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81.
A variety range of functionalized aryl and heteroaryl zinc reagents were efficiently generated by using TMP2Mg·2LiCl (TMP = 2,2,6,6-tetramethylpiperamidyl) in the presence of ZnCl2. The subsequently functionalization gave after reaction with electrophiles the expected polyfunctionalized products in good yields. A detailed study concerned on the point how we found the protocol and how we optimized it was depicted. 相似文献
82.
Reaction of 2,3-diaminopyridine with one equivalent of a functionalised vicinal diketone, in ethanol, yields a series of ligands based upon the pyrido[2,3-b]pyrazine core. The ligands were characterised by 1H, 13C–{1H} NMR, MS and UV–Vis spectroscopy. Reaction of the ligands with one equivalent of {ReBr(CO)5} gave a series of Re-Ln complexes based upon the general formula fac-{ReBr(CO)3(L)} (where L = pyrido[2,3-b]pyrazine-derived ligands, L1–L6). Solution IR studies confirmed the retention of the facially capped, tri-carbonyl coordination geometry at rhenium, and 1H NMR studies confirmed coordination of the ligand to Re(I). EI HR MS data were obtained for each complex confirming the proposed formulation and stoichiometry. Single crystal X-ray structures were obtained for three of the complexes (Re-L1, Re-L2, Re-L6), with each demonstrating that the ligands coordinate to Re(I) in a bidentate manner, via a four-membered chelate ring, which was unsymmetrical in the former two cases. The electronic absorption spectra of the complexes showed absorption into the visible region ca. 375–500 nm, (the complexes are orange-red in appearance). Following irradiation at 350–450 nm, the complexes display a solid-state broad emission peaking between 600–700 nm. The complexes were not sufficiently luminescent in solution to allow further investigation into the origin of this emission band, although with reference to related 1,8-naphthyridine complexes of Re(I) it is likely to incorporate significant 3MLCT character. 相似文献
83.
Substituted 4-amino-1,2,4-triazol-3-ones were synthesized from aldehyde hydrazones and azodicarboxylates in the presence of triphenylphosphine. The cascade reaction was conducted in a single step and the procedure is general and efficient. 相似文献
84.
N-Iodosaccharin (NISac): a new reusable catalyst for formal [2+4] cycloaddition of imines and enones
Ankita Rai 《Tetrahedron letters》2010,51(31):4045-3936
The first example of N-iodosaccharin (NISac)-catalyzed step, pot and atom economic synthesis of 1,3-oxazines via formal [2+4] cycloaddition of imines and enones has been reported. No by-product formation, operational simplicity, ambient temperature and high yields (85-95%) are the salient features of the present synthetic protocol. After isolation of the product, the catalyst NISac can be easily recovered and reused without any loss of efficiency. 相似文献
85.
Synthesis of hitherto unreported benzodiazocine-annulated heterocycles by the implementation of palladium-catalyzed intramolecular Heck reaction has been achieved in excellent yields. 相似文献
86.
Sergey V. Ryabukhin Andrey S. Plaskon Semen S. Bondarenko Oleksandr O. Grygorenko Oleg V. Shishkin 《Tetrahedron letters》2010,51(32):4229-812
Chlorotrimethylsilane-promoted Biginelli-type reaction of ethyl 2,4-dioxo-4-phenylbutanoate, benzaldehyde, and various (thio)ureas is explored. The outcome of the reaction depends on the structure of the (thio)urea used and is strongly affected by the acceptor electronic properties of the COOEt substituent in the molecule of the starting β-dicarbonyl compound. The di- and tetrahydropyrimidine derivatives obtained possess two functional groups with orthogonal reactivity, and thus represent promising building blocks for drug discovery. 相似文献
87.
Cevher Altug Alan K. BurnettEsra Caner Ya?ar DürüstMark C. Elliott Roger P.J. GlanvilleCarol Guy Andrew D. Westwell 《Tetrahedron》2011,67(49):9522-9528
A series of thiazolo[3,2-a]pyridines have been prepared using a multicomponent reaction between aromatic aldehydes, 2-nitromethylenethiazolidine and nitriles containing an active methylene group (malononitrile, ethyl 2-cyanoacetate and 2-phenylsulfonylacetonitrile) in the presence of Et3N under mild conditions with high yields. One of the compounds shows promising anticancer activity across a range of cancer cell lines. 相似文献
88.
Murugulla A. Chari El-Refaie Kenawy B.V. Subba Reddy Ajayan Vinu 《Tetrahedron letters》2010,51(39):5195-5580
Herein we demonstrate for the first time, the synthesis of benzimidazoles through the coupling of aldehydes with o-phenylenediamine by using highly acidic nanoporous aluminosilicate with 3D structure and cage-type pores as the catalyst. The catalyst resulted in excellent yields in short reaction times presumably due to its high acidity, large pore diameter, high surface area, and cage-type 3D porous structure. 相似文献
89.
Summary. Starting from 2-chloro-3-nitropyridine, 1H-pyrido[2,3-b][1,4]thiazin-2(3H)-one was synthesized. This compound was reacted with potassium tert-butoxide and diethyl chlorophosphate to give the intermediate 1H-pyrido[2,3-b][1,4]thiazin-2-ylphosphate derivative, which in turn afforded the 1,2,4-oxadiazolylimidazo[1,5-d]pyrido[2,3-b]pyrazine derivatives. The title compounds are potential ligands for the γ-aminobutyric acid A/benzodiazepine receptor complex.
Corresponding author. E-mail: thomas.erker@univie.ac.at
Received February 22, 2002. Accepted March 6, 2002 相似文献
90.
Kalawati Meena Sudesh Kumari Jitender M. Khurana Amita Malik Chetan Sharma Harsh Panwar 《中国化学快报》2017,28(1):136-142
A simple and efficient three component procedure has been developed for the synthesis of highly substituted spiro[indolo-3,10'-indeno[1,2-b]quinolin]-2,4,11'-triones by one pot three component condensation of enaminones, isatin and indane-1,3-dione in ethanol:water (1:1) in presence of ceric ammonium nitrate (CAN) as catalyst. This method provides several advantages such as lesser reaction time, high yield of products and operational simplicity. The antimicrobial activity of some of the compounds has been investigated against six microbial strains, some of the tested compounds showed good antimicrobial activity. 相似文献