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        

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 extraction and DFT study on the complexation of K+ with valinomycin

Abstract  From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constant of protonated tetraethyl p-tert-butylcalix[4]arene tetraacetate in nitrobenzene saturated with water was determined. By using DFT calculations, the most probable structure of the tetraethyl p-tert-butylcalix[4]arene tetraacetate·H₃O⁺ complex species was derived. Graphical Abstract        

On the protonation of dibenzo-18-crown-6

Abstract  The stability constant of the dibenzo-18-crown-6·H₃O⁺ cationic complex species dissolved in nitrobenzene saturated with water has been determined from extraction experiments in the two-phase water–nitrobenzene system and from γ-activity measurements. Various structures of protonated dibenzo-18-crown-6 are discussed. Graphical abstract        

C-Furyl glycosides, II: synthesis and antimicrobial evaluation of C-furyl glycosides bearing pyrazolines, isoxazolines, and 5,6-dihydropyrimidine-2(1H)-thiones

Abstract  New C-furyl glycosides bearing pyrazolines, isoxazolines, and dihydropyrimidine-2(1H)-thiones were synthesized in order to increase the number of tested compounds screened for antimicrobial activity. The antimicrobial activity screening showed that the pyrazoline derivatives were the most active compounds. Graphical abstract        

A mild and expedient one-pot synthesis of substituted benzimidazoles in water using a phase-transfer catalyst

Abstract  1-Alkyl/phenyl-2-arylbenzimidazoles have been synthesized in very good to excellent yields by a one-pot condensation of N-alkyl/phenyl-o-phenylenediamines with aryl aldehydes in water at room temperature using cetylpyridinium bromide as a cheap and eco-friendly catalyst. Graphical abstract        

An efficient and convenient protocol for the synthesis of novel 1′H-spiro[isoindoline-1,2′-quinazoline]-3,4′(3′H)-dione derivatives

Abstract  An efficient and direct procedure for the synthesis of novel spiro[isoindoline-1,2′-quinazoline]-3,4′(3′H)-dione derivatives is described. The process employs a condensation reaction of 2-aminobenzamides and isatins in the presence of a catalytic amount of KAl(SO₄)₂.12H₂O (alum) in ethanol under reflux. Graphical Abstract        

The 3D porous metal-organic framework constructed by Cd(II) with 2-methylimidazole-4,5-dicarboxylic acid

Abstract  A 3D metal-organic framework, [C₆H₃CdN₂O₄]·NH₄, was synthesized solvothermally and structurally characterized by single-crystal X-ray structure determination. This compound crystallizes in the tetragonal system with the space group P42/nmc. The crystal structure presents a 3D framework and open channels, exhibiting guest-coordination sites at channel walls and strong fluorescent emission. Graphical abstract        

Synthesis of imatinib: a convergent approach revisited

Abstract  A classical convergent approach for the synthesis of the anticancer drug imatinib has been substantially improved. Imatinib was assembled by coupling the amine and carboxylic acid precursors by using N,N′-carbonyldiimidazole (CDI) as a condensing agent. Both intermediates have been synthesized by novel efficient methods. 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        

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        

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        

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        

Dinuclear Fe(III) complexes with spin crossover

Abstract  A series of dinuclear Fe(III) complexes was synthesized in which the Schiff-base blocking ligand L⁵ coordinates each of the centers which are linked by a bidentate, bipyridine-type ligand. For these systems, [L⁵Fe^III{bridge}Fe^IIIL⁵](BPh₄)₂, thermally induced spin crossover is observed. The corollary of the systems is that the spin crossover interferes with the magnetic exchange interaction. The overlap of the energy bands of the LL and HH reference states (L, low-spin; H, high-spin) causes the exchange interaction to act against the spin crossover (leading to incompleteness or gradual behavior). Graphical abstract        

SARs of the antiprotozoal action of 6,7-diaryl-bicyclo[2.2.2]octan-2-ols

Abstract  Several 4-amino-6,7-diarylbicyclo[2.2.2]octan-2-ols bearing varying substituents on the aromatic rings were synthesized following a manual method for applying the Hansch approach. All new compounds were tested for their activity against the causative organisms of East African sleeping sickness and malaria tropica. Structure activity relationships are discussed. Graphical abstract        

Ferric nitrate in the presence of catalytic amounts of KBr or NaBr: an efficient and homoselective catalytic media for the selective oxidation of sulfides to sulfoxides

Abstract  A mild, efficient, and highly selective oxidation method of sulfides to sulfoxides using Fe(NO₃)₃·9H₂O and catalytic amounts of KBr or NaBr in the presence of wet SiO₂ (50% w/w) has been developed. A variety of aliphatic and aromatic sulfides were selectively oxidized at room temperature in good to excellent yields. Graphical abstract        

One-step regioselective green synthesis of 2,3-mannoepoxy-β-cyclodextrin under aqueous conditions

Abstract  A simple method for the straightforward regioselective synthesis of 2,3-mannoepoxy-β-cyclodextrin, which is a valuable precursor for further functionalization of β-cyclodextrin, is achieved under aqueous conditions without any organic solvents at a moderate yield. Graphical abstract        

Inhibition of J-aggregation of <Emphasis Type="Italic">meso</Emphasis>-tetra(4-sulfonatophenyl)porphyrin by an ionic liquid with π-conjugated character

Abstract  UV–visible spectral observations indicate that the J-aggregation of protonated meso-tetra(4-sulfonatophenyl)porphyrin ([H₂TSPP]²⁺) under acidic conditions is completely inhibited by the π–π counteraction between 1-butyl-pyridinium tetrafluoroborate ([bpy]BF₄) and [H₂TSPP]²⁺. The studies also suggest that the intermolecular π–π force is of relative importance for the J-aggregates of [H₂TSPP]²⁺ and the intermolecular electrostatic force for the H-aggregates. 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        

(<Emphasis Type="Italic">S</Emphasis>)-(−)-α-Methylbenzylamine as chiral auxiliary in the synthesis of (+)-lortalamine

Abstract  (+)-Lortalamine was synthesised using (S)-(−)-α-methylbenzylamine as a chiral auxiliary. The stereochemistry of an intermediate compound was established on the basis of X-ray crystallography, allowing unambiguous assignment of the absolute configuration. Graphical abstract