A mild and efficient one-pot synthesis of 2-dihydroimidazoles from aldehydes

Synthesis of Antiprotozoal 2-(4-Alkyloxyphenyl)-Imidazolines and Imidazoles and Their Evaluation on Leishmania mexicana and Trypanosoma cruzi

Twenty 2-(4-alkyloxyphenyl)-imidazolines and 2-(4-alkyloxyphenyl)-imidazoles were synthesized, with the former being synthesized in two steps by using MW and ultrasonication energy, resulting in good to excellent yields. Imidazoles were obtained in moderate yields by oxidizing imidazolines with MnO2 and MW energy. In response to the urgent need to treat neglected tropical diseases, a set of 2-(4-alkyloxyphenyl)- imidazolines and imidazoles was tested in vitro on Leishmania mexicana and Trypanosoma cruzi. The leishmanicidal activity of ten compounds was evaluated, showing an IC50 < 10 µg/mL. Among these compounds, 27-31 were the most active, with IC50 values < 1 µg/mL (similar to the reference drugs). In the evaluation on epimastigotes of T. cruzi, only 30 and 36 reached an IC50 < 1 µg/mL, showing better inhibition than both reference drugs. However, compounds 29, 33, and 35 also demonstrated attractive trypanocidal activities, with IC50 values < 10 µg/mL, similar to the values for benznidazole and nifurtimox.

Synthesis of CF3-Containing 2-Imidazolines and Imidazoles via a Iodide-Promoted [3 + 2] Cyclization Reaction

We report herein a general and effective system achieving cyclization of β-trifluoromethyl enones with amidines in the presence of 1,3-diiodo-5,5-dimethylhydantoin (DIH), which affords a range of trifluoromethylated 2-imidazolines in synthetically useful yields with good diastereoselectivities (up to 95% yield, up to 98:2 dr) and good functional group tolerance. Furthermore, the one-pot synthesis of trifluoromethylated imidazoles via sequential cyclization and oxidation is demonstrated. More significantly, the reaction mechanism was verified by ESI-MS studies of possible intermediates, and a reasonable reaction mechanism was proposed.

Novel pirfenidone derivatives: synthesis and biological evaluation

In order to discover novel anti-pulmonary fibrosis agents, a series of novel pirfenidone derivatives were designed and synthesized. All compounds were investigated for their anti-pulmonary activity and characterized by 13C and 1H nuclear magnetic resonance and high-resolution mass spectrometry. Preliminary studies on their biological activity showed that all target compounds showed different degrees of inhibition on pulmonary fibrosis, and most of the derivatives were significantly better than pirfenidone.

Single-Step Sustainable Production of Hydroxy-Functionalized 2-Imidazolines from Carbohydrates

Manufacturing valuable N-containing chemicals from biomass is highly desirable yet challenging. Herein, a novel strategy was developed for efficient production of 2-(1-hydroxyethyl)-imidazoline (HI), a high-value and versatile building block for synthesizing a myriad of bioactive targets, directly from carbohydrates under mild reaction conditions. With this strategy, bio-based HI was produced from fructose in one step with as high as 77 C % isolated yield in the presence of ethylenediamine (EDA) and InCl₃ at 130 °C. The synergistic functions of EDA and InCl₃ were identified for the transformation, wherein EDA promoted the scission of C-C bond of fructose backbone via retro-aldol (R-A) reaction and rapidly trapped in-situ formed reactive carbonyl-containing C₃ intermediate for HI formation to avoid undesired side reaction, and InCl₃ facilitated the formation of this C₃ intermediate and the final 1,2-hydrid shift step.

Neutral sphingomyelinase 2 inhibitors based on the 4-(1H-imidazol-2-yl)-2,6-dialkoxyphenol scaffold

Neutral sphingomyelinase 2 (nSMase2), a key enzyme in ceramide biosynthesis, is a new therapeutic target for the treatment of neurological disorders and cancer. Using 2,6-dimethoxy-4-[4-phenyl-5-(2-thienyl)-1H-imidazol-2-yl]phenol (DPTIP), our initial hit compound (IC₅₀ = 30 nM) from nSMase2 screening efforts, as a molecular template, a series of 4-(1H-imidazol-2-yl)-2,6-dialkoxyphenol derivatives were designed, synthesized, and evaluated. Systematic examination of various regions of DPTIP identified the key pharmacophore required for potent nSMase2 inhibition as well as a number of compounds with the 4-(1H-imidazol-2-yl)-2,6-dialkoxyphenol scaffold with similar or higher inhibitory potency against nSMase2 as compared to DPTIP. Among them, 4-(4,5-diisopropyl-1H-imidazol-2-yl)-2,6-dimethoxyphenol (25b) was found to be metabolically stable against P450 metabolism in liver microsomes and displayed higher plasma exposure following oral administration as compared to DPTIP. Analysis of plasma samples identified an O-glucuronide as the major metabolite. Blockade of the phase II metabolism should further facilitate our efforts to identify potent nSMase2 inhibitors with desirable ADME properties.

Potentiation of the Fosmidomycin analogue FR 900098 with substituted 2-oxazolines against Francisella novicida

A library of 33 compounds was screened for potentiation of the antibiotic FR 900098 against the Francisella tularensis surrogate Francisella novicida. From the screen a highly potent 2-oxazoline adjuvant was discovered capable of potentiating FR 900098 with a 1000-fold reduction in MIC against the Francisella sub-species F. novicida and F. philomiragia.

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.

Fe3O4@SiO2@polyionene/Br3− core–shell–shell magnetic nanoparticles: a novel catalyst for the synthesis of imidazole derivatives under solvent-free conditions

New Fe₃O₄@SiO₂@polyionene/Br₃⁻ core–shell–shell magnetite nanoparticles were prepared using a co-precipitation method and were used in the syntheses of imidazole derivatives under solvent-free conditions.

Theoretical and experimental characterization of a novel pyridine benzimidazole: suitability for fluorescence staining in cells and antimicrobial properties

Imidazopyridine showed fluorescence properties suitable for imaging with both prokaryotic and eukaryotic cells.

Transition metal and base free synthesis of 2-aryl-2-oxazolines from aldehydes and β-amino alcohols catalysed by potassium iodide

Synthesis of 2-aryl-2-oxazolines from β-amino alcohols and aldehydes was achieved in good to excellent yield by employing a potassium iodide (KI)–tert-butyl hydroperoxide (TBHP) catalytic system.

Efficient Synthesis of 2-Imidazolines in the Presence of Molecular Iodine Under Ultrasound Irradiation

An efficient one-pot synthesis process for preparing 2-imidazolines from aldehydes and ethylenediamine using molecular iodine and potassium carbonate in absolute ethanol at 25–30°C under ultrasound irradiation is described. The synthetic strategy has the following advantages: mild conditions and low costs requirements, readily available catalyst, short reaction times, simplicity of operation, and good-to-excellent yields.

NIS-mediated oxidative cyclization of N-(2-trifluoromethyl-3-alkynyl) hydroxylamines: a facile access to 4-trifluoromethyl-5-acylisoxazoles

A NIS mediated sequential procedure involving oxidation and electrophilic cycloisomerization ofN-(2-trifluoromethyl-3-alkynyl) hydroxylamines for 4-trifluoromethyl-5-acylisoxazole synthesis is developed.

Efficient, Rapid and One Pot Synthesis of 2-substituted Benzimidazoles Using the NaOH/I2 System as an Oxidant Under Mild Conditions

A one-pot efficient synthesis of benzimidazole derivatives has been achieved from aryl aldehydes and o-phenylenediamine in the presence of the NaOH/I2 system at room temperature in acetonitrile. The simplicity of the procedure and work-up, larger scale synthesis, high yields and short reaction times are the advantages of this method.

Facile synthesis of tetracyclic azepine and oxazocine derivatives and their potential as MAPKAP-K2 (MK2) inhibitors

Facile synthesis of two new series of tetracyclic azepine and oxazocine analogs is described. These analogs were evaluated for their potential as MAPKAP-K2 (MK2) inhibitors and several were found to be potent at inhibiting MK2 with a non-ATP competitive binding mode.

Activated fly ash catalyzed facile synthesis of novel spiro imidazolidine derivatives as potential antibacterial and antifungal agents

An array of novel spiro imidazolidine derivatives was synthesized in dry media and was screened for their anti-microbial activities. Structure-activity relationship results revealed that compounds 22, 23 against P.aeruginosa, 24 against S.aureus, 24, 25 against K.pneumonia, 27 against S.aureus, β-H.streptococcus, 29 against M.luteus, K.pneumonia, 29, 30 against P.vulgaris exhibited excellent antibacterial activity at a minimum inhibitory concentration (MIC) value of 6.25 µg/mL. Compound 23 against M.gypseum, 25, 29 against Candida 6 and 29, 30 against C.albicans revealed excellent antifungal activity at a MIC value of 6.25 µg/mL.

[Development and application of practical synthetic methods of imidazolines]

This review describes the first method to prepare imidazolines from aldehydes and 1,2-diamines by condensation and successive oxidation using NBS in one-pot operation. The reaction proceeds under mild conditions and can be applied to various aromatic and aliphatic aldehydes and 1,2-diamines. The utility of this method is also demonstrated in the total synthesis of spongotine A and the preparation of a newly designed organocatalyst, C3-symmetric trisimidazoline 7.