Rebecca L. Nicholson Paul.M. Roberts Edward D. Savory Andrew D. Smith 《Tetrahedron》2004,60(35):7553-7577
α-Dibenzylamino- and α-benzyloxy- derivatives of N-acetyl-(S)-4-benzyl-5,5-dimethyloxazolidin-2-one readily undergo highly stereoselective boron mediated syn-aldol reactions with a range of aromatic and aliphatic aldehydes, generating the syn-aldol products in good to excellent yields as single diastereoisomers after purification. In the α-dibenzylamino series, deprotection of the functionalised aldol fragments to the corresponding α-amino-β-hydroxy methyl ester or α-amino-β-hydroxyaldehyde proved problematic, with a range of N- and O-protecting groups giving mixtures of products arising from endocyclic and exocyclic cleavage pathways. However, in the α-benzyloxy series, O-silyl protection of the aldol products, and subsequent DIBAL reduction gives stereoselectively the corresponding N-1′-hydroxyalkyloxazolidin-2-ones, which undergo base promoted fragmentation to the desired highly functionalised and differentially protected α,β-dihydroxyaldehydes in good yields and without loss of stereochemical integrity. 相似文献
18.
N-Phenyl-4-(6-phenylimidazo[2,1-b]thiazol-5-yl)thiazol-2-amines (6a-q) have been synthesized by the Hantzsch thiazole reaction of 2-chloro-1-(6-phenylimidazo[2,1-b]thiazol-5-yl)ethanones (4a-e) with suitably substituted thioureas using microwave heating. The ethanones (4a-e) were prepared by the reaction of 6-phenylimidazo[2,1-b]thiazoles (3a-e) with chloroacetylchloride in refluxing 1,4-dioxane whereas the thiazoles (3a-e) were synthesized by the reaction of 2-bromo-1-phenylethanones (2a-e) with thiazol-2-amine in refluxing acetone. 相似文献
19.
Thermolysis of the mixed-metal cluster PhCCo2MoCp(CO)8 (1) with the diphosphine ligand 2,3-bis(diphenylphosphino)maleic anhydride (bma) in CH2Cl2 leads to the sequential formation of the phosphido-bridged cluster Co2MoCp(CO)5[μ2,η2,η1-C(Ph)CC(PPh2)C(O)OC(O)](μ-PPh2) (3) and the bis(phosphido)-bridged cluster Co2MoCp(CO)4[η3,η1,η1-C(Ph)CCC(O)OC(O)](μ-PPh2)2 (4). 3 and 4 have been isolated and characterized in solution by IR and NMR (1H, 13C, and 31P) spectroscopies, and the solid-state structures have been established by X-ray diffraction analyses. Both clusters contain 48e- and exhibit triangular Co2Mo cores. The structure of 3 reveals the presence of a phosphido moiety that bridges the Co-Co vector and a six-electron μ2,η2,η1-C(Ph)CC(PPh2)C(O)OC(O) ligand that caps one of the Co2Mo faces. The X-ray structure of 4 confirms that the five-electron η3,η1,η1- C(Ph)CCC(O)OC(O) ligand is σ-bound to the two cobalt centers in an η1 fashion and π-coordinated to the molybdenum center through a traditional η3-allylic interaction. The reaction between PhCCo2MoCp(CO)8 and the chiral diphosphine ligand 3,4-bis(diphenylphosphino)-5-methoxy-2(5H)-furanone (bmf) proceeds similarly, furnishing the phosphido-bridged cluster Co2MoCp(CO)5 [μ2,η2,η1-C(Ph)CC(PPh2)C(O)OCH(OMe)](μ-PPh2) (6), followed by conversion to Co2MoCp(CO)4[η3,η1,η1-C(Ph)CCC(O)OCH(OMe)](μ-PPh2)2 (7). The identities of clusters 6 and 7 have been ascertained by solution spectroscopic methods and X-ray crystallography. The overall molecular structure of cluster 6 is similar to that of cluster 3, except that the P-C(furanone ring) bond cleavage occurs with high regioselectivity and high diastereoselectivity. The cleavage of the remaining P-C(furanone ring) bond in cluster 6 gives rise to the bis(phosphido)-bridged cluster 7, whose structure is discussed relative to its bma-derived analogue 4. The diastereoselectivity that accompanies the formation of 6 and 7 is discussed relative to steric effects within the Co2Mo polyhedron. The cyclic voltammetric properties of cluster 3 have been examined, with three well-defined one-electron processes for the 0/+1, 0/−1, −1/−2 redox couples found. The composition of the HOMO and LUMO in 3 was established by extended Hückel MO calculations, with the data discussed relative to the parent tetrahedrane cluster 1. 相似文献
20.
Noriyoshi Kon Nobuhiko Iki Yusuke Yamane Shin Shirasaki Sotaro Miyano 《Tetrahedron letters》2004,45(1):207-211
2,14-Dithiacalix[4]arene 34 was conveniently prepared in 16% yield by acid-catalyzed cyclocondensation of 2,2′-thiobis[4-tert-butylphenol] with formaldehyde. The present method also afforded the first isolation of the analogues with six and eight phenol units, 36 (10%) and 38 (5%), respectively. Solvent extraction showed that 34 had high selectivity toward Cu2+ ion at pH 5.5 by coordination of the bridging sulfur with cooperative donation of the adjacent phenolate oxygens. 相似文献