Recyclable 2nd generation ionic liquids as green solvents for the oxidation of alcohols with hypervalent iodine reagents

Synthesis of phosphate stabilised iodanes and their application in intramolecular aryl migrations

A diverse set of hydroxy-benzo[e]iodadioxaphosphinine oxides and derived diaryl iodonium salts are prepared and two examples are characterized by X-ray crystallography, featuring an out-of-plane geometry of the hypervalent bond for both compound classes. Treatment of the phosphate-stabilized diaryliodonium salts with Ca(OH)2 results in an efficient base-induced intramolecular aryl migration under aqueous conditions, yielding iodo-substituted diaryl ethers with yields up to 94%. Our findings highlight the synthetic potential of this previously underexplored compound class in organic transformations.

Dess-Martin Periodinane-Mediated Oxidative Coupling Reaction of Isoquinoline with Benzyl Bromide

Dess-Martin periodinane (DMP) is a broadly applicable oxidant in chemical synthesis. In this work, an efficient and convenient synthesis of N-substituted isoquinolinone derivatives mediated by DMP was achieved through the oxidative coupling reaction of functionalized isoquinoline with readily available benzyl bromide, which is a metal-free, mild, and practical method for synthesizing isoquinoline-1,3-dione or isoquinoline-1,3,4-trione derivatives in excellent yields. The H₂O¹⁸-labeling experiment was performed to gain insight into the possible mechanism for this reaction.

The design of experiments (DoE) in optimization of an aerobic flow Pd-catalyzed oxidation of alcohol towards an important aldehyde precursor in the synthesis of phosphatidylinositide 3-kinase inhibitor (CPL302415)

Herein, we describe the development of a green, scalable flow Pd-catalyzed aerobic oxidation for the key step in the synthesis of CPL302415, which is a new PI3Kδ inhibitor. Applying this environmental-friendly, sustainable catalytic oxidation we significantly increased product yield (up to 84%) and by eliminating of workup step, we improved the waste index and E factor (up to 0.13) in comparison with the stoichiometric synthesis. The process was optimized by using the DoE approach.

Recyclable Hypervalent Iodine Reagents in Modern Organic Synthesis

Hypervalent iodine (HVI) reagents have gained much attention as versatile oxidants because of their low toxicity, mild reactivity, easy handling, and availability. Despite their unique reactivity and other advantageous properties, stoichiometric HVI reagents are associated with the disadvantage of generating non-recyclable iodoarenes as waste/co-products. To overcome these drawbacks, the syntheses and utilization of various recyclable hypervalent iodine reagents have been established in recent years. This review summarizes the development of various recyclable non-polymeric, polymer-supported, ionic-liquid-supported, and metal–organic framework (MOF)-hybridized HVI reagents.

1 Introduction

2 Polymer-Supported Hypervalent Iodine Reagents

2.1 Polymer-Supported Hypervalent Iodine(III) Reagents

2.2 Polymer-Supported Hypervalent Iodine(V) Reagents

3 Non-Polymeric Recyclable Hypervalent Iodine Reagents

3.1 Non-Polymeric Recyclable Hypervalent Iodine(III) Reagents

3.2 Recyclable Non-Polymeric Hypervalent Iodine(V) Reagents

3.3 Fluorous Hypervalent Iodine Reagents

4 Ionic-Liquid/Ion-Supported Hypervalent Iodine Reagents

5 Metal–Organic Framework (MOF)-Hybridized Hypervalent Iodine Reagents

6 Conclusion

Excellent Eco-friendly Selective Alcohols Oxidation by an Acid Functionalized Imidazolium Based Ionic Liquid

Aims:

A green route for the oxidation of alcohols to corresponding carbonyl compounds in room temperature ionic liquid ([CEMIM]BH4) was developed by using hydrogen peroxide as the oxygen source. In aqueous solution at room temperature, 0.2 mol% of ([CEMIM]BH4) showed excellent catalytic properties for selective oxidation of aromatic and aliphatic alcohols

Background:

One of the vital reactions in organic synthesis is the oxidation of alcohols to carbonyl compounds. In particular, the conversion of primary alcohols to aldehydes has received a variety of applications as they are used as intermediates in fine chemicals mostly for the perfume industry.

Objective:

In the present work, we have reported an effective green route for the selective oxidation of alcohols to the carbonyl compounds using peroxide in an ionic liquid 1-carboxyethyl-3-methyl-imidazolium tetrahydroborate ([CEMIM]BH4)

Methods::

A mixture of alcohol (2 mmol), ([CEMIM]BH4) (0.2 mol%), H2O2 (2 mmol) were stirred thoroughly with the help of a magnetic stirrer for 10 min at ambient temperature

Results:

The catalytic activity of ([CEMIM]BH4) is very effective, which reflects its good solvating nature during the oxidation.

Conclusion:

In conclusion, the series of experiments described represents a useful method for the oxidation of primary and secondary alcohols to carbonyl compounds at room temperature. The catalyst can be easily prepared and is therefore extremely cost-effective. The rapid reaction times for the substrates mean a large number of materials may be screened in parallel over a short period of time.

Facile one-pot synthesis of ketones from primary alcohols under mild conditions

One-pot transformation of primary alcohols to ketones was achieved by using dibromoisocyanuric acid and Fe₂O₃. This synthetic method provides a variety of ketones in high yield under mild reaction conditions.

Application of The Dess-Martin Oxidation in Total Synthesis of Natural Products

Dess-Martin periodinane (DMP), a commercially available chemical, is frequently utilized as a mild oxidative agent for the selective oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. DMP shows several merits over other common oxidative agents such as chromiumand DMSO-based oxidants; thus, it is habitually employed in the total synthesis of natural products. In this review, we try to underscore the applications of DMP as an effective oxidant in an appropriate step (steps) in the multi-step total synthesis of natural products.

"On water" palladium catalyzed diastereoselective boronic acid addition to structurally diverse cyclopropane nitriles

An efficient palladium catalyzed diastereoselective addition of arylboronic acids to complex spirocyclopropyl dinitriles is developed in the presence of a catalytic amount of 4-dodecylbenzenesulphonic acid (DBSA) as a Brønsted acid surfactant in aqueous media. The protocol is also found to be highly effective when different types of nitrile compounds and organo-boron compounds are used. The overall reaction has been found to be very cost efficient since it requires low catalyst loading, mild thermal energy and short reaction time. Wide substrate scope, operational simplicity, good to excellent product yield, and use of green solvents make the reaction a practical route to transform nitrile into a keto functionality in biorelevant heterocyclic scaffolds. The scale-up synthesis of the target scaffolds can also be achieved with ease which also signifies the practicability of this protocol.

Green chemical engineering in China

In China, the rapid development greatly promotes the national economic power and living standard but also inevitably brings a series of environmental problems. In order to resolve these problems fundamentally, Chinese scientists have been undertaking research in the area of green chemical engineering (GCE) for many years and achieved great progresses. In this paper, we reviewed the research progresses related to GCE in China and screened four typical topics related to the Chinese resources characteristics and environmental requirements, i.e. ionic liquids and their applications, biomass utilization and bio-based materials/products, green solvent-mediated extraction technologies, and cold plasmas for coal conversion. Afterwards, the perspectives and development tendencies of GCE were proposed, and the challenges which will be faced while developing available industrial technologies in China were mentioned.

The Use of Liquids Ionic Fluids as Pharmaceutically Active Substances Helpful in Combating Nosocomial Infections Induced by Klebsiella Pneumoniae New Delhi Strain, Acinetobacter Baumannii and Enterococcus Species

This review deals with various microbiological activities of ionic liquids, which constitute the first anti-infective defense against multi-drug-resistant bacteria-with a particular emphasis placed on medicine and pharmacology. The quoted data on the biological activity of ionic liquids including their antimicrobial properties (depending on the type of a cation or an anion) and are discussed in view of possible applications in nosocomial infections. Dedicated attention is given to finding infections with the Klebsiella pneumoniae New Delhi strain, Acinetobacter baumannii, and Enterococcus species, which are responsible for the induction of antibiotic resistance in intensive care units. Diagnosis and treatment using current antibiotics is a significant problem in hospital care, and the relevant burden on the health systems of the European Union member states induces the search for new, effective methods of treatment. Ionic liquids, due to their antibacterial effect, can be considered topical and general medications and may provide the basis for treatment to eliminate the antibiotic resistance phenomenon in the future. At present, the number of infections with resistant pathogens in hospitals and outpatient clinics in the European Union is growing. In 2015⁻2017, a significant incidence of respiratory and bloodstream infections with bacteria resistant to antibiotics from the 3rd generation group of cephalosporins, glycopeptides, and carbapenems were observed. The paper presents examples of synthesized bifunctional salts with at least one pharmaceutically active ion in obtaining a controlled release, controlled delivery, and biological impact on the pathogenic bacteria, viruses and fungi. The ionic liquids obtained in the presented way may find applications in the treatment of wounds and infections.

Synthesis and in vitro evaluation of hydrazinyl phthalazines against malaria parasite, Plasmodium falciparum

In this report, we describe the synthesis of 1-(Phthalazin-4-yl)-hydrazine using bronsted acidic ionic liquids and demonstrate their ability to inhibit asexual stage development of human malaria parasite, Plasmodium falciparum. Through computational studies, we short-listed chemical scaffolds with potential binding affinity to an essential parasite protein, dihydroorotate dehydrogenase (DHODH). Further, these compounds were synthesized in the lab and tested against P. falciparum. Several compounds from our library showed inhibitory activity at low micro-molar concentrations with minimal cytotoxic effects. These results indicate the potential of hydralazine derivatives as reference scaffolds to develop novel antimalarials.

Photocatalytic Oxidation of Benzyl Alcohols by Three-Dimensional Reduced Graphene Oxide/Nano Zinc Oxide Catalyst under Visible Light

A three-dimensional reduced graphene oxide/nano zinc oxide (3D-RGO/ZnO) composite photocatalyst has been prepared through an in situ reduction of GO and growth of nano ZnO particles process. The 3D-RGO/ZnO catalyst displayed enhanced photocatalytic activity towards commercial ZnO nanoparticles and can be applied to the oxidation of a broad series of benzyl alcohols including primary and secondary alcohols to corresponding carbonyl compounds under the irradiation of visible light. A plausible photocatalytic mechanism referring to photo electron generation and transfer has been proposed.

Fast measurement of methanol concentration in ionic liquids by potential step method

The development of direct methanol fuel cells required the attention to the electrolyte. A good electrolyte should not only be ionic conductive but also be crossover resistant. Ionic liquids could be a promising electrolyte for fuel cells. Monitoring methanol was critical in several locations in a direct methanol fuel cell. Conductivity could be used to monitor the methanol content in ionic liquids. The conductivity of 1-butyl-3-methylimidazolium tetrafluoroborate had a linear relationship with the methanol concentration. However, the conductivity was significantly affected by the moisture or water content in the ionic liquid. On the contrary, potential step could be used in sensing methanol in ionic liquids. This method was not affected by the water content. The sampling current at a properly selected sampling time was proportional to the concentration of methanol in 1-butyl-3-methylimidazolium tetrafluoroborate. The linearity still stood even when there was 2.4 M water present in the ionic liquid.

Esterification of carboxylic acids with alkyl halides using imidazolium based dicationic ionic liquids containing bis-trifluoromethane sulfonimide anions at room temperature

Task-specific RTILs of symmetrical N-methylimidazolium rings linked to an oligo (ethylene glycol) chain (cationic part) and bis-trifluoromethane sulfonimide (anionic part) were synthesized, and the physicochemical properties with catalytic activity were determined.

Synthesis and Biological Evaluation of Febrifugine Analogues

A series of febrifugine analogues were designed and synthesized. Antimalarial activity evaluation of the synthetic compounds indicated that these derivatives had a strong inhibition against both chloroquine-sensitive and -resistant Plasmodium falciparum parasites. Many of them were found to be more active than febrifugine hydrochloride. The tested analogues had also a significant cytotoxicity against four cancer cell lines (KB, MCF7, LU1 and HepG2). Among the synthetic analogues, two compounds 17b and 17h displayed a moderate cytotoxicity while they exhibited a remarkable antimalarial activity.

Organoiodine(V) reagents in organic synthesis

Organohypervalent iodine reagents have attracted significant recent interest as versatile and environmentally benign oxidants with numerous applications in organic synthesis. This Perspective summarizes synthetic applications of hypervalent iodine(V) reagents: 2-iodoxybenzoic acid (IBX), Dess-Martin periodinane (DMP), pseudocyclic iodylarenes, and their recyclable polymer-supported analogues. Recent advances in the development of new catalytic systems based on the generation of hypervalent iodine species in situ are also overviewed.

Syntheses of conjugated octadecadienoic acids

Three approaches for the synthesis of octadecadienoic acids with conjugated double bond systems are presented: synthesis of (10Z, 12Z)-octadecadienoic acid via an enyne-substructure; the use of an educt with a conjugated double bond system for the synthesis of (10E, 12E)-octadecadienoic acid; and the Suzuki cross coupling for the synthesis of (7E,9Z)-octadecadienoic acid.