I would start by following an analytical procedure for analysis of naproxyn-type molecules, like the following open-access article, then see if it can be scaled up:

Ru/Me-BIPAM-Catalyzed Asymmetric Addition of Arylboronic Acids to Aliphatic Aldehydes and α-Ketoesters

by

📷Yasunori Yamamoto

*,

📷Tomohiko Shirai

,

📷Momoko Watanabe

,

📷Kazunori Kurihara

and

📷Norio Miyaura

Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, kita 13, Nishi 8, Kita-ku, Sapporo 060-8628, Japan

*

Author to whom correspondence should be addressed.

Molecules 2011, 16(6), 5020-5034; https://doi.org/10.3390/molecules16065020

Received: 31 May 2011 / Revised: 13 June 2011 / Accepted: 15 June 2011 / Published: 17 June 2011

(This article belongs to the Special Issue Catalytic Asymmetric Synthesis)

They use normal-phase HPLC with a Chiracel-OD column, and mobile phase of 1/99 2-propanol/hexane.

Thanks Louis for the information you provided but I actually would like to do an asymmetric synthesis in mild conditions, staying away from heavy metals.

Try preparative chiral LC columns.

Hi Andrei.. I did try it but didn't work.

thanks for your reply..

Dear Nourah Alshahrani, try to make a transition from an enantiomeric mixture to a diastereoisomeric mixture by doing an esterification reaction

seeing that your molecule contains a hydroxyl group, so you can add a chiral molecule (R or S) bearing a carboxylic group, so you will have obtained a diastereoisomeric mixture and in this case you can separate them easily and then make a saponification reaction, but care must be taken to try to choose a group that can easily be eliminated than the ethyl ester.

Good luck!

Hi Nourah, if You have sufficient amount of the material first try to hydrolyse the ester to the free acid. Than try to precipitate its salt with some chiral amines. Maybe one chiral salt occur to be less soluble than the other.

Cheers,

Piotr

There is an alternative to LC, but it is also a column method to separate enantiomers. First, is OH-ENPPA soluble in water, If so continue, I presume your carboxylate must be slightly soluble. So lets make a separative column (lets say 500 ml) filled with a DEAE-Sepharose CL, or cross-linked cationic bed. It separate by size and charge of your racemic mixture, the best choice for amino-acids and peptides. https://en.wikipedia.org/wiki/Sepharose

https://doi.org/10.1016%2F0003-2697%2884%2990519-0

You have to choose what pH you going to place the column and the sample, so they both be ionized (R-COO anion and DEAE-Sepharose protonated). Both enantiomers of OH-ENPPA are going to bind tightly to the DEAE-Sephadex, by charge . The specificity of the polysacharide (support) to one enantiomer is given by the chirality of the support, so ALL YOU NEED TO DO is to elute (milk out) one of your enantiomers very slowly with a linear gradient of (ionic force) salt, like NaCl or KCl. As the products are passing through the column, one of them is going to be retarded. https://en.wikipedia.org/wiki/Gel_permeation_chromatography

Then you set up a device (automatic collector) to receive the eluate in different containers. You shall monitor the presence of one enantiomer using your DOR or CD spectrometer, so you shall be ready to separate one enantiomer in one flask and the other in another flask. IT WORKS, I warrant it, but first try in a small scale (column) to get the timing, the detection method and ion strength to use. Let the brothers move slowly through the column. You may find the DEAE-Sephadex you need already packed.

Alternatively, the crystallization may work if you use strychnine (POISONOUS cationic base). You shall make a salt of (Strichnine,OH-ENPPA). Just be very careful with "Strichnos", don't put the blame on me if you end up 6 feet under. No chewing gum, snacks of beverages in the lab! Or simply don't even try this method. "Strichnos" is bitter but no many dudes can remember that. Good luck. https://en.wikipedia.org/wiki/Strychnine_total_synthesis

Thank you Abdelmoula el Abbouchi , Piotr Krzeczyński and Victor Calvo-Perez

really appreciate it..

I am actually looking for asymmetric synthesis by using suitable chiral catalyst and not resolution.

Did you try crystallization!? Chiral columns and 3D HPLC? Hydrolysis of the ester and adducts formation leading to separation/ physical state changes! Fractional distillation, if that's liquid!!

In an experiment to study solvent extraction efficiency, a student performed

the following, using 1g of solute dissolved in 100 mL of water in each case:

(i) a single extraction with 100 mL of organic solvent.

(ii) a single extraction with 25 mL of organic solvent.

(iii) Four successive extraction with 25 mL portions of organic solvent.

Show that extraction step (iii) was the most quantitative.

Please help

This is a new question, not an answer.

This Gate is going like Twitter, this is NOT A QUARREL. How can I ban aggressive researchers?

Or maybe I shouldn't help NO MORE QUESTIONS? Inexperienced dudes.

Please used chiral preparative Hplc. You can obtain separatly the enantiomers. Good luck