Ketones - Science topic

But in my product spot in tlc, starting compound thai is chalcone is also present which is not getting consumed even after 17hrs of reflux. Is there any way to remove the unreacted chalcone from the product by means of extraction or other way,without going for column chromatography

Foe my research as a professor at a small college, I was asking the same question, but I assumed the same answer as Abdelhak Maghchiche. If I look at my files I probably have a reference for it.

As mentioned above, Fluorinated polymers are good candidates. You may look at fluorosilicones, If you look at the cheapest material, you may check polyethylene which does not easily degrade. However, it will get fouled. Another way to reduce the cost is to use glass fiber composite of PU, or other material as mentioned above.

If your starting materials (a ketone and 1,10-phenanthroline-5-amino) are not very soluble in methanol or ethanol, you might consider using alternative solvents that are more effective in dissolving these compounds. Here are a few suggestions:

1. Dimethyl Sulfoxide (DMSO):

- DMSO is a highly polar aprotic solvent that can dissolve a wide range of organic compounds. It might improve the solubility of your starting materials.

2. Dimethylformamide (DMF):

- DMF is another polar aprotic solvent known for its ability to dissolve many organic substances, including those that are poorly soluble in methanol or ethanol.

3. Acetonitrile (MeCN):

- Acetonitrile is a polar aprotic solvent that is less polar than DMSO and DMF but can still dissolve many organic compounds.

4. Tetrahydrofuran (THF):

- THF is a moderately polar solvent that is often used in organic synthesis. It can sometimes dissolve compounds that are not soluble in alcohols.

5. Chloroform (CHCl₃) or Dichloromethane (DCM):

- These non-polar solvents might help if your compounds have significant non-polar character.

Photocatalytic processes are very complex. The selective scavenge of formaldehyde does not exist. An addition of whatever chemical to the system will make the system more complex. In order to better understand the role of formaldehyde, try to add some known amount of formaldehyde and see what happens.

For hydrogen bonding you need OH or NH groups. The bands are more likely due to structural symmetry or asymmetry. Looking at ref spectra of Acetone (1) the higher band is seen as a shoulder, not easily explained other than small methyl molecules do have prominent normally weak bands (Fermi resonance ?) There is a danger in looking at expanded short areas of spectra without seeing the full spectrum. I would have guessed that the doublet in the diones was due to symmetric and asymmetric stretching of he carbonyls. However a Aldrich reference spectrum of 2,4-pentadione shows a small doublet at 1700cm-1 but the strongest broad band is at 1630 cm-1 and other bands in the 3200- 2000 cm-1 also indicate OH. Other diketones are similar. This implies that the diketones actually have an enol structure. You need to see the full spectra to try to make sense of the published short spectra.

Hello RG Community subsequent to inquiries I will recommend to myself and other to complete all Tabs of ffTK and or ffParam and or use experimental evidence.

Joel 🚀

Dear Ja M.

In general, the formation of imines (including alpha, beta-unsaturated imines) in apolar and aprotic solvent requires the presence of a catalyst that will help in the transfer of protons in the steps of carbinolamine formation and in its decomposition. In a recent study by our research group, it was verified that methanesulfonic acid has a superior performance than acetic acid, making it possible to use relatively low amounts of this catalyst (Rufino, V. C.; Pliego Jr, J. R. J. Braz. Chem. Soc. 2023. https://dx.doi.org/10.21577/0103-5053.20230063). Experimentally, molecular sieves are also used as additives (A. D. J. Calow, J. J. Carbo, J. Cid, E. Fernández, A. Whiting, J. Org. Chem. 2014, 79, 5163).

Some works of our research group in which the investigation of the reaction mechanisms of imine formation in aprotic solvent was conducted:

Rufino, V.C.; Pliego Jr., J.R.; Computer Theor. chem. 2020,

1191, 113053. https://doi.org/10.1016/j.comptc.2020.113053

Rufino, V.C., Pliego, J.R., J Phys Org Chem 2023, 36(3), e4467. https://doi.org/10.1002/poc.4467

Rufino, V.C.; Pliego Jr, J.R.J. Braz. chem. Soc. 2023. https://dx.doi.org/10.21577/0103-5053.20230063

I am not sure, but this reagent can undergo intramolecular rearangement in the presence of Lewis acids.

I think that both of the approaches you mention are viable options. Normalization by total peak area (also sometimes called "total sum normalization") is definitely a recognized approach, though there are also some problems with it. For example, you may overlook true differences between treatments if the total scale of the emissions is very different. Perhaps less obviously, an increase in the abundance of a single peak will reduce the relative intensity of all the other peaks in your chromatogram. Similarly, if you have a lot of differentiation between your samples with respect to the total number of peaks, this could also bias your results. In general, total area normalization is probably more valid if your chromatograms are fairly similar to each other. Nevertheless, total sum area normalization is fairly common in untargeted studies (probably 2nd only to internal standard quantification, which can also come with its own problems).

There are also some other potential options that have been proposed to normalize signal intensity without using an internal standard: e.g. median normalization and probabilistic quotient normalization. You might be interested in looking at the probabilistic quotient normalization. It purports to be a less biased approach to normalization of peak areas without using an internal standard. If you want to read into it, there have been a few papers looking at he effects of different normalization methods using real and/or simulated data:

P.S. I enjoyed your PIG talk the other week. Very cool work you all are doing with the Silphiums.

Dear Shruti Dubey, I think no, but DMF and THF did. Please have a look at the following documents. My Regards

For the standard curve, the best is a logistic fit. For the data points (replicates), calculate mean +/- SEM. For comparing individual samples, use a statistical model appropriate for your samples. That depends on the question you want to answer and what kind of samples you have. Follow the Wizard of your preferred statistical tool or better talk to a statistician.

The most important point to consider is the MW threshold for entanglements, which generally induces the gelation (uncomplete solvation). So the concentration should be as low as possible to allow disentanglements (time). Please have a look at the following free RG document. My Regards

Dear Gaurang,

thank you for sharing this very interesting chemical question on RG. As a synthetic inorganic chemist I'm certainly not a proven expert in the field of organic synthesis. I think that Greg Petruncio already provided some useful hints. Did you follow a published procedure? In any case, it seems that hydrogenation of the ketone seems to be a rather common side reaction of the McMurry coupling. For more information, please have a look at the following potentially useful article:

Unfortunately this paper has not been posted as public full text on RG. perhaps you can access it through your institution.

Good luck with your work!

Thank you! Will try it later!

If I remember well, this column works better for fatty acids. For light hydrocarbons, try another column.

Dear Noha,

many thanks for sharing this very interesting chemical problem with the RG community. Of course it is very difficult to judge from the outside what perhaps went wrong in your case. I assume that you followed a literature preparation. In this context, please have a look at the following potentially useful articles:

and

(please see attached pdf file)

As I said, an outsider can give you only unspecific advice. Try to make sure that all solvents are carefully dried and that the reaction is carried out under nitrogen or argon. I assume that small amounts of moisture can deactivate the catalyst. Sometimes the order of adding the reagents can also play a role.

Good luck with your work and best wishes!

Use Least Squares analysis

Dear Khurshed Bozorov many thanks for this very interesting technical question. When you hear McMurry reaction, you immediately think of low-valent titanium as coupling reagent. However, according to the link cited below, a number of other metals can also be employed as metal reagents in this reaction. These include e.g. aluminum, zirconium, vanadium, niobium, molybdenum, tungsten, and zinc. The respective original research articles are cited in the following link:

check the following review:

Hi@Alexander Sinko

I agree with the answer added by Dr. Kakuyou Ogawa, that there is a toxicity dose for every compound. Hence, LD50 assays are recommended to evaluate the toxicity of test compounds.

Check https://www.imedpub.com/articles/studying-the-effects-of-supplementing-reashure-to-pregnant-sheep-on-incidence-of-ketosis-and-health-status-pre-and-after-lambing.pdf

Dear santo,you can remove N- boc in excess boiling water at 100 C (373 K).

I think, you might use GC-FID indeed but for a more accurate analysis of your hydrocarbons, I would use a mass spectrometer (especially when you are working at low pressure but there are nowadays also MS for atmospheric pressure applications).

Ask your laboratory colleague who works on the HPLC.

Couple of months before, I helped some medical students in data analysis of similar research and have mentioned some of the research outcome in the answer. I will check with them if they are willing to share their research outcome with you. Though the sources are not mentioned, still you can also check the following link for detail: https://www.webmd.com/diet/guide/high-protein-low-carbohydrate-diets

Dear Dávid - You're very welcome. Perhaps, as a compromise so to speak, it might be worth a try to use methylglycol (ethylene glycol monomethyl ether) as a solvent for your steroid ketone. It should be less polar than ethylene glycol itself but it should still be able to form hydrogen bonds.

Insha ALLAH I will give your regards to Dr. Afsar Khan and Thank you for supporting me.

Try heating the mixture. Prior to adding polymer, dry it completely in the oven at 50-60 C.

I would suggest to do derivatization of amine first, then proceed with acid-catalyzed hydrolysis - unless the product of amine derivatization is acid-sensitive (or, if the derivatization procedure is incompatible with your lactam ring).

However, it is only a general recommendation, the situation may change depending on the structure of the desired final compound (i.e., what exactly you want to attach to amine).

Carboxylic acid derivatives are subjected to Wolf-Kishner reduction , the reduction of C=O will not occur and unwanted product may be formed.

The problems in removing m-cpba and its corresponding acid .MCBA is used as a oxidizing reagent and the byproduct of the reaction is m-chlorobenzoic acid. It is soluble in aq. NaHCO3. However , your product is not soluble. The solid product is different acid. Identify by IR,PMR, CMR and Mass data.

Dear Alan

Can you please attached the proposed synthetic scheme to clarify your question and point my answer?

Regards

If sodiumcyanoborohydride not works go with first ketone protection, then oxime reduction and ketone depotection.

This is no question although there is a question mark at the end.

Please ask serious scientific questions.

Otherwise I will answer to your question " Shall we prepare organic derivatives from Schiff base, only many iorganic complexes were reported?": No, get out this afternoon and play football (not cricket)!

I do not think so.

Tried it already on SciFinder. Result: Nothing

Dear Samrat Sahu,

For the synthesis of alpha, beta-unsaturated aldehydes from ketones, I don't have an answer. But, from a ketone bearing a quaternary carbon in alpha, I suggest you to see this patent whose the international publication number is WO 2012/129384 A2 by Colby David A. Riofsky Mark V. and Han Changho. I personnaly carried out this synthesis and it is powerful.

What grade of PEEK are you using. Is it Victrex 450G? In literature VICTREX 450G film grade peek is widely used.

Shiv Kumar Yadav Alcohols undergo esterification in the presence of acetic acid.

Hi Sharbel;

In organic chemistry, potassium dichromate is a milder oxidizer than sodium permanganate.

In KMnO₄, Manganese is in an oxidation state of (+7), reason why the KMnO₄ is a strong oxidizing agent (the elements become more electronegative as the oxidation states of their atoms increase). In addition, the most powerful oxidant will have the highest standard reduction potential (E0). For the (Mn⁺⁷/Mn⁺² you have E₀ = +1.51 V).

MnO₄^- (+7) + 8H⁺ + 5e-® Mn²⁺ (+2) + 4H₂O

In Na₂Cr₂O₇, Bichromate is in an oxidation state (+6), For (Cr⁺⁶/Cr⁺³), E₀ = +1.33 V.

Cr₂O₇^2- (+6) + 14H⁺ + 6e- ® 2Cr³⁺ (+3) + 7H^₂O

This is why the oxidation of fluorene by the Na₂Cr₂O₇/CH₃COOH mixture (mild conditions) ends at the stage of the carbonyl function.

With my best regards

Dear you can use chromatography

Dear Alexxandra,

very good thinking. In aqueous solution, fructose is an open-chain to a small extent and is present predominantly as α- or β-fructopyranose, which partially merge by mutarotation. In crystalline form, fructose exists as a closed pyran ring (fructopyranose). The keto group which is only present in fructose's open chain form has now turned into an OH- group by nucleophilic substitution during ring formation. Therefore, the keto group doesn't play any role in incorporating water into fructose's crystalline structure. Crystals of fructose exist as either anhydrous β-d-fructopyranose or as the dihydrate or hemihydrate (one molecule of water of crystallization per two molecules) of β-d-fructopyranose. Dihydrate fructose crystals can dissolve in their own water of hydration and must therefore be handled very careful. By the way, the water of crystallisation is not chemically bound, but only weakly bound by hydrogen bonds (electrostatic forces) and may normally be removed by heating.

Wishing you best of success,

Johannes

Dear Freyllerman Javier Barona Oliveros, would you please check these links. My Regards

https://www.ncbi.nlm.nih.gov › articles › PMC6419043

Hi. How about 1,3-diketone ?

Such as -----> Tris(acetylacetonato) iron(III)

Anhydrous SnCl2 in anhydrous EtOH under reflux

Baskar, R.; Gopiraman, M.; Kesavan, D.; Kim, I. S.; Subramanian, K. Synthesis, Characterization, and Electrochemical Studies of Novel Biphenyl Based Compounds. Ind. Eng. Chem. Res. 2012, 51, 3966–3974, doi:10.1021/ie201470j

ReactIR (aka in situ IR) is the best way to monitor intermediate species in a reaction. However if you do not have that, thin layer chromatography is your cheapest option that might show you conversion of phosphonium salt and formation of ylide.

dibal -h quenching with amonium chloride solution what by product form in solid form.

Thanks James. I agree with you and a nucleophile (including water), that is required to cleave acetal (dioxolane), is absent in my suggested conditions (HCl / AcOEt).

Hello Sa, tetraethylmethane ketone probably does not absorb light at 365nm. This could be observed on its UV absorption spectra. Pick a photoinitiator that absorbs light at 365 nm.

If you still want to use tetraethylmethane ketone, you need to use lower wavelength light which will be absorbed by the photoinitiator.

Also because your monomer concentration is low, be sure to remove oxygen to prevent quenching.

Thank you very much for your answers.

Sajjan Parajuli Have you been on vacation? It is 2 months since you posted your question so the answers obviously are of low priority to you.

'Nanopowder' is an oxymoron - there are no free, independent, discrete particles < 100 nm in a powder. You have a fused mix of post- and sub-micron aggregates and agglomerates. The steps in making a stable dispersion (well-known to paint and ceramics chemists) are wetting, separation, and stabilization. Like prefers like and a hydrophobic material will need to be wetted with a hydrophobic liquid. The key step is separation which requires energy. You will need a charge or steric stabilizer to keep the material from aggregating due to irreversible van der Waals effects.

Hello.

In principle, you can dissolve it in anything where it is soluble which is also water-mixable. Here's an example where they dissolved it in acetone:

Cheers

One thing I'm rather confused is if the Luche reduction will be selective enough to not reduce the sulfinyl group. The t-bu group may provide steric hindrance, but the selectivity the reaction has over aldehydes is because of the solvent forming an acetal, so I'm simply unsure wheter the t-bu group will protect the sulfinyl group.

I saw quite a few papers in which they used Zinc instead of Cerium, because of it's complexating nature it provides greater diastereoselectivity by complexating with neighbouring atoms asides from the ketone.

Since you're working with 3 conjugated double bonds that can be reduce, I think using a hard lewis acid like Ce or Zn is the most likely way to go, like I said, I'm just unsure if the sulfonyl will not be reduced since it's often ignored when talking about carbonyl-type reductions.

As we know, supercapacitance is a surface phenomenon, so any functional group attached to the surface influence the capacitance value.

The functional groups attached to the surface act as defects/adsorption sites and while charging and discharging, electrolyte cations and ions get adsorb and desorp to the surface as well as the extra adsorption sites(functional groups), thereby enhance the capacitance value.

الكيتونات التي فيها مجاميع فعالة أخرى تتأثر بالوسط الحامضي لا يمكن اختزالها بواسطة اختزال كليمنسن

The line broadening in FTIR spectra could be due to changes introduced in the chemical environments when a specific element (H, C, etc.) may be bonding with other chemical groups (e.g., extensive hydrogen bonding is observed with other hydroxy groups, etc.). The chemical groups may be within the same molecule (intramolecular bonding) or they may exist between neighboring molecules (intermolecular bonding). In any case, the impact of bonding of an element (e.g. H, C, etc.) is to produce measurable band broadening, which may be accompanied by changes in the mean absorption frequency (often lowering the mean frequency). You may look at the following publication on “Interpretation of Infrared Spectra, A Practical Approach” as an example using the following link: http://www3.uma.pt/jrodrigues/disciplinas/QINO-II/Teorica/IR.pdf

One may also compare FTIR spectra with Raman Spectra and look for changes in the Raman peaks associated with the related bonds. The IR forbidden lines often appear in Raman spectra due to local bond perturbations and broken bond symmetry. IR spectra are representing atomic motions producing dipole radiation that is normally not Raman active mode, while Raman active modes are produce by changes in the polarizability, which normally are IR forbidden mode. However, changes in local bonds allows for appearance of ordinary forbidden modes in the Raman spectra that can be linked back to changes in the bond associated with the related IR mode.

Thankyou @Eugene Yang

i have done lab studies with enzymses but coudnt get results.

ketones also can be subjected to knoevenagel condensation. Catalytic system of piperidine along with acetic acid is well known for this reaction. this reaction proceeds via Ionoc liquid formation in-situ. You can refer the following papers.

10.1021/acs.jpcb.7b03191

for lewis acid catalysed knoevenagel condensation

It can be considered experience ESD problems with PEEK as insulator bacause the PEEK materials that are conductive to improve ESD problems and this is due to the characteristics and properties of each of them in addition to the negatives and positives,the advantages & cons of each of them.

Thank you for the response. I had already reviewed this article. I was hoping someone had experience outside of the in going trials regarding dosage.

Best Regards. MEM

Please check

It has been recommended that the bicarbonate bath be adjusted to correct the predialysis serum bicarbonate concentration to prevent complications related to metabolic acidosis. It has been reported that a U-shaped relationship exists between the predialysis serum bicarbonate concentration and mortality in ESRD patients on dialysis. Those with a bicarbonate concentration < 18 mmol/L and > 27 mmol/L are at greatest risk. However, the study also reported that after adjustment for confounding factors such as nutritional status and inflammation, only a low pre-dialysis bicarbonate concentration remained a significant risk for death. The sweet spot for the predialysis serum bicarbonate seems to be from 18-23 mmol/L. So to answer your question, get the serum bicarbonate above 17 mmol/L using the 35 mmol/L bath.

See the following paper:

I suggest to use the method published long ago by Prof. Gilbert Stork (Columbia university, US) that involve reaction with lithium in liquid ammonia followed by insitu allylation. Be aware of possible competing O-allylation.

If you need more detail email at alain.krief@unamur.be. Hope the best

hipofisis tumor?

Given those compounds possess little to no UV absorbance and are very non-polar (requiring elution with hexanes whch would probably interfere with detection), I suggest gas chromatography may be a better choice.

election ionization mass spectrometer would be my detection choice.

Another possibility might be non-aqueous reverse phase (C18 or C30) with an ethanol to dichloromethane gradient, but I think the GC would give better resolution.

Hi:

Your question is a bit difficult to answer not knowing the organocatalyst you use, or a little more information on your substrate scope. However, the most common reasons for large %ee differences are the differences in the available conformers in the transition state. For example, the hydroxyl group may also coordinate to your reducing agent and force a single approach of the hydride to the ketone. I would suggest modeling your organocatalyst bound with your reducing agent (in whatever way is chemically plausible) and see which face of the different acetophenoes is accessible. This may be done very simply by using a model kit and much more complexly though TS calculations.

Good Luck!

Assuming that there are no other functionality that will interfere with the reaction, the difficultly is usually in achieving complete reduction for both.

Colloidal Palladium Nanoparticles with In Situ H2: Reducing System for α,β-Unsaturated Carbonyl Compounds

This paper seems to be able to do the reaction as a single step, but is still dependent on other factors.

I think the best bet will be using NaBH4 and varying the solvent and/or additive to achieve your desired conversion.

One can try condensation using Niobic acid (HNbO3), derived from Nb2O5 I hop[e it will behave like P5O5 and enol form of ketone will under go condensation.

perhaps

Thanks for suggestions from Abdul and Anton, their approaches are worth trying. Besides, I 've also found that using DBU as base under a carefully controlled reaction duration could achieve hydroxamic acid as the major product from according methyl esters. see reference:

Butyllithium will show two properties  as a base and neucleofile where grignard will show only nuecleophilic character and very minute basic character.so,Grignard is the best reagent.

Hi , what is your aim ?  you looking for org.solvent to make chemical reaction ? if yes ..what is your suggested product ?

Hello Jason Hyeonpil Cheon,

Are you in South Korea ?

I am also an international student in Seoul and searching some companies from where I can purchase PEEK and PET sheets for my research. Will you please suggest me some Korean websites for my purchase ??

Thanks Laith, I already have most of these papera but they don't explain why S. aureus doesn't need to perform beta oxidation of fatty acids!

But thank you anyway!! :)

@srinivas Kotha, 

Try this reference, Similar to your procedure but they use water as solvent instead of toluene.