Search results for "Medicinal chemistry"
showing 10 items of 2264 documents
Effect of a κ1-Bonded-M-1,2,3-triazole (M = Co, Ru) on the Structure and Reactivity of Group 6 Alkoxy (Fischer) Carbenes
2017
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem. 6b02957. NMR data for the synthesized compounds, electrochemical data of azides 2 and 4 (PDF) Computational details and cif files containing crystal data for 3a and 5b (CIF1, CIF2)
Synthesis of Isoxazole and 1,2,3-Triazole Isoindole Derivatives via Silver- and Copper-Catalyzed 1,3-Dipolar Cycloaddition Reaction.
2016
International audience; The CuI-or Ag 2 CO 3-catalyzed [3+2] cycloaddition of propargyl-substituted dihydroisoindolin-1-one (3) with arylnitrile oxides 1a-d (Ar = Ph, p-MeC 6 H 4 , p-MeOC 6 H 4 , p-ClC 6 H 4) produces in good yields novel 3,5-disubstituted isoxazoles 4 of the ethyl-2-benzyl-3-oxo-1-((3-arylisoxazol-5yl)methyl)-2,3-dihydro-1H-isoindole-1-carboxylate type. With aryl azides 2a-d (Ar = Ph, p-MeC 6 H 4 , p-OMeC 6 H 4 , p-ClC 6 H 4), a series of 1,4-disubstituted 1,2,3-triazoles 6 (ethyl-2-benzyl-3-oxo-1-((1-aryl-1H-1,2,3-triazol-4-yl)methyl)-2,3-dihydro-1H-isoindole-1-carboxylates) was obtained. The reactions proceed in a regioselective manner affording exclusively racemic adduc…
Synthesis of a Tetraazido-Substituted 2-Tetrazene from 1,5-Cyclooctadiene and Iodine Azide
1997
In contrast to the addition of iodine azide to cyclooctene (1) or 1,3-cyclooctadiene (5), its reaction with 1,5-cyclooctadiene (12) leads mainly to the surprisingly stable tetraazido-substituted 2-tetrazene 14 The structure of this was established by 15N-NMR studies and an X-ray structural analysis. Treatment of 14 with hydrochloric acid yields the diazido-substituted 9-azabicyclo[3.3.1]nonane 20.
Eight-membered heterocycles with two heteroatoms in a 1,5-relationship of interest in medicinal chemistry
2020
Abstract This review deals with 1,5-diheterocines that exhibited biological properties and covers comprehensively the literature from 2007 to the end of February 2019. Among the six possible heterocyclic systems belonging to the eight-membered rings with two heteroatoms, N, O, and S, five had derivatives showing pharmacological activities: 1,5-diazocines, 1,5-oxazocines, 1,5-thiazocines, 1,5-dioxocins, and 1,5-dithiocins. Instead, literature reported no articles dealing with 1,5-oxathiocins of interest in medicinal chemistry. In addition to uncondensed derivatives, 1,5-diheterocines fused to five- and six-membered carbocycles or heterocycles are covered. Bridged 1,5-diheterocines are covere…
Nucleophilic additions of sodium alkoxides to 4,4-dichloro-1,1-diphenyl- 2-azabuta-1,3-diene
2000
The reaction of some sodium alkoxides with 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene is described. Whereas sodium methoxide, ethoxide or isopropoxide leads to 1,3-bis(alkoxy)- and/or 1,3,4-tris(alkoxy)-2-azabut-2-enes, the sodium salt of ethyl glycolate gives a Δ2-oxazoline. Mechanisms for the formation of these products are proposed.
Desulfurization and ring opening of thiirane induced by tantalocene trihydride complexes: Synthesis, reactivity and X-ray structure of Cp′2Ta(=S)(S-i…
1999
The reaction of the tantalocene trihydride complexes Cp′ 2 TaH 3 1 (Cp′= η 5 -C 5 H 4 t Bu) or Cp″CpTaH 3 1′ (Cp″= η 5 -C 5 H 2 -1,2-Me 2 -4- t Bu) with propylene sulfide was found to proceed via an unprecedented sulfur transfer and regioselective ring opening reaction at once to yield sulfido-thiolato tantalocene complexes Cp′ 2 Ta(S)(S- i Pr) 2a whose structure has been determined by X-ray crystallography or Cp″CpTa(S)(S- i Pr) 2′a . Complex 1 reacts with ethylene sulfide to give Cp′ 2 Ta(S)(S–Et) 2b . The reactivity of 2a towards a variety of electrophilic moities has been investigated: protonation (with HBF 4 ) and alkylation (with MeI) reactions occur at the terminal sulfur ligand, …
Reactions of the hydrofluoroborate salts of open-chain analogues of Reissert compounds with some α,β-ethylenic esters
1999
The reaction of the hydrofluoroborate salt of an open-chain analogue of a Reissert compound with some α,β-ethylenic esters does not give a [4 + 2] cycloadduct, as previously described in the case of ethyl acrylate. The reaction starts with a 1,3-dipolar cycloaddition of a munchnone imine 5c, d. The [3 + 2] cycloadducts 13 evolve via a rearrangement–condensation sequence to give a substituted 2-pyridone derivative 18 or 19. The proposed mechanism has been verified by the isolation and structural X-ray analysis of some compounds of the reaction sequence.
Intermolecular oxidative dehydrogenative 3,3′-coupling of benzo[b]furans and benzo[b]thiophenes promoted by DDQ/H+: total synthesis of shandougenine B
2016
With an excess of a strong acid, 2,3-dichloro-5,6-dicyano-1,4-quinone (DDQ) is shown to promote metal-free intermolecular oxidative dehydrogenative (ODH) 3,3'-coupling of 2-aryl-benzo[b]furans and 2-aryl-benzo[b]thiophenes up to 92% yield as demonstrated with 9 substrates. Based on the analysis of oxidation potentials and molecular orbitals combined with EPR, NMR and UV-Vis observations, the studied reaction is initiated by a DDQ-substrate charge transfer complex and presumably proceeds via oxidation of the substrate into an electrophilic radical cation that further reacts with another molecule of a neutral substrate. The coupling reactivity can easily be predicted from the oxidation potent…
Pot-Economy Autooxidative Condensation of 2-Aryl-2-lithio-1,3-dithianes
2018
The autoxidative condensation of 2-aryl-2-lithio-1,3-dithianes is here reported. Treatment of 2-aryl-1,3-dithianes with n-BuLi in the absence of any electrophile leads to condensation of three molecules of 1,3-dithianes and formation of highly functionalized α-thioether ketones orthothioesters in 51-89% yields upon air exposure. The method was further expanded to benzaldehyde dithioacetals, affording corresponding orthothioesters and α-thioether ketones in 48-97% yields. The experimental results combined with density functional theory studies support a mechanism triggered by the autoxidation of 2-aryl-2-lithio-1,3-dithianes to yield a highly reactive thioester that undergoes condensation wi…
1,3-Dipolar Cycloaddition Reactions of Indan-1-one Enamines across Arylnitrile Oxides Leading to Novel Cyclic Isoxazoline Derivatives
2013
Synthesis of a series of cyclic fused-isoxazolines has been accomplished by regioselective and diastereoselective 1,3-dipolar cycloaddition of 3-methylindan-1-one enamines (1a, 1b, 1c) and 3-phenylindan-1-one enamines (2a, 2b, 2c) to arylnitrile oxides (3d, 3e, 3f, 3g, 3h). The structure of the cycloadducts was elucidated by 1H and 13C NMR spectroscopy. The proposed regio- and stereochemistry of fused-compounds (4) and (5) has also been corroborated by two single-crystal X-ray diffraction studies carried out on 4-methyl-8b-morpholinyl-3-(p-tolyl)-4H-3a,8b-dihydroindeno[2,3-d]isoxazoline (4be) and 3-(p-anisyl)-4-phenyl-8b-pyrrolidinyl-4H-3a,8b-dihydroindeno[2,3-d]isoxazoline (5af) and by mea…