Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

Ionic liquids (ILs) mediate fast, simple and cheap access to 1,6-ketoesters in high diastereoselectivities and good yields. The reaction protocol is robust and the 1,6-ketoesters can be obtained in gram scale after a simple filtration protocol. Moreover, the 1,6-ketoesters are potent gelators in hydrocarbon solvents.

The overall goal of this procedure is to illustrate how ionic liquids can be used as n Heterocyclic Carbine or NHC precursors in a three component synthesis of one six Keto esters, a new class of low molecular weight gel. Later, We are depending on complex molecules in our daily life. Everything from pharmaceuticals to new materials.

To find new molecular features, the synthetic toolbox needs to be expanded. The main advantage of the technique that you will learn here today is that it allows for rapid and inexpensive engineering of new materials with a desired function from readily available starting materials such as ionic liquids, ketones, ides, and alcohols. Generally, ionic liquids are considered as poor and see pre catalysts.

However, ionic liquids have many virtues, such as price and availability. Here represent a reaction where iron liquids are more selective and higher yielding than conventional NHC pre catalysts. To begin dry one ethyl three methyl oleum acetate or emac in a round bottom flask on a rotary evaporator at 10 millibar and 40 degrees for one hour.

Then add 2.1 grams of dry emac and one gram of calco to a 100 milliliter round bottom flask equipped with a magnetic stir. Also, add two milliliters of methanol and 2.3 grams of aldehyde to the flask. The edition sequence is of great importance.

DBU must be added last to ensure reproducibility At room temperature. Dissolve the mixture in 60 milliliters of chloro methane by stirring for one minute. Subsequently, add 0.37 milliliters of DBU to the stirring mixture and cap the round bottom flask.

Stir with a magnetic stir bar at a speed of 500 RPM at room temperature. Check for completion of the reaction with proton nuclear magnetic resonance or NMR. Look for the disappearance of the double bond of Cal C in the 7.8 PP M area.

When the reaction has reached completion, remove the volatiles on a rotary evaporator at 10 millibar and 20 degrees Celsius for 15 minutes. Add 50 milliliters of methanol to the residue and dissolve the EMAC by stirring with a magnetic stir bar. Remove the solids from the walls of the flask by stirring violently with a magnetic stir bar at a speed of 750 RPM for 30 minutes.

If necessary, use a spatula to remove the remaining solids from the walls. Filter the mixture on a fritz with a pore size of three. Setting aside the filtrate for Emmy Mac recycling.

Wash with an additional 40 milliliters of methanol still on the fritz, gently divide the filter cake into smaller pieces with a spatula. Transfer the solids via a powder funnel to a pre weighed round bottom flask and dry the solids under vacuum. Weigh the flask and calculate the yield.

Analyze the product by proton NMR and compare with reported spectra. Remove the volatiles from the methodol mixture under reduced pressure of 10 millibar at 40 degrees for 30 minutes. Analyze the resulting oil by proton NMR to check that EMAC is present.

The recycled EMAC can now be reused. Ululation prepare a stock solution by adding 200 milligrams of the synthesized product. Add a magnetic stir bar to a vial and 2.5 milliliters of chloro methane to dissolve the keto eter stir until everything has dissolved.

Then add 20 milliliters of Heptane to a 50 milliliter beaker and add 1.25 milliliters of the stock solution to the heptane Stir swiftly to ensure adequate mixing, and let's stand without stirring at ambient temperature until duration occurs. Dalal Oleum were used as pre catalysts in the formal conjugate edition of Unsaturated Aldehydes to Cal cones giving one six Keto esters. Emmy Mac promotes a highly stereo selective reaction between Aldehyde and Cal cone.

The reaction occurs with a high preference for the anti DSR and the one six keto esters can be isolated and yields up to 92%The three component reaction is monitored via proton NMR. The disappearance of the cal cone indicates that the reaction is finished as shown in the crude NMR following further purification of the product. The one six Keto Eter end product is analyzed by proton NMR and carbon 13 NMR, and compared with reported spectra Once mastered, it is possible to scale up the reaction.

Conventional problems associated with scaling are circumvented due to the chromatography free workup following this procedure. Other one six keto esters may be obtained. Structural variation within the aromatic rings are well tolerated, although none of the used reagents require special handling, good laboratory practice should be maintained.

After watching this video, you should have a good understanding of how to perform ionic liquid meditated synthesis of one six key rosters and how to formulation with these compounds.