Reactions of α,β-Dibromo-β-nitrostyrenes with Acetylacetone and Ethyl Acetoacetate

The reactions of ,-dibromo--nitrostyrenes with acetylacetone and ethyl acetoacetate were studied. The structures of the products were determined by ¹H NMR, IR, and UV spectroscopy. The products derived from acetylacetone were converted into copper chelates.     

Reaction of dibenzylphosphine oxide with α,β-unsaturated O-methyloximes

The reaction of dibenzylphosphine oxide with O-methyloximes of some ,-unsaturated ketones results in the phosphorylation at the -carbon atom to form methoxyiminophosphine oxides, whereas the reaction of dibenzylphosphine oxide with O-methyloximes of ,-unsaturated aldehydes affords aminodihydrophosphole oxides.     

Synthesis of esters of α-chloroacetoxy-β,β,β,-trichloroethylphosphonic acids

Summary The synthesis of 11 previously unreported dialkyl esters of -mono-, -di-, and -trichloroacetoxy-,,-trichloroethylphosphonic acids has been effected.     

Interaction of α,β-Unsaturated Ketones of the Adamantane Series with N,N'-Binucleophiles

The influence has been established of the structure of the initial ketone, the reactants, and the reaction conditions on the direction of the interaction of ,-unsaturated ketones of the adamantane series with hydrazine, phenylhydrazine, semicarbazide, thiosemicarbazide, urea, and thiourea. It was found that on interaction with hydrazine and phenylhydrazine both intermediate hydrazones and the final cyclization products, pyrazolines, were formed. Reaction with semicarbazide and thiosemicarbazide leads only to the synthesis of derivatives at the carbonyl group, semicarbazones and thiosemicarbazones, but with urea and thiourea leads to products of addition at the double bond.     

Kinetics and mechanism of reaction of cis-α,β-dinitrostilbene with morpholine

Reaction of cis-,-dinitrostilbene (substrate) with morpholine (reagent) in n-hexane leads to cis--nitro--morpholinostilbene (end product). The process is of first order with respect to the substrate and second order with respect to the reagent. Possible reaction mechanisms are analyzed, and it is established that the following are most probable on the basis of kinetic patterns and stereochemistry: development of a charge transfer complex having a hydrogen bond between the substrate nitro group and reagent amino group; reaction of the complex with a second reagent molecule and formation of a carbanion (this stage determines the overall reaction rate); and detachment of a nitrite ion from the nitrocarbanion and its protonation to form the end product.N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. A. N. Nesmeyanov Institute of Heteroorganic Compound, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 78–83, January, 1992.     

Reaction ofβ-arylacryloyloxiranes with phenylhydrazine

The reaction of -arylacryloyloxiranes with phenythydrazine under the conditions of acid catalysis leads to 3 arylvinyl-I-phenylpyrazoles and 2-hydroxymethyl-5-aryl-1,4-pentadien-3-one phenythydrazones.Belorussian State Technological University. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3 pp. 324–327, March, 1996. Original article submitted June 26, 1995.     

Donor-acceptor interaction of p,p′-dimethoxystilbene with α,β-dinitrostilbene

A study was carried out on the interactions of the Z and E forms of the indicated stilbenes in all four possible combinations. Charge transfer complexes are formed and only Z-p,p-dimethoxystilbene converts to its E form.A. N. Nesmeyanov Institute of Organometallic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 210–211, January, 1992.     

Reaction of α,β-unsaturated trifluoromethyl ketones with cyclic enamines

The reactions of ,-unsaturated trifluoromethyl ketones containing aromatic and heteroaromatic substituents with 1-morpholinocyclopentene, 1-morpholinocyclohexene, and 1-methyl-4-morpholino-1,2,5,6-tetrahydropyridine were studied. The reactions proceeded stereospecifically to give the corresponding bicyclo[3.2.1]octane, bicyclo[3.3.1]nonane, and azabicyclo[3.3.1]nonane derivatives.     

Reduction of α,β-unsaturated nitrocompounds with tributyltin hydride.

Nitroalkenes upon treatment with tributyltin hydride in the absence of any catalyst provide a new method for the reduction of α,β -unsaturated nitrocompounds. Oxidative cleavage of the intermediate stannyl nitronates yielded carbonyl compounds in good yields.     

Reactions of β-Sulfinyl α,β-Unsaturated Ketones with Dienes

β-Sulfinyl α,β-unsaturated ketones (2a-f) reacted in a regioselective manner with dienes such as butadiene (3a) and 1,3-pentadiene (3b) to give 1,4-cyclohexadiene derivatives (4-8) with the concomitant elimination of sulfenic acid, while the ketones (2a-c) reacted with cyclopentadiene (3c) to yield the norbornenes (9).     

Reaction of α,β-unsaturated trifluoromethyl ketones with ethyl cyanoacetate

β-Aryl-substituted α,β-unsaturated trifluoromethyl ketones react with ethyl cyanoacetate to give the corresponding Michael addition products, ethyl 3-aryl-2-cyano-6,6,6-trifluoro-5-oxohexanoates, which are formed as mixtures of two diastereoisomers. The reaction time and product yield depend on electron-donating properties of the substituent in the initial ketone. The reaction is not accompanied by intramolecular cyclization of the Michael adducts.     

Reaction of Trialkyl Phosphites with α,β-Unsaturated Carbonyl Compounds

Abstract

Reaction of trialkyl phosphites 1 with α,β-unsaturated oxo-compounds 2 gives oxaphospholenes 3 or/and two types of Arbuzov products, γ-keto-phosphonates 4 and alkyl-enol-ethers 5.     

Reaction of unsymmetrical α,β-unsaturated ketones with thiobarbituric acid

Carbocyclization of unsymmetrical 1,5-diarylpenta-1,4-dien-3-ones with thiobarbituric acid afforded previously unknown 7,11-diaryl-3-thioxo-2,4-diazaspiro[5.5]undecane-1,5,9-triones with high regio- and stereoselectivity. The same spiro compounds were also synthesized by three-component condensation of thiobarbituric acid with the corresponding aromatic aldehydes and 4-arylbut-3-en-2-ones.     

Reaction of 5β,6β-epoxy-16α,17α-cyclohexapregnane with methylmagnesium iodide

On treatment with methylmagnesium iodide, 3β-acetoxy-5β,6β-epoxy-16α,17α-cyclo-hexapregnan-20-one undergoes 3-O-deacetylation along with the opening of the 5β,6β-epoxide ring to form 5α-methyl-6β-hydroxy steroid and the 6α-methyl-6β-hydroxy isomer, the 20-keto group remaining intact.     

Interactions of amphiphilic drugs withα-,β-, andγ-cyclodextrins

The association of several amphiphilic drugs with -, -, and -cyclodextrins has been measured by use of drug-sensitive electrodes. Drugs investigated are hydrochlorides of chlorpromazine, dibucaine, tetracaine, and procaine, and valethamate bromide. Each drug forms the drug:cyclodextrin=11 complex with - and -cyclodextrin, and both the 11 and 21 complex with -cyclodextrin, except valethamate which only forms the 11 complex. The strength of the 11 complex formations is in the order of CyD>-CyD>-CyD. The association constant of the 21 complex in drug--CyD is larger than that of 11 complex. The free energy change of the conplex formation has a positive correlation with that of the micelle formation of drugs. The deviation from this relation is explained in terms of fittability of the bulky hydrophobic group of drugs into the cyclodextrin's cavity. The free energy change for the complex formation between chlopromazine or valethamate and -CyD is governed by the enthalpy term and not by the entropy term which controls the surfactant--CyD interactions.     

Reactions of CH-acids with α,β-unsaturated aldehydes in ionic liquids

Metal carbonate-catalyzed reactions of CH-acids (diethyl malonate, ethyl acetoacetate, ethyl cyanoacetate, and ethyl 2-acetyl- and 2-ethoxycarbonyl-5,9-dimethyldeca-4,8-dienoates) with ,-unsaturated aldehydes (acrolein, crotonaldehyde, citral) were studied in an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF₆], and in a 1-butyl-3-methylimidazolium bromide ([bmim][Br]) — benzene system. The reactions with acrolein and crotonaldehyde afforded Michael addition products, those with citral resulted in Knoevenagel addition products. Sonication increased the yields of the Michael adducts. The ionic liquid [bmim][PF₆] can be recovered and repeatedly used in the reactions.     

Photocatalytic Enantioselective Hydrosulfonylation of α,β-Unsaturated Carbonyls with Sulfonyl Chlorides

This research explores the enantioselective hydrosulfonylation of various α,β-unsaturated carbonyl compounds via the use of visible light and redox-active chiral Ni-catalysis, facilitating the synthesis of enantioenriched α-chiral sulfones with remarkable enantioselectivity (exceeding 99 % ee). A significant challenge entails enhancing the reactivity between chiral metal-coordinated carbonyl compounds and moderate electrophilic sulfonyl radicals, aiming to minimize the background reactions. The success of our approach stems from two distinctive attributes: 1) the Cl-atom abstraction employed for sulfonyl radical generation from sulfonyl chlorides, and 2) the single-electron reduction to produce a key enolate radical Ni-complex. The latter process appears to enhance the feasibility of the sulfonyl radical's addition to the electron-rich enolate radical. An in-depth investigation into the reaction mechanism, supported by both experimental observations and theoretical analysis, offers insight into the intricate reaction process. Moreover, the versatility of our methodology is highlighted through its successful application in the late-stage functionalization of complex bioactive molecules, demonstrating its practicality as a strategy for producing α-chiral sulfones.