共查询到20条相似文献,搜索用时 15 毫秒
1.
For the first time, syntheses of 1,3-diarylbenzo[c]selenophenes are reported involving a selenium transfer reaction of keto-alcohol/benzo[c]furan using Woollins reagent. 相似文献
2.
P. Amaladass 《Tetrahedron》2008,64(34):7992-7998
A series of 1,3-diarylbenzo[c]selenophenes (symmetrical/unsymmetrical) have been synthesized involving a selenium transfer reaction of keto-alcohol/benzo[c]furan using Woollins reagent. The optical and electrochemical studies of these diarylbenzo[c]selenophenes are correlated with their structures. 相似文献
3.
Anna V Gulevskaya Olga V SerdukeAlexander F Pozharskii Denis V Besedin 《Tetrahedron》2003,59(39):7669-7679
N(2)-Oxide and 3-amino derivatives of 6,8-dimethylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-dione have been shown to react with primary alkylamines in the presence of an oxidant to produce condensed imidazolines or imidazoles. Both conversions based on SNH-strategy represent a new approach to imidazoline-(imidazole-)ring annulation. Heterocyclic analogues of the still unknown dibenzo[a,o]pycene were obtained as a by-products of the above transformations upon using of cyclohexylamine. 相似文献
4.
Ming Z. Gao 《Tetrahedron letters》2004,45(29):5649-5652
The novel structures of sulfur-containing chiral bis(oxazoline) compounds which have been synthesized have been determined by X-ray crystal diffraction analyses. A high enantioselectivity (ee >99%) in the asymmetric cyclopropanation of diphenylethene with diazoester using the bis(oxazoline)-Ru(II) catalyst was obtained. 相似文献
5.
Arasambattu K. Mohanakrishnan Natarajan Senthil Kumar P. Amaladass 《Tetrahedron letters》2008,49(32):4792-4795
The synthesis of soluble benzo[c]thiophene analogs capped with 9,9-dialkylfluorene at one end is described. 相似文献
6.
Arasambattu K. Mohanakrishnan J. Arul Clement P. Amaladass V.S. Thirunavukkarasu 《Tetrahedron letters》2007,48(49):8715-8720
The synthesis of 1,3-disubstituted benzo[c]thiophene analogs incorporating benzo[b]thiophene/benzo[b]pyrrole units is described. 相似文献
7.
Spiro[dibenzo[b,i]xanthene-13,3′-indoline]-pentaones and 5H-dibenzo[b,i]xanthene-tetraones are synthesized from the condensation of 2-hydroxynaphthalene-1,4-dione with isatins or aldehydes. 相似文献
8.
A series of novel chiral C2-symmetric bis (oxazoline) ligands have been synthesized.The copper and magnesium complexes,prepared in situ from copper(Ⅱ)-triflate of magnesium triflate with the new enantiopure oxazoline ligands,were evaluated as chiral catalysts in the enantioselective Diels-Alder reaction of cyclopentadiene with N-crotenoyl-oxazolidin-2-one.Primary results showed that diastereoselectivity up to 94% and enantioselectivity up to 68% ee for endo products were observed respectively with these ligands. 相似文献
9.
Shahrzad Abdolmohammadi 《Tetrahedron letters》2007,48(18):3299-3303
Diammonium hydrogen phosphate, (NH4)2HPO4(DAHP), efficiently catalyzes the one-pot, three-component reaction of an aromatic aldehyde, malononitrile and 4-hydroxycoumarin in aqueous media under mild conditions at room temperature, to afford the corresponding dihydropyrano[c]chromenes in high yields. (S)-Proline has also been used as another neutral catalyst for this reaction at reflux. 相似文献
10.
11.
J. Arul Clement 《Tetrahedron》2009,65(21):4113-5670
Synthesis of 1,3-disubstituted benzo[c]thiophene analogs incorporating heterocycles such as benzo[b]thiophene/1-hexylindole/benzo[b]furan and thiophene units is described. Optical and electrochemical studies of the benzo[c]thiophene analogs are also reported. 相似文献
12.
Miki ItoFujiko Konno Takuya KumamotoNoriyuki Suzuki Masatoshi KawahataKentaro Yamaguchi Tsutomu Ishikawa 《Tetrahedron》2011,67(41):8041-8049
Both enantiomers of chelidonine, a B/C-cis-11-hydroxyhexahydrobenzo[c]phenanthridine alkaloid, were synthesized by manipulation of the B/C-dehydro ring juncture of benzo[c]phenanthridine skeleton using Sharpless asymmetric dihydroxylation and stereospecific catalytic hydrogenation after introduction of oxygen functions on the C ring as key reaction steps for the construction of stereogenic centers. 相似文献
13.
Natarajan Senthil Kumar 《Tetrahedron》2010,66(30):5660-5670
Synthesis of 9,9-dialkyl/diarylfluorene based benzo[c]thiophene/benzo[c]selenophenes is presented. The synthesis of benzo[c]thiophene analogs is also realized with fluorene containing one or two thiophene units. The optical and electrochemical studies of fluorenyl benzo[c]heterocycles are correlated with their structures. 相似文献
14.
Vincent Gaumet Emmanuel Moreau Abbass Taleb Johan Neyts Claire Lartigue Olivier Chavignon Alain Gueiffier Jacques Métin 《Tetrahedron letters》2010,51(47):6082-6085
Access to N-protected or N-free imidazo[1,2-a]pyrrolo[3,2-c]pyridine derivatives as potential antiviral compounds was achieved in good yields from N-protected 7-amino-8-halo-2-methylimidazo[1,2-a]pyridines by catalytic coupling of terminal acetylenes under mild conditions using [PdCl2(PPh3)2] or [Cu(Phen)(PPh3)2]NO3. 相似文献
15.
A straightforward synthesis of end-capped bithienyl, quaterthienyl and sexithienyl systems incorporating benzo[c]thiophene units is presented. 相似文献
16.
Niyaz A. Mir Tariq A. Shah Sarfaraz Ahmed M. Muneer Nigam P. Rath Musheer Ahmad 《Tetrahedron letters》2014
A series of imidazo[2,1-b]thiazole and benzo[d]thiazolo[3,2-a]imidazole analogues were synthesized by stirring an equimolar mixture of dibenzoylacetylene with imidazole/thiazole derivatives in toluene or acetonitrile at room temperature. The products were generated in good yields and characterized by standard analytical techniques such as IR, 1H NMR, 13C NMR and mass spectrometry. The structure of products 19, 20, 22, 24 and 25 were also unambiguously confirmed by single crystal X-ray analysis. 相似文献
17.
The synthetic route to and a preliminary biological evaluation of novel indolo[1,2-c]quinazolines (8) and benzimidazo[1,2-c]quinazolines (9) are described. The products were obtained by condensation of the appropriate diamines (e.g. 2-(2-aminophenyl)indole or 2-(2-aminophenyl)benzimidazole) with 2-cyanobenzothiazoles. This work further demonstrates the general applicability of microwaves for a facile and rapid access to original heterocycles with potential pharmaceutical value. 相似文献
18.
Synthesis of 6,7-dihydro-5H-dibenzo[c,e]azepines and biaryls by palladium-catalyzed Ullmann reaction
A novel palladium-catalyzed Ullmann protocol is described for the synthesis of 6,7-dihydro-5H-dibenzo[c,e]azepines and biaryls. In the presence of Pd(OAc)2 and KOAc, intramolecular or intermolecular Ullmann coupling of aryl halides proceeds efficiently under ligand-free and aerobic conditions to afford the corresponding 6,7-dihydro-5H-dibenzo[c,e]azepines and biaryls in moderate to excellent yields. 相似文献
19.
A new, one-pot and three-component synthesis of 4H-pyrido[1,2-a]pyrimidines, 4H-pyrimido[1,2-a]pyrimidines, and 4H-pyrazino[1,2-a]pyrimidines is described. The reactive 1:1 zwitterionic intermediate, formed by the addition of isocyanides to dialkyl acetylenedicarboxylates, was trapped by N-(2-heteroaryl)amides to yield a ketenimine intermediate, which was cyclized and then rearranged under the reaction conditions to afford the title compounds under mild reaction conditions in good yields. Single-crystal X-ray analysis conclusively confirms the structure of the obtained bridgehead bicyclic 6-6 heterocyclic compounds. 相似文献
20.
In order to develop long-wavelength functionalised oxazine dyes with good water solubility and high photostability for biological applications, a series of novel side-chain functionalised benzo[a]phenoxazinium salts were synthesised and characterised. These polycyclic cationic compounds showed strong fluorescence in ethanol and water (pH 7.4), with an emission wavelengths higher than 637 nm, as well as high quantum yields and moderate Stokes’ shifts. The photostability of the fluorophores synthesised, under irradiation at 419 nm, was good to excellent in ethanol and moderate in water at physiological pH. 相似文献