N-Trifluoroethoxy Benzotriazolium Triflate: A Readily Available Reagent for Direct Radical Trifluoroethoxylation of Alkenes

Herein, we describe the development and application of a novel benzotriazole-based reagent toward radical trifluoroethoxylation. Various alkene classes, including styrene derivatives, enol carbonates, and allyl silanes, are viable reaction partners in this transformation, yielding diverse trifluoroethoxylated products. Furthermore, this method is readily applicable for the late-stage modification of natural product and drugs molecules. Mechanistic and computational studies suggest the intermediacy of an OCH2CF3 radical generated under photocatalytic conditions.

DMF-DMA catalyzed Synthesis, molecular docking, in-vitro, in-silico design, and binding free energy studies of novel thiohydantoin derivatives as antioxidant and antiproliferative agents targeting EGFR tyrosine kinase and aromatase cytochrome P450 enzyme

A set of novels 2-thiohydantoin derivatives were synthesized and enaminone function was discussed at position 5 using DMFDMA catalyst which result in formation of pyrazole, isoxazole, benzoxazepine by using reagents such as hydrazine, hydroxylamine and 2-aminothiophenol. These newly synthesized compounds were evaluated for their antioxidant and antiproliferative activity. In vitro studies on the effect of 2-thiohydantoin on scavenging 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) confirmed the free radical scavenging and antioxidant activity of 2-thiohydantoin. The synthesized compounds show significant antioxidant activity. The in vitro antitumor activity of 2-thiohydantoin on MCF7 (breast) and PC3 cells (prostate) was evaluated using MTT assay. Some of the synthesized compounds show significant to moderate antiproliferative properties compared to reference drug erlotinib. Among all, compound 4a exhibit potent antitumor properties against MCF7 and PC3 cancer cell lines with IC50 = 2.53 ± 0.09 /ml & with IC50 = 3.25 ± 0.12 µg/ml respectively and has potent antioxidant activity with IC50 = 10.04 ± 0.49 µg/ml.

Advances in the synthesis and applications of macrocyclic polyamines

Macrocyclic polyamines constitute a significant class of macrocyclic compounds that play a pivotal role in the realm of supramolecular chemistry. They find extensive applications across diverse domains including industrial and agricultural production, clinical diagnostics, environmental protection and other multidisciplinary fields. Macrocyclic polyamines possess a distinctive cavity structure with varying sizes, depths, electron-richness degrees and flexibilities. This unique feature enables them to form specific supramolecular structures through complexation with diverse objects, thereby attracting considerable attention from chemists, biologists and materials scientists alike. However, there is currently a lack of comprehensive summaries on the synthesis methods for macrocyclic polyamines. In this review article, we provide an in-depth introduction to the synthesis of macrocyclic polyamines while analysing their respective advantages and disadvantages. Furthermore, we also present an overview of the recent 5-year advancements in using macrocyclic polyamines as non-viral gene vectors, fluorescent probes, diagnostic and therapeutic reagents as well as catalysts. Looking ahead to future research directions on the synthesis and application of macrocyclic polyamines across various fields will hopefully inspire new ideas for their synthesis and use.

Total Synthesis of the 2,5-Disubstituted γ-Pyrone E1 UAE Inhibitor Himeic Acid A

The first total synthesis of the E1 ubiquitin-activating enzyme inhibitor, himeic acid A, is reported. A McCombie reaction was used to form the core γ-pyrone via a 6π-electrocyclization. A dioxenone ring-opening/acyl ketene trapping reaction with a primary amide provided the unusual unsymmetrical imide functionality. Other key steps include the use of an Evans auxiliary alkylation (d.r. ≥ 95:5) to install the (S)-2-methyl succinic acid fragment and a cross-metathesis to install the unsaturated side-chain.

Ecofriendly Synthesis of Formamidine Derivatives Catalyzed by Al-MCM- 41 Mesoporous Materials

Abstract:

Formamidine derivatives have been synthesized in excellent yields at room temperature from primary amine and N,N-dimethylformamide dimethylacetal (DMF-DMA) in the presence of a catalytic amount of Al-MCM-41 synthesized from natural bentonite as silica and aluminum source. The advantages of this method are the use of a cheap, stable, non-toxic, and readily available catalyst, easy work-up, improved yields, and solvent-free conditions.

Catalytic Direct Cyanomethylenation of C(sp3)-H Bonds via a One-Step Double C-C Bond Formation

An elegant and catalytic procedure for the one-step cyanomethylenation of C(sp³)-H bonds adjacent to benzazoles and ketones is described herein using DMF as a C-1 unit and TMSCN as the cyanide source. The copper-mediated reaction between DMF and TMSCN gives a cyanomethylene radical intermediate that reacts with 2-alkylbenzazoles or alkylketones to furnish desired cyanomethylenated compounds under palladium catalysis. Subsequent interconversion of cyanomethylenated products makes the protocol synthetically attractive.

C4-aldehyde of guaiazulene: synthesis and derivatisation

Guaiazulene is an alkyl-substituted azulene available from natural sources and is a much lower cost starting material for the synthesis of azulene derivatives than azulene itself. Here we report an approach for the selective functionalisation of guaiazulene which takes advantage of the acidity of the protons on the guaiazulene C4 methyl group. The aldehyde produced by this approach constitutes a building block for the construction of azulenes substituted on the seven-membered ring. Derivatives of this aldehyde synthesised by alkenylation, reduction and condensation are reported, and the halochromic properties of a subset of these derivatives have been studied.

Synthesis of indole-tethered [1,3,4]thiadiazolo and [1,3,4]oxadiazolo[3,2-a]pyrimidin-5-one hybrids as anti-pancreatic cancer agents

New indole-tethered [1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one (8a-j) and [1,3,4]oxadiazolo[3,2-a]pyrimidin-5-one hybrids (9a-e) were synthesized using [4+2] cycloaddition reactions of functionalized 1,3-diazabuta-1,3-dienes with indole-ketenes. All molecular hybrids were structurally characterized by spectroscopic techniques (IR, NMR, and HRMS) and screened for their anti-pancreatic cancer activity in vitro. The [1,3,4]oxadiazolo[3,2-a]pyrimidin-5-one hybrids (9a-e) showed stronger anti-pancreatic cancer activity than the [1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one hybrids (8a-j) against the PANC-1 cell line. Compound 9d bearing an ortho-chlorophenyl moiety emerged as the most potent anti-pancreatic cancer agent with an IC₅₀ value of 7.7 ± 0.4 µM, much superior to the standard drug Gemcitabine (IC₅₀ > 500 µM). The discovery of these [1,3,4]thiadiazolo and [1,3,4]oxadiazolo[3,2-a]pyrimidin-5-one hybrids elicits their potentials as pursuable candidates for pancreatic cancer chemotherapy.

Structural investigation of perfluorocarboxylic acid derivatives formed in the reaction with N,N-dimethylformamide dialkylacetals

A structural investigation of perfluorocarboxylic acid derivatives formed in the reaction with N,N-dimethylformamide dialkylacetals employing several techniques of mass spectrometry (MS) is described. Two derivatizing reagents, dimethylformamide dimethyl acetal (DMF-DMA) and dimethylformamide diethylacetal (DMF-DEA) were used. In contrast to carboxylic acids, perfluorocarboxylic acids are not able to form alkyl esters as the main product in this reaction. We found that perfluorooctanoic acid (PFOA) forms a salt with N,N-dimethylformamide dialkylacetals. This salt undergoes a further reaction inside the injection block of a gas chromatograph (GC) by loss of CO₂ and then forms 1,1-perfluorooctane-(N,N,N,N-tetramethyl)-diamine. The GC-MS experiments using both electron ionization (EI) and positive-ion chemical ionization (PCI) revealed that the same reaction products are formed with either derivatizing reagent. Subjecting the perfluorocarboxylic acid derivative to electrospray ionization (ESI) and direct analysis in real time (DART), both positive- and negative-ion modes indicated that cluster ions are formed. In the positive-ion mode, this cluster ion consists of two iminium cations and one PFOA anion, while in the negative-ion mode, it comprises two PFOA anions and one cation. The salt structure was further confirmed by liquid injection field desorption/ionization (LIFDI) as well as infrared (IR) spectroscopy. We propose a simple mechanism of N,N,N',N'-tetramethylformamidinium cation formation. The structure elucidation is supported by specific fragment ions as obtained by GC-EI-MS and GC-PCI-MS analyses.

Solvent-Free Synthesis of 2,5Bis((dimethylamino)methylene)cyclopentanone

Available protocols for the synthesis of ketocyanine dyes precursor 2,5-bis((dimethylamino)methylene)cyclopentanone are not straightforward and the reported yields are low to moderate. The important feature in the synthesis of this product through organocatalyzed condensation of cyclopentanone and N,N-Dimethylformamide dimethyl acetal is the removal of methanol produced during the reaction. By studying the reaction profile, in particular the selectivity for the formation of mono- and bis-condensation products, a high yield of the desired product can be obtained through an operationally simple and solvent-free protocol.

Design, Synthesis, and Biological Evaluation of Triazolyl- and Triazinyl-Quinazolinediones as Potential Antitumor Agents

Novel 6(3-1H-1,2,4-triazol-1-yl)-3-phenylquinazoline-2,4(1H,3H)-diones (7a–e) were synthesized from different enaminones (6a–e) with 6-hydrazinyl-3-phenylquinazoline-2,4(1H,3H)-dione. 2,6(4-2-Substituted-1,3,5-triazin-1(2H)-yl)-3-phenylquinazoline-2,4(1H,3H)-diones (8a–k) were synthesized from the reaction of 1-(2,4-dioxo-3-phenyl-1,2,3,4-tetrahydroquinazolin-6-yl)thiourea, urea, or guanidine (3a–c) with enaminones (6a–e), and a series from 3-substituted-2-imino-1,3,5-triazin-1(2H)-yl-sulfonyl-phenyl-1-methylquinazoline-2,4(1H,3H)-dione (12a–j) were obtained from the reaction of N-(diaminomethylene)-4-(1-methyl-2,4-dioxo-1,2-dihydroquinazolin-3(4H)-yl)benzenesulfonamide (11) with the enaminone (6a–j). The antitumor activity of the synthesized compounds was evaluated against two human cell lines: human colon carcinoma HCT116 and human hepatocellular carcinoma HEP-G2. Some of the tested compounds showed significant potency compared to the reference drug staurosporin.

New polysubstituted monoterpenic thiazolidinones: synthesis, spectroscopic and crystal structure studies

The synthesis of three new polysubstituted monoterpenic thiazolidin-4-ones, namely (Z)-3-methyl-2-{(E)-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene]hydrazinylidene}thiazolidin-4-one, C14H21N3OS (2), (2Z,5Z)-5-[(dimethylamino)methylidene]-2-{(E)-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene]hydrazinylidene}thiazolidin-4-one, C16H24N4OS (3), and (2Z,5Z)-5-[(dimethylamino)methylidene]-3-methyl-2-{(E)-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene]hydrazinylidene}thiazolidin-4-one, C17H26N4OS (4), is reported, starting from the corresponding thiosemicarbazones obtained from naturally occurring (R)-camphor. All the newly obtained thiazolidin-4-ones have been fully characterized by HRMS and 1H and 13C (1D and 2D) NMR spectroscopy. Two of them, i.e. 2 and 3, were identified by single-crystal X-ray crystallography, confirming the synthetic pathway and the spectroscopic analyses. In 3, there are two roughly identical molecules within the asymmetric unit with the same absolute configuration. These two molecules are linked through N—H...O hydrogen bonds, building an R 2 2(8) graph-set motif.

DMFDMA catalyzed synthesis of 2-((Dimethylamino)methylene)-3,4-dihydro-9-arylacridin-1(2H)-ones and their derivatives: in-vitro antifungal, antibacterial and antioxidant evaluations

A series of 3,4-dihydro-9-arylacridin-1(2H)-ones was synthesized and enaminone function was introduced at the C-2 position using DMFDMA catalyst which in turn successfully converted into pyrazole, isoxazol, 1-phenyl-1H-pyrazole by treating it with reagents such as hydrazine, hydroxylamine and phenylhydrazine. These newly synthesized compounds were evaluated for their antibacterial activity against a series of Gram-Positive bacteria including Staphylococcusaureus, Bacilluscereus, StaphylococcusaureusMLS16 and Gram-Negative bacteria including Klebsiellaplanticol, Escherichiacoliand Pseudomonasaeruginosaand also against fungal strains including Candidaalbicans, Candidaparapsilosis, Candidaglabrata, Candidaaaseri, Aspergillusnigerand Issatchenkiahanoiensis. The compounds3aand6aexhibited considerable antifungal activity (MIC value 0.007 and 0.006 μM) against Candidaalbicansand Aspergillusnigerrespectively. The compound4ashowed excellent antibacterial activity towards EscherichiaColi(MIC = 0.003 μM) and the compound5afound to show prominent DPPH radical scavenging activity with EC50value 16.85±1.5μg mL−1.

Ag(I)-Catalyzed [3 + 2]-Annulation of Cyclopropenones and Formamides via C-C Bond Cleavage

An unprecedented Ag-catalyzed [3 + 2]-annulation of cyclopropenones and DMF via C-C bond cleavage is disclosed. This protocol exhibited excellent chemo- and regio-selectivity, and tolerated various functional groups. More importantly, DMF served as the C═O bond in the cycloaddition reaction, providing an efficient way to construct γ-aminobutenolides. In addition, transesterification reaction occurred when DMF was replaced by esters.

Photophysical and Photochemical Properties of 3-methylpterin as a New and More Stable Pterin-type Photosensitizer

Pterin derivatives are heterocyclic compounds which are present in different biological systems. Neutral aqueous solutions of pterins present acid-base and keto-enol equilibria. These compounds, under UV-A radiation fluoresce, undergo photooxidation, generate reactive oxygen species and photoinduce the oxidation of biological substrates. As photosensitizers, they may act through different mechanisms, mainly through an electron transfer-initiated process (type-I mechanism), but they also produce singlet molecular oxygen (¹ O₂ ) upon irradiation (type-II mechanism). In general, upon UV-A excitation two triplet states, corresponding to the lactim and lactam tautomers, are formed, but only the last one is the responsible for the photosensitized reactions of biomolecules. We present a study of the photochemical properties of 3-methylpterin (3-Mep) which, in contrast to most pterin derivatives, exists only in the lactam form. Also an improvement in the synthesis of 3-Mep is reported. The spectroscopic properties 3-Mep in aqueous solution were similar to those of the unsubstituted pterin derivative (Ptr) in its acid form, such as absorption, fluorescent and phosphorescent emission spectra. Experiments using 2'-deoxyguanosine 5'-monophosphate (dGMP) as oxidizable target demonstrated that methylation at C-3 position of the pterin moiety does not affect significantly the efficiency of photosensitization, but results in a more photostable sensitizer.

Antimicrobial activity of thiophene derivatives derived from ethyl (E)-5-(3-(dimethylamino)acryloyl)-4-methyl-2-(phenylamino)thiophene-3-carboxylate

Background

The thiophene nucleus has been recognized as an important entity in the synthesis of heterocyclic compounds with promising pharmacological characteristics.

Results

A number of new heterocyclic compounds incorporating thiophene species have been prepared from the titled enaminone via the reaction with different nucleophiles and electrophiles. The structure elucidation of the designed compounds was derived from their spectral information. The results of antimicrobial activity of the prepared compounds revealed that derivatives 7b and 8 exhibited activity comparable to the standard drugs ampicillin and gentamicin for all tested bacteria species. Additionally, compound 3 displayed potent activity against Aspergillus fumigates, whereas compounds 5, 6, and 7a showed good activity against Syncephalastrum racemosum.

Conclusions

We have synthesized a number of new thiophene-containing compounds. The results of antimicrobial activity of the prepared compounds revealed that changing the substituents at position-2 of thiophene ring significantly affect their biological activity. The pyridine side chain derivatives in compounds 7a, 7b and 8 showed excellent antimicrobial activity.

Fused-Ring Oxazolopyrrolopyridopyrimidine Systems with Gram-Negative Activity

Fused polyheterocyclic derivatives are available by annulation of a tetramate scaffold, and been shown to have antibacterial activity against a Gram-negative, but not a Gram-positive, bacterial strain. While the activity is not potent, these systems are structurally novel showing, in particular, a high level of polarity, and offer potential for the optimization of antibacterial activity.

Nickel-catalyzed carbonylation of arylboronic acids with DMF as a CO source

By using N,N-dimethylformamide (DMF) as a CO source, nickel-catalyzed carbonylation of arylboronic acids was demonstrated as an efficient and facile protocol for the synthesis of diaryl ketones.

Synthesis, Biological Evaluation and Molecular Docking of Certain Sulfones as Potential Nonazole Antifungal Agents

We reported herein the synthesis, antifungal activity, docking and in silico ADME prediction studies of four novel series of sulfones 6a–f, 8a–c, 10a–f and 12a–c. All the newly synthesized sulfones were tested against four strains of Candida (including fluconazole-resistant Candida), two strains of Aspergillus, two dermatophytic fungi (Trichophytons mentagrophyte and Microsporum canis) and Syncephalastrum sp. with fluconazole as a reference drug. In general, compounds 8a and 10b showed selective and potent anticandidal activity (MIC: 0.19–0.81 µM) relative to fluconazole (MIC = 1.00 µM). Furthermore, 10e and 12a elicited a remarkable and selective antifungal activity against Aspergillus sp. and the dermatophytic fungi (MIC: 0.16–0.79 µM) relative to fluconazole (MIC: 2–2.6 µM). Moreover, the docking results of the sulfones 6a, 8a, 10a and 10b at the active site of CYT P450 14α-sterol demethylase showed a comparable binding interaction (interaction Energy = −34.87 to −42.43 kcal/mol) with that of fluconazole (IE = −40.37 kcal/mol).