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Information on the geometrical structures of alpha-(p-phenylsulfinyl)-p-substituted acetophenones X-PhC(O)CH2S(O)Ph-Y [X = OMe, Y = H (1); X = NO2, Y = OMe (2); X = OMe, Y = NO2 (3); IUPAC names: (1) 4-methoxyphenyl phenylsulfinyl...
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Information on the geometrical structures of alpha-(p-phenylsulfinyl)-p-substituted acetophenones X-PhC(O)CH2S(O)Ph-Y [X = OMe, Y = H (1); X = NO2, Y = OMe (2); X = OMe, Y = NO2 (3); IUPAC names: (1) 4-methoxyphenyl phenylsulfinylmethyl ketone; (2) 4 - nitrophenyl 4-methoxyphenylsulfinyl-methyl ketone; (3) 4-methoxyphenyl 4-nitrophenyl-sulfinylmethyl ketone] have been obtained from X-ray diffraction analyses. A comparison of these results with those previously obtained from X-ray diffraction and ab initio computations of alpha-methylsulfinylacetophenone, PhC(O)CH2S(O)Me, indicated that (1) and (2) adopt in the crystal a cis(1) conformation and (3) assumes a quasi-gauche geometry. The stabilization of these conformations in the crystal is discussed in terms of the dipole moment coupling Coulombic and intramolecular charge transfer interactions between the oppositely charged atoms of the C=O and S=O dipoles. The p-substituted benzene ring is quasi-coplanar with the sulfinyl group for (1) and (3), but is quasi-perpendicular for (2), Conjugation and repulsion between the sulfinyl sulfur lone pair and the pi-benzene ring seem to be responsible for the observed geometries. [References: 13]
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Multi-substituted quinolines 3 were unexpectedly prepared from a cascade reaction of ortho-azido-β-nitro-styrenes with various carbonyl compounds. This method takes advantages of mild condition, simple work-up, high yield as well...
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Multi-substituted quinolines 3 were unexpectedly prepared from a cascade reaction of ortho-azido-β-nitro-styrenes with various carbonyl compounds. This method takes advantages of mild condition, simple work-up, high yield as well as wide substrate scope, which makes this method powerful for one-pot synthesis of multi-substituted quinolines.
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The Pd-catalyzed cross coupling of either #alpha#-haloenones with organometals or #alpha#-metalloenones with organic halides in intrinsically more problematical than the corresponding reaction of #beta#-substituted enones or ordin...
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The Pd-catalyzed cross coupling of either #alpha#-haloenones with organometals or #alpha#-metalloenones with organic halides in intrinsically more problematical than the corresponding reaction of #beta#-substituted enones or ordinary alkenyl derivatives. Nonetheless, satisfactory procedures have been developed for cross coupling with organometals containing Zn, Sn, B and Cu to give #alpha#-organylenones in high yields. As in the other cases, organozincs generally display the highest reactivity. In highly demanding and/or delicate situations, some indirect protocols involving protection of carbonyl groups or their temporary reduction help overcome difficulties encountered in direct #alpha#-substitution. Conjugate reduction and conjugate addition of #alpha#-substituted enones provide the corresponding saturated carbonyl compounds in completely regiocontrolled manner. Together with the ability to accommodate unsaturated organic groups, such as aryl, alkenyl, and alkynyl, the new Pd-catalyzed #alpha#-substitution protocols developed since 1987 promise to become synthetic tools of widespread application.
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The dinuclear phosphido-bridged molybdenum complexes [(CO)_4Mo(#mu#-PR_2)_2Mo(CO)_4][R=Ph or Me) react with P(n-Bu)_3 to give the corresponding mono and bis-phosphine derivatives.A kinetic study of the first substitution in decali...
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The dinuclear phosphido-bridged molybdenum complexes [(CO)_4Mo(#mu#-PR_2)_2Mo(CO)_4][R=Ph or Me) react with P(n-Bu)_3 to give the corresponding mono and bis-phosphine derivatives.A kinetic study of the first substitution in decalin indicates a CO-dissociative mechanism involving the coordinatively unsaturated intermediate [(CO_4)Mo(#mu#-PR_2)_2Mo(CO)_3].The overall substitution rate depends on the rate of CO dissociation,k_1,and on the rate of bimolecular attack by CO,k_(-1),and by P(n-Bu)_3,k_2,on the reactive intermediate.The nature of the substituents at the phosphido bridge markedly affects the value of k_1,which is higher for the phenyl compared with the methyl group.This is mainly due to a lower activation enthalpy (#DELTA#_1~*=125(Ph)versus 141 (Me)kJ mol~(-1)),which may reflect a weakening of the Mo-CO bond in the presence of a more electron-withdrawing ligand in trans position.The values of the competition rate ratio k_(-1)/k_2,always largely greater than unity,show that attack of the small CO is favoured with respect to the large P(n-Bu)_3;this suggests that the steric crowding observed on the molecular structure of the starting seven-coordinate complexes should play an important role also on the reactivity of their six-coordinate intermediates.
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Paroxetine is a potent inhibitor of serotonin reuptake and is widely prescribed for the treatment of depression and other neurological disorders. The synthesis of paroxetine and the possibility to prepare derivatives with a specif...
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Paroxetine is a potent inhibitor of serotonin reuptake and is widely prescribed for the treatment of depression and other neurological disorders. The synthesis of paroxetine and the possibility to prepare derivatives with a specific substitution pattern that may allow their use as biological probes is an attractive topic especially for medicinal chemists engaged in neurosciences research. Considering the extensive work that was developed in the last decade on the total synthesis of paroxetine, this review summarizes the most important contributions in this field, organized according to the reagent that was used as a starting material. Most of the methods allowed to prepare paroxetine in 4-9 steps with an overall yield of 9-66%. Despite the progress made in this area, there is still room for improvement, searching for new eco-friendly and sustainable synthetic alternatives.
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omega-Aminoacyl and -alkyl derivatives of 4-(dialkylamino)bicyclo[2.2.2]octan-2-amines and of 5-(dialkylamino)-2-azabicyclo[3.2.2]nonanes were prepared and their activities were examined in vitro against the multiresistant K-1 str...
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omega-Aminoacyl and -alkyl derivatives of 4-(dialkylamino)bicyclo[2.2.2]octan-2-amines and of 5-(dialkylamino)-2-azabicyclo[3.2.2]nonanes were prepared and their activities were examined in vitro against the multiresistant K-1 strain of Plasmodium falciparum and against Trypanosoma brucei rhodesiense (STIB 900). The results of the biological tests of the newly synthesized compounds were compared with the activities of already synthesized compounds and of drugs in use. Lots of the newly synthesized compounds showed promising antiprotozoal properties and selectivity, some of them exhibited even higher antiplasmodial activity than chloroquine. Structure-activity relationships were discussed.
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The novel and efficient selenium-catalyzed reductive N-heterocyclization of g-nitro substituted carbonyl compounds with carbon monoxide has been developed. Various multisubstituted 1H-pyrroles can be easily prepared by this protoc...
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The novel and efficient selenium-catalyzed reductive N-heterocyclization of g-nitro substituted carbonyl compounds with carbon monoxide has been developed. Various multisubstituted 1H-pyrroles can be easily prepared by this protocol. The one-pot synthesis of ethyl 1H-pyrrole-3-carboxylate derivatives was also successfully attained by the selenium-catalyzed reaction of b-ketoester, vinyl nitro compounds and carbon monoxide.
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One-pot three-component Kabachnik-Fields synthesis of a-aminophosphonates with high yields from the reaction between carbonyl compound, primary amine, and substituted phosphite can be carried out in a short period, using H-beta ze...
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One-pot three-component Kabachnik-Fields synthesis of a-aminophosphonates with high yields from the reaction between carbonyl compound, primary amine, and substituted phosphite can be carried out in a short period, using H-beta zeolite as a reusable catalyst.
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The catalytic performances of substituted anthraquinones were investigated in catalytic oxidation of alcohols like cyclohexanol, benzyl alcohol and 5-hydroxymethylfurfural (HMF) to carbonyl compounds (cyclohexanone, benzyl aldehyd...
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The catalytic performances of substituted anthraquinones were investigated in catalytic oxidation of alcohols like cyclohexanol, benzyl alcohol and 5-hydroxymethylfurfural (HMF) to carbonyl compounds (cyclohexanone, benzyl aldehyde and diformylfuran). The reduction potential of anthraquinone plays the key role in the oxidation reactions. TOF numbers and selectivities to carbonyl compounds pass through the maximum with increase of the reduction potential. The maximum activity and selectivity ( > 80 %) is observed for sulfonated and carboxylated anthraquinones having intermediate reduction potentials (approximate to 0.1-0.2 V vs SHE). Grafted 2-carboxyanthraquinone catalyst has demonstrated comparable catalytic performance to the parent molecule and might be used as heterogeneous catalyst. The oxidation reaction was found to have radical character with transfer of hydrogen from alcohol to anthraquinone and subsequent oxidation of hydrogenated anthraquinone by oxygen.
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Abstract Chemodivergent (de)hydrogenative coupling of primary and secondary alcohols is achieved utilizing an inexpensive nickel catalyst, (6‐OH‐bpy)NiCl2. This protocol demonstrates the synthesis of branched carbonyl compounds,...
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Abstract Chemodivergent (de)hydrogenative coupling of primary and secondary alcohols is achieved utilizing an inexpensive nickel catalyst, (6‐OH‐bpy)NiCl2. This protocol demonstrates the synthesis of branched carbonyl compounds, α,α‐disubstituted ketones, and α‐substituted chalcones via borrowing hydrogen strategy and acceptorless dehydrogenative coupling, respectively. A wide range of aryl‐based secondary alcohols are coupled with various primary alcohols in this tandem dehydrogenation/hydrogenation reaction. The nickel catalyst, along with KOtBu or K2CO3, governed the selectivity for the formation of branched saturated ketones or chalcones. A preliminary mechanistic investigation confirms the reversible dehydrogenation of alcohols to carbonyls via metal‐ligand cooperation (MLC) and the involvement of radical intermediates during the reaction.
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