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 imidazo[4,5-<Emphasis Type="Italic">a</Emphasis>]acridones and imidazo[4,5-<Emphasis Type="Italic">a</Emphasis>]acridines as potential antibacterial agents

Abstract  New imidazo[4,5-a]acridone derivatives were synthesized from the rearrangement of 3H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. New imidazo[4,5-a]acridines were obtained from the reaction of imidazo[4,5-a]acridones in boiling POCl₃. All of these compounds exhibited antimicrobial activities comparable to streptomycin as reference drug. Graphical abstract        

Synthesis of (<Emphasis Type="Italic">E</Emphasis>)- and (<Emphasis Type="Italic">Z</Emphasis>)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles

Abstract  An efficient synthesis method for the preparation of a series of new (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles was developed. The reaction of (Z)- and (E)-3-styrylchromones with hydrazine hydrate afforded the corresponding (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles, except for nitro derivatives, where both (Z)- and (E)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles. The reaction mechanism for these transformations is discussed and the stereochemistries of all products were established by NMR experiments. Graphical abstract        

Synthesis and pharmacological activity of some synthesized polyazacyclopenta[<Emphasis Type="Italic">a</Emphasis>]naphthalenes and pyrazolo[3,4-<Emphasis Type="Italic">b</Emphasis>]pyridines using 2-amino-6-methyl-4-phenylnicotinonitrile as synthon

Abstract  A series of pyridines, pyrimidines, and their derivatives were synthesized using 2-amino-6-methyl-4-phenylnicotinonitrile as starting material. Thirteen new heterocyclics containing a pyridine ring were thus prepared. Pharmacological screening showed that many of these compounds have good anti-inflammatory and analgesic activity comparable with those of diclofenac potassium and valdecoxib as reference drugs. Assignment of the structures of the new compounds was based on chemical and spectroscopic evidence. Synthesis, spectroscopic data, and pharmacological properties of the compounds are reported in detail. Graphical Abstract        

A facile one-pot synthesis of 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-<Emphasis Type="Italic">d</Emphasis>]-1,2,4-triazolo[4,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidin-5-ones

Abstract  The reaction of 2-mercapto-6,7,8,9-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one or its 2-methylthio derivative with hydrazonoyl halides, in the presence of triethylamine, yielded 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones. The structure of the latter compounds was further confirmed by reaction of 2-mercapto-6,7,8,9-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one with the appropriate active chloromethylenes followed by coupling of the products with benzenediazonium chloride to afford the non-isolable azo-coupling products which converted, in situ, to 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones. The reaction mechanism was proposed and the products were screened for their biological activity. Some of the newly synthesized compounds had a moderate effect against some bacterial and fungal species. Graphical abstract        

DNA biosensors for the detection of aflatoxin producing <Emphasis Type="Italic">Aspergillus flavus</Emphasis> and <Emphasis Type="Italic">A. parasiticus</Emphasis>

Abstract  In this work, we report on the development of a DNA-based piezoelectric biosensor specific for the detection of an amplicon of the aflD gene of Aspergillus flavus and A. parasiticus. Expression of this gene is consistently correlated with a strain’s ability to produce aflatoxins that are considered very potent liver carcinogens in various animal species and humans. The DNA biosensor has been characterized with synthetic oligonucleotides and amplicons. Moreover, it has been applied to the analysis of real samples consisting of amplicons of DNA extracted from flours and feed contaminated with A. flavus and A. parasiticus. Graphical Abstract        

Convenient synthesis and NMR spectral studies of variously substituted <Emphasis Type="Italic">N</Emphasis>-methylpiperidin-4-one-<Emphasis Type="Italic">O</Emphasis>-benzyloximes

Abstract  A series of variously substituted N-methylpiperidin-4-one-O-benzyloximes were synthesized by three different methods. Among them, the direct conversion of 2,6-diarylpiperidin-4-ones into the corresponding oxime ethers (method A) was proved to be better than the other two methods in the sense of good yield, convenience, easy work-up and quick reaction time. All the synthesized compounds are characterized by IR, Mass and NMR (¹H NMR, ¹³C NMR, ¹H-¹H COSY, ¹H-¹³C COSY and HMBC) spectral studies. The conformational preference of the synthesized oxime ethers with/without alkyl and aryl substituents at C-3/C-5 and C-2/C-6 is discussed using the spectral data. The observed chemical shifts and coupling constants suggest that the synthesized oxime ethers adopt chair conformation with equatorial orientation of all the substituents, whereas 1-methyl-3-isopropyl-2,6-diphenylpiperidin-4-one-O-benzyloxime also exists in boat conformation. Based on the NMR data, the effects of oximination on ring carbons and their associated protons and alkyl substituents are discussed. In addition, the effect of NMe group on the 2,6-diarylpiperidin-4-one-O-benzyloximes was also studied. Graphical abstract        

Stability constants of some metal cation complexes of tetraphenyl <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">tert</Emphasis>-butylcalix[4]arene tetraketone in nitrobenzene saturated with water

Abstract  From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium taking place in the two-phase water–nitrobenzene system (M²⁺ = Ca²⁺, Ba²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺, UO₂ ²⁺, Mn²⁺, Co²⁺, Ni²⁺; 1 = tetraphenyl p-tert-butylcalix[4]arene tetraketone; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further, the stability constants of the 1 · M²⁺ complexes in water-saturated nitrobenzene were calculated; they were found to increase in the cation order Ba²⁺, Mn²⁺ < Co²⁺ < Cu²⁺, Ni²⁺ < Zn²⁺, Cd²⁺, UO₂ ²⁺ < Ca²⁺ < Pb²⁺. Graphical abstract        

Synthesis and antimicrobial evaluation of some 1,3-thiazole, 1,3,4-thiadiazole, 1,2,4-triazole,and 1,2,4-triazolo[3,4-<Emphasis Type="Italic">b</Emphasis>][1,3,4]-thiadiazine derivatives including a 5-(benzofuran-2-yl)-1-phenylpyrazole moiety

Abstract  Potassium hydrazinecarbodithioate were prepared by treatment of acid hydrazides with carbon disulfide in the presence of potassium hydroxide. Reaction of this potassium salt with hydrazine hydrate, phenacyl bromide, or hydrazonoyl chlorides afforded 1,2,4-triazole, 1,3-thiazole, and 1,3,4-thiadiazoles. Reaction of 1,2,4-triazole with phenacyl bromide or hydrazonoyl chlorides afforded the corresponding 1,2,4-triazolo[3,4-b][1, 3, 4]-thiadiazines. All these new compounds were screened for antibacterial and antifungal activity. Some had promising activity. Graphical abstract        

A one-pot multicomponent reaction for the synthesis of 2-amino-2-chromenes promoted by <Emphasis Type="Italic">N,N</Emphasis>-dimethylamino-functionalized basic ionic liquid catalysis under solvent-free condition

Abstract  A simple, clean, and environmentally benign three-component process to the synthesis of 2-amino-4H-chromenes using N,N-dimethylaminoethylbenzyldimethylammonium chloride, [PhCH₂Me₂N⁺CH₂CH₂NMe₂]Cl⁻, as an efficient catalyst under solvent-free condition is described. A wide range of aromatic aldehydes easily undergo condensations with α-naphthol and malononitrile under solvent-free condition to afford the desired products of good purity in excellent yields. Taking into account environmental and economical considerations, the protocol presented here has the merits of environmentally benign, simple operation, convenient work-up and good yields. Furthermore, the catalyst can be easily recovered and reused for at least five cycles without losing its activities. Graphical abstract        

Synthesis and serotonin antagonist and antianexity activities of pyrrolidine derivatives from 4-hydrazinyl-1-p-substituted phenyl-2,5-dihydro-1H-pyrrole-3-carbonitriles

Abstract   N-(p-substituted phenyl)-4-cyanopyrrolidin-3-ones and their corresponding hydrazines were prepared and used as starting materials to synthesize heterocyclic candidates as serotonin antagonist and antianexity agents. Condensation of hydrazines with selected aromatic aldehydes afforded the corresponding Schiff bases. The hydrazines were treated with phenyl isothiocyanate to afford the corresponding thiosemicarbazides, which were cyclized with ethyl bromoacetate to N-phenylthiazolidinones. The hydrazine was reacted with 1,2,4,5-tetrachlorophthalic anhydride to give the tetrachloroimide derivative. It was reacted with benzoyl acetonitrile, 2-(bismethylsulfanyl-methylene)malononitrile, 2-ethoxymethylenemalononitrile, or 2-cyano-3-ethoxyacrylic acid ethyl ester to afford the corresponding pyrazoline derivatives. Schiff bases were obtained by simple condensation of the hydrazine with different carbonyl compounds. All the compounds were screened for their serotonin antagonistic and antianexity activities, and they showed high activities compared to buspirone and diazepam as controls. Graphical abstract        

Novel syntheses of some new 3,4-dihydrospiro{benzimidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyridine-3,3′-indolin}-2′-one derivatives

Abstract  2-Methylbenzimidazole 1 reacted with 3-dicyanomethylidine-1-ethyl-2-oxoindoline 2 in ethyl acetate to afford 1-amino-2-cyano-3,4-dihydro-1′-ethylspiro{benzimidazo[1,2-a]pyridine-3,3′-indolin}-2′-one 6, which was used as a key intermediate in the synthesis of fused spiropolyheterocyclic derivatives of benzimidazopyridopyrimidine and/or benzimidazonaphthyridine nucleus incorporating an indoline moiety. Graphical abstract        

Spectral,magnetic, thermal,antimicrobial, and eukaryotic DNA studies on acetone [<Emphasis Type="Italic">N</Emphasis>-(3-hydroxy-2-naphthoyl)]hydrazone complexes

Abstract  Acetone [N-(3-hydroxy-2-naphthoyl)] hydrazone (H₂AHNH) has been prepared and its structure confirmed by elemental analysis and ¹H NMR spectroscopy. It has been used to produce diverse complexes with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and U(VI)O₂ ions. The complexes obtained have been investigated by thermal analysis, spectral studies (¹H NMR, IR, UV–visible, ESR), and magnetic measurements. IR spectra suggest that H₂AHNH acts as a bidentate ligand. The electronic spectra of the complexes and their magnetic moments provide information about geometries. The ESR spectra give evidence for the proposed structure and the bonding for some Cu(II) complexes. Thermal decomposition of the Ni(II) and Cu(II) complexes afforded metal oxides as final products. Kinetic data were obtained for each stage of thermal degradation of some of the complexes using the Coats–Redfern method. The formation of complexes in solution was studied pH-metrically and the order of their stability constants (log K) was found to be U(VI)O₂ > Cu(II) > Zn(II) > Ni(II) > Cd(II) > Co(II). Antimicrobial and eukaryotic DNA studies were carried out. Graphical abstract        

Synthesis of benzohetero[3, 2-<Emphasis Type="Italic">a</Emphasis>]pyrimidines using cyclic β-keto lactone as a building block

Abstract  A novel method for the synthesis of 3-(2-substituted ethyl)-2-methylbenzohetero[3,2-a]pyrimidines in high yield (80–85%) was achieved, which involves a dihydrofuranone intermediate, readily obtained from β-ketolactone to 2-aminobenzoheterocycles. The major advantage of the methodology is the high yield and product purity. 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        

Identification of new<Emphasis Type="Italic"> O</Emphasis>-GlcNAc modified proteins using a click-chemistry-based tagging

The O-linked β-N-acetylglucosamine (O-GlcNAc) modification is an abundant post-translational modification in eukaryotic cells. This dynamic glycosylation plays a fundamental role in the activity of many nuclear and cytoplasmic proteins and is associated with pathologies like type II diabetes, Alzheimer’s disease or some cancers. However the exact link between O-GlcNAc-modified proteins and their function in cells is largely undefined for most cases. Here we report a strategy based on the 1,3-dipolar cycloaddition, called click chemistry, between unnatural N-acetylglucosamine (GlcNAc) analogues (substituted with an azido or alkyne group) and the corresponding biotinylated probe to specifically detect, enrich and identify O-GlcNAc-modified proteins. This bio-orthogonal conjugation confirms that only azido analogue of GlcNAc is metabolized by the cell. Thanks to the biotin probe, affinity purification on streptavidin beads allowed us to identify 32 O-GlcNAc-azido-tagged proteins by LC-MS/MS analysis in an MCF-7 cellular model, 14 of which were previously unreported. This work illustrates the use of the click-chemistry-based strategy combined with a proteomic approach to get further insight into the pattern of O-GlcNAc-modified proteins and the biological significance of this post-translational modification. Figure Detection of biotinylated O-GlcNAz proteins in MCF-7 cells Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Caroline Gurcel and Anne-Sophie Vercoutter-Edouart contributed equally to this work.     

<Superscript>13</Superscript>C-labeled bilirubin: synthesis of 3<Superscript>1</Superscript>(3<Superscript>2</Superscript>),17<Superscript>1</Superscript>(17<Superscript>2</Superscript>)-di-[<Superscript>13</Superscript>C]-mesobilirubin-XIIIα

Abstract  The title compound, labeled with ¹³C in the ethyl groups was synthesized from K¹³CN and low-molecular-weight components. The synthetic relay compound was 3¹(3²)[¹³C]-xanthobilirubinic acid methyl ester in a synthetic route that leads to a label in the ethyl β-substituent of a dipyrrinone model for bilirubin. This labeled dipyrrinone was oxidatively coupled to the dimethyl ester of mesobiliverdin-XIIIα, thereby providing a route to a ¹³C-labeled mesobiliverdin and mesobilirubin, with one carbon of each ethyl being 98% ¹³C-enriched. Graphical Abstract        

Fluorescent probe for Zn<Superscript>2+</Superscript> with light-harvesting pyrenyl groups: sensitization via intramolecular energy transfer

Abstract  Bis[N-(1-pyrenylmethyl)salicylideneaminato]zinc(II) emits intense fluorescence on excitation of the pyrenyl group. This fluorescence originates from the excited state of the salicylideneamine moiety, indicating that efficient intramolecular energy transfer takes place. The occurrence of such efficient energy transfer is accounted for by significant spectral overlap between the emission from the S₁ state of the pyrenyl group and the absorption of the salicylideneamine–zinc complex. 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        

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