Improved catalysis of Morita–Baylis–Hillman reaction. The strong synergic effect using both an imidazolic ionic liquid and a temperature

Discovery and structure-activity relationship of Morita-Baylis-Hillman adducts as larvicides against dengue mosquito vector, Aedes aegypti (Diptera: Culicidae)

Neglected tropical diseases (NTDs) have become a significant public health problem worldwide, notably the life-threatening dengue hemorrhagic fever borne by the Aedes aegypti mosquito. Thus, mosquito vector control measures remain essential in public health vector surveillance and control to combat Aedes-borne infections. Therefore, a series of MBH adducts were synthesized and assessed towards the fourth instar mosquito larvae, Aedes aegypti, along with the preliminary structure-activity relationship (SAR). Noteworthy, this compound class might be synthetized by an efficient eco-friendly synthesismethod and a rapid route for the synthesis of commercial larvicide through a single synthetic step. The bioassays showed that this compound class is a promising larvicide to control Aedes aegypti mosquito larvae, mainly 3g, with an LC₅₀ of 41.35 µg/mL, which was higher than evaluated positive controls. Nevertheless, it is a viable larvicidalhit candidate for further hit-to-leadproperties optimization of its biphenyl backbone scaffold with enhanced insecticidalbioactivity. Moreover, scanning electron microscopy analysis suggested a disruption of the osmoregulatory/ionoregulatory functions by the complete deterioration of the terminal exoskeleton hindgut and anal papillae. Therefore, this new study shows the larvicidal efficacy of the tested compounds against the Aedes aegypti larvae.

Versatile O- and S-functionalized 1,2,3-triazoliums: ionic liquids for the Baylis–Hillman reaction and ligand precursors for stable MIC-transition metal complexes

A series of O- and S-functionalized triazolium salts display high performance in the Baylis–Hillman addition and allow the one-pot formation of MIC-transition metal complexes.

Insights into the Morita–Baylis–Hillman reaction of isomeric dibenzofuran carbaldehydes: a theoretical and mass spectral study

Systematic theoretical and mass spectral investigations on the faster Morita–Baylis–Hillman (MBH) reaction of dibenzofuran-4-carbaldehyde (2) compared to its isomer, dibenzofuran-2-carbaldehyde (1) are described.

Ionic liquids and ultrasound in combination: synergies and challenges

The advantages and the limits of the ionic liquid/ultrasound combination for different applications in chemistry are critically reviewed to understand how it could become an essential tool in future years.

Remarkable influence of microwave heating on Morita-baylis-Hillman reaction in PEG-200

Background

Morita Baylis Hillman (MBH) reaction is used to introduce carbon-carbon or carbon-heteroatom bond in a molecule. The major drawback of this reaction is the relatively low product yield and long reaction time. Though notable changes have been made to improve the reaction rate and yield of MBH adduct by various groups, a reliable synthetic procedure under ambient temperature in presence moisture and air is remain unsolved. Continuing the effort to improve the rate and yield, we report here an eco-friendly and cost-effective method to generate MBH adducts. Non-volatile polyethylene glycol-200 is used as reusable solvents and the reaction was carried out under the influence of microwave energy.

Results

Microwave irradiation have a remarkable influence on PEG suspended 4-Diazabicyclo [2.2.2] octane (DABCO) catalysed MBH reaction between aldehydes and ethyl acrylate. Molecular weight of the PEG is found to have a significant influence on the reaction yield. PEG-200 was the most efficient solvent and in combination with DABCO, the medium can be recycled upto three more runs. This reaction condition is successfully applied to obtain MBH adduct of five different aldehydes in very short time with excellent yield and the required catalyst concentration was very low compared to standard MBH reaction. Since the MBH adduct is an important reactive intermediates for many complex organic syntheses, this approach can be successfully utilised as an alternative to existing reaction conditions.

Conclusion

A new method was developed to improve the reaction rate and yield of MBH reaction The PEG 200-DABCO combination provides a sustainable, non-volatile, recyclable and environment friendly solvent medium to produce MBH adducts. This medium in combination with microwave energy proved to be very effective to introduce a new carbon-carbon or a carbon-heteroatom bond in a molecule.

Baylis–Hillman reaction under solvent-free conditions — Remarkable rate acceleration and yield enhancement

A simple and efficient method has been developed for remarkable rate acceleration and yield enhancement of the Baylis–Hillman reaction under solvent-free “neat conditions” and solvent-less isolation of products. Reaction of equimolar quantities of aldehyde and olefin in the presence of 20 mol% of DABCO under neat conditions affords the highest yield in most cases within the shortest reaction time, giving support to the mechanisms of proton transfer in protic and aprotic solvents. Solvent-free conditions are found to be especially fast, selective, and high yielding for aromatic aldehydes.