12 resultados para HETEROCYCLES
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
A mild and efficient copper-catalyzed system for N-arylation of alkylamines and N-H heterocycles with aryl iodides using a novel, readily prepared and highly stable oxime-functionalized phosphine oxide ligand was developed. The coupling reactions could even be performed in solvent-free conditions with moderate to good yields. (c) 2005 Elsevier Ltd. All rights reserved.
Resumo:
Efficient and divergent one-pot synthesis of fully substituted 1H-pyrazoles and isoxazoles from cyclopropyl oximes based on reaction conditions selection is reported. Under Vilsmeier conditions (POCl3/DMF), substituted 1H-pyrazoles were synthesized from 1-carbamoyl, 1-oximyl cyclopropanes via sequential ring-opening, chlorovinylation, and intramolecular aza-cyclization. In the presence of POCl3/CH2Cl2, substituted isoxazoles were obtained from the cyclopropyl oximes via ring-opening and intramolecular nucleophilic vinylic substitution (SNV) reactions
Resumo:
A novel route for the synthesis of a variety of 2-trifluoromethylbenzofurans is reported. By selection of solvents, the key intermediates, 2-chloro-3,3,3-trifluoropropenyl phenyl acetates, were cyclized either to give 2-trifluoromethyl-substituted benzofurans or to yield trifluoromethyl modified o-alkynylphenols. The latter intermediates could also be cyclized to give 3-iodo-2-trifluoromethyl-substituted benzofurans.
Resumo:
A facile and efficient synthesis Of Substituted pyridin-2(1H)-ones has been developed by the reaction of readily available 1-carbamoyl-]-[3-(dimethylamino)propenoyl]cyclopropanes with phosphoryl chloride or phosphorus tribromide in dichloromethane at room temperature.
Resumo:
A facile and practical one-pot synthesis of beta-oxo thioamides from beta-oxo amides has been developed. By treatment with isothiocyanates in ethanol in the presence of potassium carbonate, a series of beta-oxo amides was converted, under reflux, in high yields into the corresponding beta-oxo thioamides.
Resumo:
A convenient and efficient synthesis of highly substituted pyrrolin-4-ones is developed via the PIFA-mediated cyclization reactions of readily available enaminones, and a mechanism involving sequential cleavage of N-C bond, formation of new N-C bond, intramolecular addition reaction, and benzilic acid type rearrangement is proposed.
Resumo:
Four new organotin complexes, namely [(Bu2Sn)(2)O(EtO)(L1)](2) (1), [(Bu2Sn)(2)O(EtO)(L2)](2) (2), [(Bu2Sn)(2)O(EtO)(L-3)](2) (3) and [Ph3Sn(L4)]center dot 0.5H(2)O (4), were obtained by reactions of Bu2SnO and Ph3SnOH with 4-phenylideneamino-3-methyl-1,2,4-triazole-5-thione (HL1), 4-furfuralideneamino-3-methyl-1,2,4-triazole-5-thione (HL2), 4-(2-thienylideneamino)-3-ethyl-1,2,4-triazole-5-thione (HL3) and 4-(3,5-di-t-butylsalicylideneamino)-3-ethyl-1,2,4-triazole-5-thione (HL4). Compounds 1-4 were characterized by elemental analysis, IR spectra and their structures were determined by single-crystal X-ray diffraction methods. Complexes 1-3 show similar structures containing a Sn4O4 ladder skeleton in which each of the exo tin atoms is bonded to the N atom of a corresponding thione-form deprotonated ligand. Complex 4 shows a mononuclear structure in which the tin atom of triphenyltin group is coordinated by the S atom of a thiol-form L4(-) anion.
Resumo:
Reactions of the Rh hydrido complex [Rh(H)(2)(PPh3)(2)(EtOH)(2)]ClO4 (1) With nitrogen ligands such as 2-(4-thiazolyl)benzimidazole (tbz). pyridazine (pdz), imidazole (im) and pyrimidine (pmd) in CH,Cl, afforded Various mononuclear Rh hydrido complexes, [Rh(H)(2)(PPh3)(2)(tbz)]CIO4 (2), [Rh(H)(2)(PPh3)(2)(pdZ)(2)]ClO(4)(.)2CH(2)Cl(2) (3). [Rh(H)Cl(PPh3)(2)(pdz)(2)](ClO4CH2Cl2)-C-. (4). [Rh(H)(2)(PPh3)(2)(im)(2)]ClO(4)(.)2CH(2)Cl(2) (5). [Rh(H)Cl(PPh3)(2)(im)(2)](ClO4CH2Cl2)-C-. (6). [Rh(H)(2)(PPh3)(2)(pmd)(2)](ClO4CH2Cl2)-C-. (7) and the Rh non-hydrido complex [RhCl2(pmd)(4)]ClO4 (8). The Rh complexes 2. 3, 5 and 6 were crystallographically characterized. The formation process was monitored by H-1 NMR and UV-Vis spectra. In all the Rh hydrido complexes, the Rh atom is coordinated by two PPh3. ligands in trans-positions and two nitrogen ligands in the cis-positions. The remaining sites Lire occupied by one or two hydride atoms to form a saturated 18-electron framework in a slightly distorted octahedral geometry. For complex 2 an appreciable inter-molecular pi interaction is observed between planes of tbz and PPh3 ligands, while an intra-molecular hydrogen bonding interaction between C-H and Cl atoms is found in complex 6.
Resumo:
In the title compound, C12H10FN7S, the dihedral angles made by the plane of the thione-substituted triazole ring with the planes of the other triazole ring and the benzene ring are 74.55 (2) and 11.50 (3)degrees, respectively. The structure shows a number of N - H center dot center dot center dot N intermolecular hydrogen-bonding interactions, and weak C - H center dot center dot center dot S intra- and intermolecular interactions.