Polymer-supported zinc chloride: a highly active and reusable heterogeneous catalyst for one-pot synthesis of 2,4,5-trisubstituted imidazoles

Abstract  A polymer-supported Lewis acid catalyst was prepared and found to be extremely efficient for the preparation of imidazole derivatives via three-component condensation of benzil, aldehydes, and ammonium acetate under mild conditions. The catalyst is stable and can be easily recovered and reused at least four times without any loss of activity. Graphical Abstract        

Thermal isomerization in cyclopenta[<Emphasis Type="Italic">fg</Emphasis>]aceanthrylene

Abstract  Two mechanisms for the isomerization of cyclopenta[fg]aceanthrylene to acefluoranthene were revealed. The first pathway occurs via a cyclobutyl intermediate, whereas the second pathway involves a transition state that contains an sp ³-hybridized carbon atom. Both patterns show that the Stone-Wales rearrangement requires extremely high activation energy and indicate that the isomerization process can occur only under a drastic temperature regime. Graphical abstract        

Chemistry of chromium bis-acetylide complexes

Abstract  Stable paramagnetic Cr(II) and Cr(III) bis(alkynyl) complexes of the type [trans(RC≡C)₂Cr(dmpe)₂] ⁿ⁺ (R = Ph, SiMe₃, SiEt₃, C≡C–SiMe₃ n = 0, 1) were prepared and characterised by NMR, cyclic voltammetry, EPR, magnetic measurements, and X-ray single-crystal diffraction studies. Graphical Abstract        

A chemoselective and one-pot synthesis of 5-hydroxy and 7-hydroxy coumarin derivatives

Abstract  An efficient one-pot reaction of dialkyl acetylenedicarboxylates with 2,4-dihydroxybenzo(or aceto)phenones in the presence of triphenylphosphine produces 5-hydroxy- and 7-hydroxycoumarin derivatives. The novel procedure features short reaction time, fairly good yields, and simple workup. Graphical abstract        

A chemoenzymatic synthesis of 3,4,5,6-tetrahydro-2H-benzo[b][1,4]-oxazocine-3,5-dione and its derivatives

Abstract  The enzymatic cyclization of phenoxyacetylcyanomethylenetriphenylphosphorane derivatives using pre-treated baker’s yeast cells, a rapid one-pot assembly of heteromacrocyclic compounds, is described. Graphical abstract        

Three-components condensation catalyzed by molecular iodine for the synthesis of 2,4,6-triarylpyridines and 5-unsubstituted-3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions

Abstract  One-pot, three-components synthesis of 2,4,6-triarylpyridines and 5-unsubstituted-3,4-dihydropyrimidin-2(1H)-ones was performed under solvent-free conditions using molecular iodine as the catalyst in moderate to good product yields. Graphical abstract        

Enantioselective synthesis of 1-arylethanediols by rhodium-catalyzed transfer hydrogenation of α-tosyloxyarylketones

Abstract  Catalytic transfer hydrogenation of α-tosyloxyarylketones mediated by a chiral rhodium complex using an azeotropic mixture of formic acid/triethylamine afforded the corresponding 1-arylethanediol monotosylates in excellent yield with high enantioselectivity. Graphical abstract        

Preparation of amidoalkyl naphthols by a three-component reaction catalyzed by 2,4,6-trichloro-1,3,5-triazine under solvent-free conditions

Abstract  An efficient one-pot synthesis of amidoalkyl naphthols is described. This involves the three-component reaction of 2-naphthol, aromatic aldehydes and amide or urea in the presence of a catalytic amount of 2,4,6-trichloro-1,3,5-triazine (TCT, cyanuric chloride) under solvent-free conditions. Graphical abstract        

Facile synthesis of highly functionalized stable ketenimines by a three-component reaction of alkyl isocyanides, dialkyl acetylenedicarboxylates and ethyl carbazones

Abstract  The reactive intermediate generated by the reaction of alkyl isocyanides and dialkyl acetylenedicarboxylates was trapped by ethyl carbazones to produce stable ketenimine derivatives in good yield. The reaction is characterized by mild conditions, high selectivity, and tolerance to various functional groups. Graphical abstract        

A one-pot synthesis of functionalized ethyl 1,3-thiazole-5-carboxylates from thioamides or thioureas and 2-chloro-1,3-dicarbonyl compounds in an ionic liquid

Abstract  A simple one-pot synthesis of functionalized ethyl 1,3-thiazole-5-carboxylates from the reaction of 2-chloro-1,3-dicarbonyl compounds with thioureas or thioamides in the presence of 1-butyl-3-methylimidazolium trifluoromethanesulfonate is described. Graphical abstract        

A synthesis of diethyl alkylsulfanylmethylmalonates catalyzed by KOH in an ionic liquid

Abstract  1-Ethyl-3-methylimidazolium bromide was used as a green recyclable alternative to volatile organic solvents for KOH catalyzed three-component synthesis of diethyl alkylsulfanylmethylmalonates from aldehydes, diethyl malonate, and alkylthiols. Graphical Abstract  A synthesis of diethyl alkylsulfanylmethylmalonates catalyzed by KOH in an ionic liquid      

Chemoselective trimethylsilylation of alcohols catalyzed by saccharin sulfonic acid

Abstract  Saccharin sulfonic acid was easily prepared by the reaction of saccharin with neat chlorosulfonic acid at room temperature. This reagent is efficiently able to catalyze the chemoselective trimethylsilylation of alcohols with hexamethyldisilazane in the presence of amines and thiols. Graphical abstract        

Synthesis of sulfides under solvent- and catalyst-free conditions

Abstract  A simple, highly efficient, and green protocol has been developed for preparation of sulfides from alkyl or aryl thiols and benzyl-, allyl-, t-butyl, and adamantyl halides under solvent- and catalyst-free conditions. Graphical abstract        

Efficient conversion of aldoximes to nitriles using phosphoric acid diethyl ester 2-phenylbenzimidazol-1-yl ester

Abstract  Aromatic aldoximes were converted to the corresponding nitriles in good to excellent yields by employing phosphoric acid diethyl ester 2-phenylbenzimidazol-1-yl ester as reagent. The method was equally effective for oximes bearing electron-donating and electron-withdrawing substituents. Graphical Abstract        

Amino acid derivatives, X [1]: synthesis and antimicrobial evaluation of α-amino acid esters bearing a N1-protected tryptophan side chain

Abstract  A series of peptide derivatives conjugated with N¹-protected tryptophan residue was synthesized. The prepared compounds were tested for antimicrobial activity against four different bacterial species displaying different degrees of antibacterial activities or inhibitory actions. Graphical Abstract        

An efficient 1,3-allylic carbonyl transposition of chalcones

Abstract  A very simple, convenient, and efficient procedure is reported for the 1,3-allylic carbonyl transposition of chalcones. The transposition can be achieved by reduction of chalcones to 1,3-diarylpropan-1-ols and dehydration of the latter to give 1,3-diarylpropenes followed by benzylic/allylic oxidation. Graphical abstract        

N-Methylimidazole-promoted efficient synthesis of 1,3-oxazine-4-thiones under solvent-free conditions

Abstract  A novel method for oxazine ring formation is established using the reaction of ammonium thiocyanate and acid chlorides with napthols in the presence of N-methylimidazole to afford [1,3]oxazine-4-thione derivatives in excellent yields. Graphical abstract        

Polyvinylpolypyrrolidone-supported boron trifluoride: a high-loaded,polymer-supported Lewis acid for the Ritter reaction

Abstract  A Mild and efficient method for preparing amides by reaction of nitriles with benzhydrol and tertiary alcohols is described using polyvinylpolypyrrolidone-supported boron trifluoride. Selective amidation of benzhydrol in the presence of primary benzyl alcohols was also achieved. Graphical abstract        

Practical and general method for the direct synthesis of alkyl fluorides from alcohols under mild conditions: a reinvestigation

Abstract  In contrast to the results presented in a previous report, the direct conversion of alcohols to alkyl fluorides with triphenylphosphine and potassium fluoride in CCl₄/DMF under mild conditions failed. Graphical Abstract        

A combined experimental and theoretical study on the complexation of Li<Superscript>+</Superscript> with valinomycin

Abstract  From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constant of the valinomycin–lithium complex in nitrobenzene saturated with water was determined. Further, the structure of the resulting complex was indicated by means of the density functional level of theory (DFT) calculations. Graphical abstract