Diastereoselective synthesis of α,β-unsaturated systems

Functionalized Z-vinylic tellurides were used in substitution reactions with lower order cyanocuprates leading to α,β-unsaturated ketones and esters in good yields. In the case of acyclic tellurides, the product was obtained in high diastereoselectivity. The control of the stereoselectivity was achieved by simple change of the reaction temperature.     

An improved preparation and a new application of trichloromethylcarbinols from enolizable ketones

We report an improved method for the preparation of trichloromethylcarbinols from enolizable ketones. Trichloromethylcarbinols were obtained in good to excellent yields by using of a combination of CHCl₃, n-BuLi, and chlorotitanium (IV) triisopropoxide. Hydrolysis of the trichloromethylcarbinol to an α,β-unsaturated ester was also explored.     

A facile method for the synthesis of substituted 2-ylidene-1,3-oxathioles from acetophenones

Compounds incorporating 1,3-oxathiole moieties in their frameworks are biologically active. Active methylene ketones can be easily converted to the corresponding dithiocarboxylates by treatment with trithiocarbonate in the presence of sodium hydride. The reactions of aroyl dithiocarboxylates with α-haloketones such as phenacyl bromide or bromoacetone afford substituted 2-ylidene-1,3-oxathioles in good yields.     

Quinoline-pyrimidine hybrid compounds from 3-acetyl-4-hydroxy-1-methylquinolin-2(1H)-one: Study on synthesis,cytotoxicity, ADMET and molecular docking

Some novel 2-amino-6-aryl-4-(4′-hydroxy-N-methylquinolin-2′-on-3′-yl)pyrimidines have been synthesized from α,β-unsaturated ketones of 3-acetyl-4-hydroxy-N-methylquinolin-2-one by reaction of corresponding α,β-unsaturated ketones with guanidine hydrochloride. The purity and structure of the obtained products have been confirmed by thin layer chromatography, IR, ¹H NMR, ¹³C NMR, HSQC, HMBC and MS spectra. All the synthesized of 3-(2-amino-6-arylpyrimidin-4-yl)-4-hydroxy-1-methylquinolin-2(1H)-ones 6a-i were screened for their in vitro cytotoxic activity against human hepatocellular carcinoma HepG2 and squamous cell carcinoma KB cancer lines. Compounds 6b and 6e had the best activity in the series, with IC₅₀ values equal to 1.33 μM. Compounds 6a-g exhibited weak or insignificant activity with liver cancer cell lines HepG2, while compounds 6a and 6g had more powerful activity in this sequence, with IC₅₀ values equal to 47.99 and 89.38 μM, respectively. ADMET properties showed that compounds 6b, 6e, and 6f possessed the drug-likeness behavior. Cross-docking results indicated that two hydrogen bonding interactions in the binding pocket, as potential ligand binding hot-spot residues for compounds 6b and 6e, may be one of the mechanisms of action responsible for the higher cytotoxic effect on HepG2 and KB cells.     

A facile synthesis of 1,7-dicarbonyl compounds via three-component Michael addition reactions

A convenient one-pot synthesis of 1,7-dicarbonyl compounds has been accomplished by a three-component Michael addition reaction of nitromethane with two unsymmetric α,β-unsaturated carbonyl compounds in the presence of a base.     

A new approach for the synthesis of 2-substituted indole derivatives via Michael type adducts

4,7-Dihydroindole undergoes regioselective alkylation at the 2-position of the indole nucleus through conjugate addition with α,β-unsaturated carbonyl compounds. The oxidation of the Michael adducts affords the corresponding 2-substituted indole derivatives which were characterized by spectroscopic methods.     

A new, facile, and protection-free one-pot chemical synthesis of 2′-deoxynucleoside-5′-tetraphosphates

A new straight forward, reliable, and an efficient method for the chemical synthesis of 2′-deoxynucleoside-5′-tetraphosphate is reported. The present ‘one-pot, three step’ synthetic strategy involves the monophosphorylation of nucleoside followed by reaction with tris-(tri-n-butylammonium) triphosphate and hydrolysis of the putative cyclic tetrametaphosphate intermediate to provide the corresponding 2′-deoxynucleoside-5′-tetraphosphate in moderate yield with high purity.     

A new convenient synthesis of N-acyl-2-(dimethoxyphosphoryl)glycinates

Easily accessible N-acyl-2-triphenylphosphonioglycinate tetrafluoroborates react smoothly with trimethylphosphite in the presence of methyltriphenylphosphonium iodide to give N-acyl-2-(dimethoxyphosphoryl)glycinates in good or very good yields. The dimethoxyphosphorylglycinates may be isolated by column chromatography, or used directly for the Wadsworth-Emmons synthesis of α,β-dehydro-α-amino acids in a one-pot procedure without purification.     

A novel synthesis of 5-perfluorophenyl 4,5-dihydro-1H-pyrazoles in THF or water

5-Perfluorophenyl 4,5-dihydro-1H-pyrazoles were synthesized from 1,3-dipolar cycloaddition reaction of perfluorobenyl 2,4,6-triisopropylbenzenesulfonylhydrazone and α,β-unsaturated carbonyl compounds or acrylonitrile in THF or water. It was worthy to note that better results were obtained when water was employed as the solvent, which was considered as an effective, economic and environmentally friendly method to synthesize these pyrazole derivatives.     

A facile method for the synthesis of nicotinonitriles from ketones via a one-pot chloromethyleneiminium salt mediated three-component reaction

Simple enolizable ketones such as acetophenones and benzalacetones were treated with malononitrile under Vilsmeier-Haack reaction conditions to afford 2-chloronicotinonitriles. The reaction proceeds via a one-pot chloromethyleneiminium salt mediated three-component reaction followed by sequential cyclization and aromatization under Vilsmeier-Haack reaction conditions.     

A concise and efficient way to synthesize polyenic diones directly from α,β-unsaturated methyl ketones

A concise and efficient approach to polyenic compounds containing important diketone structural fragments is developed from readily available α,β-unsaturated methyl ketones in the presence of copper(II) oxide, iodine, and dimethyl sulfoxide. This is a new carbon-carbon double bond-forming reaction from two methyl sp³ C-H bonds and an attractive route to introduce the SMe group into the molecule from inexpensive dimethyl sulfoxide. The hypothetic self-sorting tandem reaction mechanism is also proposed in this paper.     

Silylation-desilylation of propargyl amides: rapid synthesis of functionalised aldehydes and β-lactams

Propargyl functionalised β-silylalkenals were easily prepared starting from suitable propargyl compounds by a silylformylation process. In particular the use of propargyl tosyl amides allowed the synthesis of α,β-unsaturated aldehydes through a two-step sequence of silylformylation-desilylation reactions. TBAF was employed to induce the desilylation process that was performed under very mild experimental conditions and occurred along with an elimination step of the tosylamido moiety affording 2-methylaryl-2-alkenals with good yields and stereoselectivity. When the tosyl amides were reacted with a hydrosilane in the presence of catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) α-silylmethylene-β-lactams were synthesised through a silylcarbocyclisation process. A high chemoselectivity towards the β-lactam was observed when dialkyl propargyl amides were employed. The obtained β-lactams were easily transformed into the corresponding methylaryl-β-lactams by fluoride induced aryl migration-desilylation with total retention of configuration of the migrating group and complete stereoselectivity towards the more stable β-lactam (E)-isomer.     

Design and synthesis of novel spirocyclopropyl cyclohexane-1,3-diones and -1,3,5-triones for their incorporation into potent HPPD inhibitors

We report the design and the efficient synthesis of novel spirocyclopropyl cyclohexane-1,3-dione and -1,3,5-trione units to be incorporated into potent HPPD inhibitors. New routes involving original combinations of synthetic equivalents of α-cyclopropyl ketone-α-anion and α-cyclopropyl ester-β-cation are described.     

Zinc mediated reductive dimerization and cyclization of α,β-unsaturated ketones in the presence of a catalytic amount of mercury(II) chloride

The zinc mediated reductive dimerization and cyclization of α,β-unsaturated ketones gives functionalized cyclopentanols in good yield in the presence of a catalytic amount of mercury(II) chloride in N,N-dimethylformamide as solvent at room temperature. The reaction is regio- and stereo-selective producing 3,4-trans-diarylcyclopentanols selectively.     

A novel method for the synthesis of 3-fluoro-4-aryl-2-pyridone via unprecedented denitration

A simple and novel method to the synthesis of 3-fluoro-4-aryl-2-pyridone from a Michael-adduct of fluoronitroacetate and α,β-unsaturated ketone is reported. With (NH₄)₂CO₃ as the N-source and TsOH as the promoted acid, a series of fluorinated-pyridones was obtained with moderate to good yields.     

One Pot,Multi-component Synthesis of 3-[（4-Aryl-thiazol-2-yl）-hydrazono]-1,3-dihydro-indole-2-one

A series of 3-[（4-phenyl-thiazol-2-yl）-hydrazono]-1,3-dihydro-indole-2-one（4a-4g） and 3-{[4-（2-oxo2H-chromen-3-yl）-thiazol-2-yl]-hydrazono}-1,3-dihydro-indol-2-one（6a-6d） has been prepared in a one-step procedure from condensation reaction of isatin（1）,thiosemicarbazide（2） and bromoacetophenones（3）/or 3-（2-bromoacetyl）coumarins（4）.The method provides a simple and efficient route to prepare the compounds in good yields and in a short experimental time as compared to its stepwise procedure.     

An efficient preparation and some reactions of 2-dimethylaminomethylene-1,3-bis(dimethylimonio)propane diperchlorate

An alternative preparation of 2-dimethylaminomethylene-1,3-bis(dimethylimonio)propane diperchlorate from malonic acid is described along with its application to the synthesis of 2,4,6-trisubstituted phenols and 2-(N-(2,2-diformylethenyl)amino)pyridine.     

Convenient one-pot synthesis of functionalized （E）-2-arylvinyl bromides from （E）-4-（2-bromovinyl）phenyl acetate

A convenient one-pot synthesis of functionalized (E)-2-arylvinyl bromides was achieved by microwave-induced deacetylation and subsequent acylation using dicyclohexyl carbodiimide (DCC) and dimethylamino-pyridine (DMAP) at room temperature from (E)-4-(2-bromovinyl)phenyl acetate.     

Stereoselective synthesis of (Z)-γ-cyano-β-perfluoroalkyl-β,γ-unsaturated esters

(Z)-γ-Cyano-β-perfluoroalkyl-β,γ-unsaturated esters have been synthesized by the reaction of perfluoroacylated phosphonates with organozinc reagent in 50-71% (three steps) yields.     

A simpler and greener protocol for the preparation of β-acetylamino ketones by a one-pot reaction of aryl aldehydes, enolisable ketones, acetyl chloride and acetonitrile in the presence of zeolite Hβ as a reusable catalyst

β-Acetylamino ketones have been obtained in a one-pot coupling of an aldehyde with an enolisable ketone, acetyl chloride and acetonitrile in the presence of zeolite Hβ as catalyst at room temperature (26-28 °C). The procedure has the advantages of mild workup, circumvention of high temperature and inert atmosphere. The catalyst was found to be recyclable.