Heterocyclic Ketones Research Articles

Antimicorbial effects of newly synthesized organotin(IV) and organolead(IV) derivatives

AbstractTriorganotin(IV) and triorganolead(IV) derivatives of the types Me3Sn(SCZ) and Ph3Pb(SCZ) (where SCZ− is the anion of a semicarbanzone ligand) have been synthesized by substitution reactions of trimethyltin chloride and triphenyl‐lead chloride with semicarbazones derived from heterocyclic ketones. The resulting complexes have been characterized by elemental analyses, molecualr weight determinations and conductivity measurements. The mode of bonding has been established on the basis of infrared and 1H, 13C and 119Sn NMR spectroscopic studies. Some respresentative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria; the results of these investigations have been reported in the present paper.

Inclusion complexes of prochiral heterocyclic ketones with ?-cyclodextrins and their reduction with sodium borohydride

Alkyl(2-furyl), alkyl(2-thienyl), and methyl pyridyl ketones form stoichiometric inclusion complexes with β-cyclodextrins. Reduction of these complexes in aqueous solution of Na2CO3 at room temperature yields the corresponding secondary alcohols with an optical yield which attains 27%.

On triazoles XXXI. The reaction of 1,2,4‐triazolylcarbothiohydrazides with homo‐ and heterocyclic ketones. An unexpected reaction leading to 4,5‐polyalkylene thiazoles

AbstractThe reaction of 1,2,4‐triazolylcarbothiohydrazides with homo‐ and heterocyclic ketones to yield 8‐spiro‐[1,2,4]triazolo[1,5‐d][1,2,4,6]tetrazepine‐5‐thiones 7 (n = 4, 5, 6, 7 and 11), 8 and 9, respectively, all representing novel ring systems was studied. Providing the reaction at higher temperature a novel reaction was observed to yield 4,5‐polyalkylene thiazoles for which a mechanism is proposed.

SYNTHESIS, CHARACTERIZATION AND BIOCIDAL EFFECTS OF TRIORGANOLEAD(IV) COMPLEXES DERIVED FROM THIO-LIGANDS

Abstract The substitution reactions of heterocyclic thiosemicarbazones with triphenyllead(IV) chloride in 1:1 molar ratio give Ph3PbL (L = anion of thiosemicarbazone derived from heterocyclic aldehyde or ketone) type of complexes. The elemental analyses, molecular weight determinations, conductivity measurements and spectral (IR, 1H and 13C NMR) studies have been used to elucidate their penta-coordinated structures. Some representative ligands and their metal chelates have also been screened for their antimicrobial effects against different species of pathogenic fungi and bacteria.

Synthetic and biochemical aspects of titanocene- and zirconocene-dichloride chelates of thiosemicarbazones derived from heterocyclic ketones

This communication deals with a brief description of a synthetic procedure and structural characterization of a new class of coordination compounds of titanium and zirconium with sulphur-containing organic moieties derived by the condensation of heterocyclic ketones and thiosemicarbazide. On the basis of various physicochemical and spectral studies, viz., UV, IR, 1H and 13C NMR, a trigonal bipyramidal and octahedral geometries have been suggested for Cp 2M(Tscz)Cl and Cp 2M(Tscz) 2 (where M = Ti(IV) or Zr(IV) and TsczH = ligand molecule) type of compounds, respectively. Finally, attempts have been made to establish a correlation between biological activity and the structures of the resulting products on the basis of different constituents and chemical phenomenon.

The Synthesis of Substituted 2-Aminophenyl Heterocyclic Ketones

Abstract The synthesis of substituted 2-aminophenyl heterocyclic ketones, key intermediates to the preparation of 1,4-benzodiazepines has been achieved in one step and in good, yield from the corresponding anthranilic acid, by treatment with heterocyclic lithium reagents and chlorotrimethylsilane.

ChemInform Abstract: Regioselective Synthesis of Piperidinones by Metal-Catalyzed Ring Expansion-Carbonylation Reactions. Remarkable Cobalt and/or Ruthenium Carbonyl Catalyzed Rearrangement and Cyclization Reactions.

Carbonylation of pyrrolidines, catalyzed by cobalt carbonyl, results in the formation of piperidinones. The reaction is regiospecific in most cases, and the yield of product is increased when ruthenium carbonyl is present as a second catalyst. The dual catalytic system [Co 2 (CO) 8 /Ru 3 (CO) 12 ] is useful for the novel rearrangement of heterocyclic nitrogen ketones ((CH 2 ) n NCH 2 COR, n=4-7] to lactams in 72-93% yields. An unusual metal cataIyzed cyclization reaction of 2,6-dimethylpiperidinyl ketones afforded 5,6,7,8-tetrahydroindolizines in 86-94% yields

SYNTHETIC, STEREOCHEMICAL AND BIOLOGICAL ASPECTS OF ORGANOANTIMONY(III) DERIVATIVES OF THIO-IMINES

Abstract Diphenylantimony(III) derivatives of monobasic bidentate thiosemicarbazones derived from heterocyclic aldehydes and ketones have been synthesized and characterized by elemental analyses, molecular weight determinations and conductance measurements. The stereochemical features of these newly synthesized complexes have been discussed in terms of IR, 1H NMR and 13C NMR spectral data. Some representative ligands and their metal chelates have also been screened for their antifungal activity.

Studies on complexation equilibria between water-soluble hydrazones which consist of 5-nitro-2-pyridylhydrazine and heterocyclic ketones and divalent metal ions

Complexation equilibria between five water-soluble hydrazones which consist of 5-nitro-2-pyridylhydrazine and heterocyclic ketones and divalent metal ions have been studied spectrophotometrically. Equilibrium constants of the complexation reactions and overall formation constants of the resultant complexes have been determined and species of the complexes clarified.

Synthetic and structural aspects of dioxomolybdenum complexes of thiosemicarbazones and semicarbazones

Condensation of the heterocyclic ketones 2-acetyl pyridine, 2-acetyl furan, 2-acetyl thiophene and 2-acetyl indole with thiosemicarbazide or semicarbazide hydrochloride yields the corresponding Schiff bases which, when subsequently reacted with molybdenum acetylacetonate, give addition products of the type [MoO2L2] (where L=Schiff base). The complexes have been characterized by physicochemical and spectroscopic methods.

PHOTOCHEMISTRY IN A CYCLODEXTRIN CAVITY. PRIMARY PROCESSES IN THE PHOTOREDUCTION OF 3‐ and 4‐BENZOYLPYRIDINE STUDIED BY LASER FLASH‐PHOTOLYSIS*

AbstractThe photochemistry of 3‐ and 4‐benzoylpyridine‐cyclodextrin inclusion complexes (BPyCDx) was examined by nanosecond laser flash‐photolysis and stationary techniques. The lifetimes of the triplet complex and of the triplet radical pair, formed by H‐abstraction from a glucose unit of the CDx, have been measured in β‐CDx complexes. The reactivity of the heterocyclic ketones with CDx is higher than that of benzophenone, but the lower binding ability of the macrocycle toward these more hydrophylic molecules induces faster separation of the geminate radicals. The quantum yields of the escaped radicals and their decay kinetics have been determined. The β‐CDx cage favours geminate recombination reactions, while α‐ and ‐γ‐CDx tend to release the guest molecule. Cage products have been spectroscopically characterized in the case of the 3‐BPy‐β‐CDx system.

SYNTHETIC PATHWAYS, STRUCTURAL FEATURES AND BIOCHEMICAL APPLICATIONS AS STERILIZING AGENTS OF SOME DIPHENYLSILICON(IV) CHELATES WITH N⌢SH SYSTEM

Abstract The synthesis and structural features of some diphenylsilicon(IV) complexes with biologically active organic moieties derived by the condensation of heterocyclic ketones with thiosemicarbazide have been described. The newly resulting products of the types Ph2Si(N⌢S)Cl and Ph2Si(N⌢S)2 were obtained by the 1:1 and 1:2 stoichiometric interactions of diphenyldichlorosilane with the Na-salts of sulfur donor ligands (N⌢SH) in anhydrous methanol. The penta- and hexa- coordinated environment around the silicon(IV) ion have been assigned on the basis of electronic, IR, 1H NMR and 13C NMR spectral studies as well as physicochemical techniques including molecular weight determinations and conductance measurements. The results of two silicon(IV) complexes along with one ligand as a sterilizing agent on male-mice have also been produced and tried to correlate with the structures of the chelates.

A FACILE SYNTHESIS OF THIOSEMICARBAZIDESAND THIOSEMICARBAZONES BY THETRANSAMINATION OF 4-METHYL-4-PHENYL-3-THIOSEMICARBAZIDE

Abstract Thiosemicarbazones of α-(N)-heterocyclic ketones and aldehydes possess a broad spectrum of potentially useful chemotherapeutic activities. Thus, the antimalarial, antibacterial, and antiviral properties of this class have been explored by Klayman, et al.1 The antileishmanial activity of a series of acetyl β-carboline thiosemicarbazones was recently described by Dodd and coworkers .2 The α-(N)-heterocyclic thiosemicarbazones act as tridentate ligands for transition metals3; this property has been implicated in their biological mechanism of action.4 The synthesis thiosemicarbazone-transition metal complexes and the spectroscopic investigation of structure and bonding in these complexes is being actively pursued 5 In order to facilitate these investigations, an improved method of synthesizing thiosemicarbones is desirable. Such a synthesis should be efficient (high yield), general (afford thiosemicarbazones of N4-monosubstitution or N4,N4-disubstitution patterns), safe (avoids toxic or unpleasant re...

Hydroboration. 86. Convenient conversion of aldehydes and ketones into the corresponding alkenes via hydroboration of their enamines. A remarkably simple synthesis of either (Z)- or (E)-alkenes

Aldehydes and ketones are converted into the corresponding alkenes via hydroboration of their enamines. Hydroboration of aldehyde enamines by 9-borabicyclo [3.3.1] nonane (9-BBN), followed by methanolysis, affords the corresponding terminal alkenes in 75-90% yields. Unsaturated aldehyde enamines produce the corresponding dienes under these conditions. Enamines derived from substituted cyclic ketones and heterocyclic ketones are readily accommodated in this reaction to afford the corresponding alkenes in very good yields. The synthesis of pure (Z)- or (E)-alkenes is readily achieved from the same acyclic ketone enamine by modification of the hydroboration-elimination procedure: (A) hydroboration by 9-BBN followed by methanolysis or (B) hydroboration by borane methyl sulfide (BMS) followed by methanolysis and hydrogen peroxide oxidation. Mechanistic rationale is provided

Reinvestigation of heterocyclic structures: Oxidation products from 1-substituted 2,4,6-triphenylpyridinium salts

Ferricyanide oxidation of pyridinium salts Ia, Ib leads to mixture of isomeric heterocyclic ketones IIa, IIb and IVa, IVb, respectively. Crystal and molecular structures of the products IIb and IVb were determined by X-ray diffraction analysis. Formely presumed formation of heterocyclic systems type of the III type has been corrected.

ChemInform Abstract: The Preparation of Amide Derivatives of the 3‐Azabicyclo(3.3.1)nonanes as New Potential Antiarrhythmic Agents.

AbstractThe heterocyclic ketones (I) are α,α'‐bishydroxymethylated and then directly cyclized with benzylamine (III) to form the bicyclic amines (IV).

Baker's Yeast as a Reagent in Organic Synthesis

This review examines the use of baker's yeast as a reagent in organic synthesis, with an emphasis on the developments of the last 15 years. The transformations of various classes of compounds are examined, for example, reduction or formation of double bonds, acyloin condensation. The equivalent microbial transformations are compared in relevant cases. 1. Introduction 2. Reduction of β-Keto Esters 3. Reduction of other Keto Acid Derivatives 4. Reduction of α-Hydroxy Aldehydes and Ketones to Vicinal Diols 5. Reduction of Ketones with a Sulfur Containing Functional Group on the α-Carbon 6. Reduction of β-Diketones 7. Reduction of Carbon-Carbon Double Bonds 7.1. Preparation of Bifunctional Chiral Synthetic Building Blocks 7.2. Reduction of Trisubstituted Double Bonds of Larger Synthetic Intermediates 7.3. Reduction of other Trisubstituted Double Bonds 8. Formation of Carbon-Carbon Bonds 8.1. Acyloin Condensation 8.2. Enzymatic Cyclization of Squalenoids 8.3. Carbon-Carbon Bond Formation through Michael-Type Addition 9. Reduction of Carbonyl Groups for the Preparation of Optically Active Fluorinated Compounds 10. Reduction of Heterocyclic Ketones 11. Reduction of Aromatic and Unsaturated Ketones 12. Kinetic Resolution of Cyclic Racemic Ketones 13. Reduction of Nitro Containing Compounds 14. Ester Hydrolysis 15. Water Addition Across the Double Bond of α,β-Unsaturated Aldehydes 16. Dehydrogenation of Unnatural Fatty Acids

Palladium-catalyzed acyldemetallation and carbonylation reactions of organomercurials for the synthesis of unsymmetrical ketones

The palladium-catalyzed acyldemetallation reactions of organomercurials (R 2Hg or AlkHgI) provide a mild, selective, and general method for the synthesis of unsymmetrical heterocyclic ketones. High yields of ketones (RCOR′) were obtained along with small amounts of homocoupling products (R 2). The reaction is accelerated by a nucleophilic catalyst with both organic groups of R 2Hg taking part in the reaction. The selectivity of the reaction towards the ketone can be increased by carrying out the reaction with a suitable combination of reactants under vacuum. The palladium-catalyzed carbonylation of organomercurials in the presence of ArI is another route to unsymmetrical ketones. The AlkHgIArI system undergoes carbonylation in the presence of palladium complex and excess of iodide ion under mild conditions to give high yields of unsymmetrical ketones. The selectivity and rate of the reaction depend upon the nature of the catalyst, solvent, and the concentration of iodide ion.

Carbonyl Radical Cyclizations: Preparation of Some Heterocyclic Ketones

Carbonyl Radical Cyclizations: Preparation of Some Heterocyclic Ketones

Asymmetric catalysis: XL. Enantioselective hydrosilylation of ketones by diphenylsilane with [Rh(cod)Cl] 2/pyridinethiazolidine catalysts

Fiftyeight prochiral ketones have been used inenantioselective hydrosilylation with diphenylsilane promoted by in-situ catalysts consisting of [Rh(cod)Cl] 2 and the chiral ligands (4 S-2-methyl-2-(2-pyridyl)-4-carbomethoxy-1,3-thiazolidine ( A) and (4 S)-2-(2-pyridyl)-4-carbethoxy-1,3-thiazolidine ( B). Hydrolysis of the silyl ethers gave the corresponding secondary alcohols. Aryl methyl ketones were reduced with ee's better than 80% irrespective of whether the substituents Me, Cl, F, OMe were in o-, m-,. or p-position of the phenyl ring. The only exceptions were ketones containing the p-OMe substituent, for which a “ p-methoxy effect” diminished the optical yields. Heterocyclic ketones were also hydrosilylated with high optical inductions, e.g. 2-acetylpyridine with 88.5% ee. Linear alkyl ketones with the CO group in the 2-position (methyl ketones) gave up to 50% ee R, in contrast to the corresponding ethyl ketones with the CO group in 3-position, which gave predominantely S-configurated products. In 35 cases the asymmetric inductions were higher with ligand B than with ligand A.