Reactivity of [m]ferrocenophanones: The aldol condensation

1986 ◽  
Vol 51 (5) ◽  
pp. 1112-1118 ◽  
Author(s):  
Pavol Elečko ◽  
Štefan Toma ◽  
Miroslav Vrúbel ◽  
Eva Solčániová
Keyword(s):  
Carbonyl Group ◽  
Aldol Condensation ◽  
Basic Medium ◽  
Unsaturated Ketone ◽  
Cyclic Ketones ◽  
Unsaturated Ketones

Investigation of the reaction of [m]ferrocenophanones with p-chlorobenzaldehyde in basic medium showed that these cyclic ketones are much more reactive than their acyclic counterparts. The size of the bridge and the position of the carbonyl group influenced the reaction. Thus, [m]ferrocenophan-1-ones (m =3,4 afforded β-hydroxyketones only, [5]ferrocenophan-1-one gave in addition an α,β-unsaturated ketone, and [4]ferrocenophane-2-one yielded only α,β-unsaturated ketones. Oxidation of [m]ferrocenophanes with MnO2 furnished the expected monoketones and [4]ferrocenophane-1,4-dione and [5[ferrocenophane-1,2-dione. The preparation of [5]ferrocenophane-1,5-dione was also improved.

scholarly journals An Expeditious and Safe Synthesis of Some Exocyclic α,β-Unsaturated Ketones by Microwave-Assisted Condensation of Cyclic Ketones with Aromatic Aldehydes over Anhydrous Potassium Carbonate

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Rina Mondal ◽  
Tapas K. Mandal ◽  
Asok K. Mallik
Keyword(s):  
Microwave Irradiation ◽  
Potassium Carbonate ◽  
Anhydrous Potassium Carbonate ◽  
Aldol Condensation ◽  
Aromatic Aldehydes ◽  
Solvent Free ◽  
Unsaturated Ketone ◽  
Cyclic Ketones ◽  
Unsaturated Ketones ◽  
Microwave Assisted

A rapid, efficient, and solvent-free methodology for synthesis of exocyclic α,β-unsaturated ketones of the categories E-3-arylidene-4-chromanones, E-2-arylidene-1-tetralones, E-2-arylidene-1-indanones, E-3-cinnamylidene-4-chromanones, E-2-cinnamylidene-1-tetralones, E-2-cinnamylidene-1-indanones, α,α′-(E,E)-bis(arylidene)-cycloalkanones, and α,α′-(E,E)-bis(cinnamylidene)-cycloalkanones has been developed through cross-aldol condensation of the constituent cyclic ketones and aldehydes by microwave irradiation over anhydrous potassium carbonate. However, for condensation of 1-thio-4-chromanones with aromatic aldehydes by this method, the initially formed exocyclic α,β-unsaturated ketone has been found to undergo isomerization yielding 3-(arylmethyl)thiochromones.

Potassium fluoride catalyzed reactions between malononitrile and α, β-unsaturated ketones

1970 ◽  
Vol 48 (19) ◽  
pp. 3064-3075 ◽  
Author(s):  
J. W. ApSimon ◽  
J. W. Hooper ◽  
B. A. Laishes
Keyword(s):  
Carbonyl Group ◽  
Structure Elucidation ◽  
Potassium Fluoride ◽  
Knoevenagel Reaction ◽  
Unsaturated Ketone ◽  
Unusual Structure ◽  
Unsaturated Ketones ◽  
Condensation Products ◽  
Intramolecular Condensation ◽  
Catalyzed Reactions

The preparation and structure elucidation of the condensation products between malononitrile and a variety of α,β-unsaturated ketones using potassium fluoride as catalyst is described. If the carbonyl group of the α,β-unsaturated ketone is hindered, then Michael addition occurs. If, however, the carbonyl group is unencumbered, a Knoevenagel reaction appears to occur first which, in many cases, is then followed by conjugate addition and intramolecular condensation to yield compounds of unusual structure.

scholarly journals Stereochemical Peculiarities of the Products of Condensation of Piperidine-4-one with Aromatic Aldehydes

2016 ◽  
Vol 18 (2) ◽  
pp. 111
Author(s):  
M.A. Ospanov ◽  
M.Zh. Turmukhanova ◽  
Zh.A. Abilov ◽  
Peter Langer
Keyword(s):  
Carbonyl Group ◽  
Aldol Condensation ◽  
Resonance Assignments ◽  
Aromatic Aldehydes ◽  
Intermediate Compound ◽  
Nmr Resonance Assignments ◽  
Axial Position ◽  
Unsaturated Ketones ◽  
Alkaline Agent ◽  
C Nmr

<p>This paper presents the results of investigations on conformation peculiarities of the condensation products of piperidine-4-ones containing arylidene, hydroxyarylmethyl as well as both arylidene and hydroxyarylmethyl substituents. Synthesized α, β-unsaturated ketones can be used to investigate conformation of cycles fixing a conjugated system of carbonyl and double bonds. Synthesis of α, β-unsaturated piperidine-4-ones was carried out according to the reaction of Claisen-Schmidt by condensation of piperidine-4-ones with aromatic aldehydes. The reaction was carried out in methanol medium in the presence of an alkaline agent. High resolution <sup>1</sup>H and <sup>13</sup>C NMR resonance assignments and conformational assignments were carried out for four 3- arylidene or hydroxyarylmethyl and 3-arylidene-5- hydroxyarylmethyl substituted piperidine-4-ones (1-4). As a result of the initial aldol condensation of piperidine-4-ones with aromatic aldehydes an aryloxymethyl group in the intermediate compound can have both an equatorial and axial position. Conformation of a conjugated system proved to be electronically effected by the presence of nitrogen atom in the heterocycle. At the same time, conformation peculiarities of α, β-unsaturated ketones under study are developed at the stage of their synthesis. This is explained by the fact that in the course of the reaction there appears a new sp2-centre, this resulting in our case in the change of the conformation of “a chair”. There takes place flattening of the structure and fixation of s-cis conformation. Furfurilidene substituent is conjugated with a carbonyl group, there forms a planar structure including 2, 3, 4 and 5 atoms of hydrogen of piperidine cycle and furfurilidene substituent and there exist two isomers with cis- (A) and trans- (B) position of a furyl ring at double bond in relation to a carbonyl group.</p>

Mechanism of interference with the Jaffé reaction for creatinine.

1987 ◽  
Vol 33 (7) ◽  
pp. 1129-1132 ◽  
Author(s):  
M H Kroll ◽  
N A Roach ◽  
B Poe ◽  
R J Elin
Keyword(s):  
Carbonyl Group ◽  
Equilibrium Constants ◽  
Molar Absorptivity ◽  
Reaction Products ◽  
Cyclic Ketones ◽  
Common Structure ◽  
Aliphatic Ketones ◽  
Rate Of Reaction ◽  
The Common

Abstract We investigated the mechanism of the Jaffé reaction for determination of creatinine by studying the spectrophotometric, kinetic, and equilibrium properties of the reaction of picrate with creatinine and with cyclic and aliphatic ketones. Absorbance spectra for the reaction products of picrate with all the ketones were superimposable with that of creatinine (Amax, 490 nm). Cyclic ketones not containing nitrogen had a molar absorptivity less than half that of creatinine and equilibrium constants approximately 0.01 that of creatinine. Aliphatic ketones, except for benzylacetone, had molar absorptivities similar to that of creatinine, but all of these compounds had equilibrium constants approximately a tenth or less that of creatinine. The common structure for all of the compounds reacting with picrate is the carbonyl group. The variable magnitude of interference for aliphatic and cyclic ketones is ascribable to the different rate constants, molar absorptivities, and equilibrium constants as compared with creatinine. Structures adjacent to the carbonyl group significantly affect the absorptivity and equilibrium constant, but steric hindrance is the major factor affecting the rate of reaction. We postulate that the carbonyl group is required for the Jaffé reaction, and we suggest a mechanism for the reaction.

STUDIES ON LIGNIN AND RELATED COMPOUNDS.: VIII. A KINETIC STUDY OF THE ACTION OF SULPHUROUS ACID ON LIGNIN AND RELATED COMPOUNDS

1931 ◽  
Vol 5 (1) ◽  
pp. 1-47 ◽  
Author(s):  
Charles A. Sankey ◽  
Harold Hibbert
Keyword(s):  
Carbonyl Group ◽  
Addition Product ◽  
Heterocyclic Ring ◽  
Acid Group ◽  
Cyclic Ketones ◽  
Reactive Group ◽  
Experimental Conditions ◽  
Commercial Process ◽  
The Stability ◽  
Related Compounds

Electrical conductivity measurements have been made over the temperature range 18–145 °C. of reaction mixtures of sulphurous acid and a large number of type compounds, and data obtained on the stability of the resulting sulphonic acids and the mobility of the equilibria involved. The compounds investigated include saturated and unsaturated aldehydes; saturated, unsaturated and cyclic ketones; phenols; substances in which an ethylene linkage is the only reactive group; furane derivatives; and substances containing pyrone rings.The results are discussed from the standpoints of structure and reaction mechanism. The sulphonic acids of nuclear aldehydes, saturated ketones and cylic ketones are typically unstable. With compounds containing an ethylene linkage conjugated with a carbonyl group, addition normally takes place in the 1:4 positions and is followed by hydrogen migration. Where an ethylene linkage is the only reactive group present, addition proceeds only very slowly and at high temperatures. The difficulty of effecting a reaction between sulphurous acid and phenols in their tautomeric alicyclic forms is indicated by the non-reactivity of resorcinol, and the formation of only a small percentage of an extremely unstable derivative by phloroglucinol. Furfuryl alcohol and glucal are shown to form oxonium derivatives which serve as intermediates for the entry of the sulphonic acid group into the ring system.Conductivity-temperature curves for lignosulphonic acids from various sources indicate that the products are sulphonic acids of the —C = C—type. Other evidence points to an oxonium addition product with a ring oxygen as being a probable intermediate in the formation of the final and more stable lignosulphonic acid. The relation of such a mechanism to the experimental conditions employed in the commercial process of the manufacture of sulphite pulp is indicated.The formation of lignosulphonic acids through tautomerization of a phenolic nucleus is highly improbable. Also for such formation a carbonyl group does not necessarily have to be present. Strong additional evidence is presented for the presence of a heterocyclic ring containing oxygen and for an ethylene linkage in the lignin molecule. The latter is indicated to be in the same ring system as the oxygen atom.

Terpenoid chemistry. XVII. ( - )-Ngaoine, a toxic constituent of Myoporum deserti. The absolute configuration of ( - )-Ngaione

1970 ◽  
Vol 23 (1) ◽  
pp. 107 ◽  
Author(s):  
BF Hegarty ◽  
JR Kelly ◽  
RJ Park ◽  
MD Sutherland
Keyword(s):  
Essential Oil ◽  
Essential Oils ◽  
Plant Material ◽  
Sodium Acetate ◽  
Active Form ◽  
Optically Active ◽  
Unsaturated Ketone ◽  
Unsaturated Ketones ◽  
Chemical Race ◽  
Toxic Constituent

Varieties of the shrub Myoporum deserti A. Cunn. (Ellangowan poison bush), which causes heavy losses of stock in inland Australia, yield at least nine different essential oils, most of which are toxic. One oil from plant material of the Longreach chemical race from Blackall, Clermont, Hannaford, Longreach, Meandarra, Moree, and Roma contains the toxic furanoid sesquiterpene ketone, (-)-ngaione, as the principal constituent while two others (the Mitchell and the Blackall races) contain lesser proportions of ngaione. (-)-Ngaione comprises over half of the essential oil of a "greenish leaf" variety of Eremophila latrobei F. Nuell. and a low proportion of the oil of a "silver leaf" variety of the same species. The trans isomer of ngaione [(-)-epingaione], present in low concentration in some of these essential oils, is formed from ( -)-ngaione during fractional distillation or more rapidly by base-catalysed epimerization. "Isongaione acetate" prepared from (-)-ngaione by treatment with acetic anhydride-sodium acetate is shown to be a mixture of a, β- and β, γ-unsaturated ketones and obtainable in optically active form contrary to literature statements. Oxidation of the optically active β,γ-unsaturated ketone yields (-) acetylmalic acid from which it follows that (-)-ngaione is l(S),4(R)-β-(4,8-dimethyl-6-oxo-1,4-epoxynonyl)furan, ipomeamarone is the 1(R),4(S) enantiomer, and (-)-epingaione is the 1(S),4(S) isomer.

scholarly journals Characterization of Highly Reductive Modification of Tetracycline D-Ring Reveals Enzymatic Conversion of Enone to Alkane

2021 ◽  
Author(s):  
Qiu-Yue Nie ◽  
Zhen-Yu Ji ◽  
Yu Hu ◽  
Gong-Li Tang
Keyword(s):  
Oxidative Modification ◽  
Unsaturated Ketone ◽  
Type Ii ◽  
Enzymatic Conversion ◽  
Unsaturated Ketones ◽  
Isotope Incorporation ◽  
Aureolic Acid ◽  
Post Modification ◽  
Enzymatic Mechanisms

Abstract Tetracyclines are an eminent family of type II polyketides which possess a variety of decoration on the skeletons. However, apart from the oxidative modification in aureolic acid compounds, there are few cases on the further conversion of α, β-unsaturated ketones in the tetracycline D-ring. Here, we identified two reductases (TjhO5 and TjhD4) that highly reduced the α,β-unsaturated ketone of D-ring in the biosynthesis of unconventional tetracyclines. By identifying related intermediates and conducting isotope incorporation experiments, we demonstrated that the entire transformation could be accomplished by TjhO5 and TjhD4 collectively via two distinct pathways involving different enzymatic mechanisms. A distinctive deoxygenation mechanism was possibly involved in the TjhO5-mediated continuous reduction of C = O to CH2. These findings highlight the unprecedent post-modification of tetracyclines and facilitate further engineering to enrich the structural diversities.

scholarly journals Hydrotalcite-Supported Ag/Pd Bimetallic Nanoclusters Catalyzed Oxidation and One-Pot Aldol Reaction in Water

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1120
Author(s):  
Sangita Karanjit ◽  
Ayumu Tamura ◽  
Masaya Kashihara ◽  
Kazuki Ushiyama ◽  
Lok Kumar Shrestha ◽  
...  
Keyword(s):  
Aldol Condensation ◽  
Chemical Reduction ◽  
Recovery Process ◽  
Alcohol Oxidation ◽  
Significant Loss ◽  
One Pot ◽  
Unsaturated Ketones ◽  
Highly Active ◽  
Bimetallic Nanoclusters ◽  
Transmission Electron

A highly active hydrotalcite-supported Ag/Pd bimetallic nanocluster catalyst has been developed by a simple, easy and safe chemical reduction method. The catalyst was characterized by high-resolution transmission electron microscopy (HR-TEM), which revealed very small (3.2 ± 0.7 nm) nanoclusters with a narrow size distribution. The bimetallic Ag/Pd catalyst showed strong cooperation between Ag and Pd for the alcohol oxidation reaction. The developed catalyst provided an efficient and environmentally friendly method for alcohol oxidation and one-pot cross-aldol condensation in water. A broad scope of α,β-unsaturated ketones with good to excellent yields were obtained under very mild conditions. This catalytic system offers an easy preparation method with a simple recovery process, good activity and reusability of up to five cycles without significant loss in the catalytic activity.

IONIZATION OF ORGANIC COMPOUNDS IN ACID I. ALIPHATIC KETONES

1960 ◽  
Vol 38 (11) ◽  
pp. 2109-2116 ◽  
Author(s):  
H. J. Campbell ◽  
J. T. Edward
Keyword(s):  
Sulphuric Acid ◽  
Carbonyl Group ◽  
Absorption Spectra ◽  
Organic Compounds ◽  
Acid Strength ◽  
Medium Effect ◽  
Ring Size ◽  
Cyclic Ketones ◽  
Aliphatic Ketones ◽  
Weak Peak

The changes in the ultraviolet absorption spectra of aliphatic ketones in aqueous sulphuric acid have been followed as the acid strength is increased from 0 to 98%. With increase in strength up to 65% the weak peak at about 270 mμ is shifted to shorter wavelengths by a medium effect. However, with further increase in acid strength the peak disappears altogether because of protonation of the carbonyl group. The pKBH+ values of several ketones have been calculated from the spectrophotometric results to be about −7. The pKBH+ values of cyclic ketones vary systematically with ring size. The significance of the present work to recent studies on the rate of enolization of acetone is discussed.

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