Science topics: Organic Synthesis
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Organic Synthesis - Science topic

Procedures and advances in the organic synthesis of organic compounds
Questions related to Organic Synthesis
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In my schiff base there is a impurities, which is n,n-dimethylaminobenzaldeyde. I want to seperate the compounds by column chromatography. Now which solvents, and what ratio I should use? The other precursor is p-anisidine. The schiff base is soluble in water, ethanol, methanol but insoluble is n-hexane, diethyl ether.
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Find your solvents and ratio using TLC. Really it will be in "borders" from DCM, to MeOH... But the main (!!). Your solvents and SiO2 have NOT to content any traces of acid. Else - your Shiff base will be hydrolised
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As you can see in the picture, the reaction may involve Phenol to produce benzoxazole based product.
What can we do to react Amine with Aldehyde to produce related Imine without involving Phenol in the reaction? Any particular catalyst, synthesis method, solvent etc.?
If you know any related research paper, please feel free to mention it in your comment.
Thanks a LOT
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Carbonyl and amino group can easily generate Schiff base (imine), the reaction is a dehydration reaction, the carboxyl and hydroxyl groups in the reactants have no effect on the reaction, please note:
  1. The most commonly used solvents are ethanol or methanol
  2. Advantageous reactions need to be heated or added to activate the carbonyl group by adding Lewis acid
  3. 3. Reactants and solvents try to select the dehydrate
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There is a Michael acceptor in one substrate that could potentially react with amine in the second substrate, how can I block this reaction? is there any blocking group for Michael acceptor.
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If you can't block the amine, you can try to react your avid Michael acceptor with a removeable Michael donor, for example thioacetic acid. Then run your reaction and have as the last step, addition of a base stronger than triethylamine (a Hünig's base like N,N-diisopropylethylamine), which should remove it, restoring the double bond. Thiobenzoic acid may also work, and has the advantage of being UV active so you can quantify the formation of the thiobenzoate ester by TLC or HPLC. Then when the protection is completed, you could run the reaction you want, then deprotect with base. The protection-reaction-deprotection could then be performed in one pot. The main downside is the stench of thioacids, but you are probably working in a hood with a good draft and you could prepare for the reaction by setting up a large plastic container as a bleach bath for soaking all your stinky glassware and stir bars etc. prior to cleaning them.
Along the same lines of blocking the Michael acceptor with a dummy Michael donor, you could try good but bulky nucleophiles like benzamidine. Removal could then be done by either base or acid. The problem with offering more suggestions is that you don't show a reaction scheme, so there's no way to tell what dummy acceptor will be most compatible with your chemistry. I also have no references to which to point you. Sorry that's all the help that could be offered.
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I synthesized schiff base from P-anisidine and n,n-dimethylaminobenzaldehyde. But my p-anisidine is not pure. So I want to recrystalize it. So for DNP also. DNP used for another schiff base with vanillin. Thank you
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p-Anisidine turns black due to areal oxidation and even recrystallization using active charcoal too some times no better quality of desirable purity of p-anisidine is obtained. For purification it is best to distill p-anisidine under reduced pressure (avoiding use of water circulation in the condenser) . I have purified p-anisidine many times by distillation under reduced pressure to obtain -anisidine as perfectly white / colorless solid.
DNP (or DNPH) normally is a easily available commercial material. If required it can be purified by recrystallization with MeOH or EtOH using little co-solvents like dicholomethane or benzene (hazardous, to be used with care). But normally it is not necessary to purify DNP itself. For preparation of 2,4-dinitrophenyl hydrazone derivatives, DNP solution (Brady's reagent) is used. To prepare Brady's reagent dissolve commercial DNP (4 gm) in MeOH (85-100 ml) (taken in a dry 250-500 ml beaker) by slow and gradual addition of about 15-20 ml of conc. H2SO4 with stirring (external cooling may be necessary) till DNP dissolves completely and goes into solution (please stop addition of sulphuric acid as soon as DNP dissolves completely). On cooling to room temperature some crystal of DNP salt (light yellow needles) may appear.....filter it or dissolve it with little more MeOH to obtain clear Braddy's reagent. This is sufficienly pure for use.
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In the last step of the synthesis of 1,2,4-triazole from acids hydrazides and isothiocyanates, 1 M HCl must be added to get the final product precipitated, by mistake I used concentrated HCl, the IR spectrum says that the product is the acid from which I synthesized the acid hydrazide (one of the starting material)! is it possible that 1,2,4-triazoles get hydrolyzed in such strong acidic media?
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Can you attach me updated pdf papers in the field of 1,2,4-Triazole complexes
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I am trying to develop Curcumin bioconjugates by esterifying -OH moieties of Curcumin aromatic rings.
By performing UV spectrophotometric analysis of the conjugate (red curve) in a mixture DMSO/H2O, there is an uplifting of the peak in the UV region (between 250-270 nm) and a lowering of the Cur (1,6-heptadiene-3,5-dione) conjugated system peculiar peak at 420-440 nm in the VIS region.
Compared to the behaviour of bare Cur solubilized in pure DMSO (blue curve), where its UV profile is opposed (lower peak in the UV region and a higher peak at ≃ 430nm).
Could the uplifting in the UV region be attributable to an auxochrome effect of phenolic -OH after esterification ? Note: it is noteworthy that the polymer scaffold chosen for the esterification is not UV active, according to the absence of any insaturation within its structure. Thanks in advance to who will give a hand.
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I dont know if Cur properties can remain intact after exposure to the esterification process:
1) I guess that the OH groups can be involved in the UV properties of the molecule with enol-keto tautoremism. So, if you convert one alchol to esther this equilibrium cannot exist, changing the absorption/emission properties of the dye (the same happens with others dyes)
2)This molecule could react also through intramolecular michael adition, yielding another molecule different than the Cur.
Furthermore, you should compare the UV-VIS spectra using the same solvent to be sure that you are assigning the sorption bands properly (pure DMSO or the H2O/DMSO mixture for both compounds)
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I’m trying to synthesize a symmetrical 1,4-dihydropyridine ester compound via Hantzsch reaction with microwave using ethylene glycol as the solvent. A literature said that the compound is a pure oil, and not much information besides that. After 30 minutes of reaction (not complete as monitored by TLC), there is some orange gummy product formed on the base of the round-bottom flask. TLC shows that there are a lot of spots at this point, I’m not sure if they are side products or unreacted intermediates. After extending the reaction time to 60 minutes, I decided to stop the reaction and try to workup the mixture. I’m quite sure that my intended compound is in the gummy product, but TLC of the gummy product still shows a lot of spots similar to the 30 minute TLC. I found that the gum completely dissolves in acetone, DCM, and ethyl acetate, and it is insoluble in water and hexane. Do you have any tips to purify my desired compound from this gummy product? Thanks in advance.
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Hi Samuel,
Have you tried vacuum distillation or recrystallization? And silica gel columns are also a commonly used method for separation.
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I am trying an reaction that convert enol to enol triflate, but I am not sure whether the crude NMR shows reaction is working.
Reaction conditions:
In an ice bath, mixture of S.M(1 eq) and DMAP (0.1eq) dissolve in dry chloroform and dry pyridine (2.1 eq). After stirring few minutes, triflic anhydride (2.1 eq) is added dropwise into the reaction mixture and stir it for overnight.
I would like some advice from experts, thanks! (:
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Alan Lee TLC looks very clean, I'm jealous lol!
Your plan sounds awesome and I hope it checks out.
Have a nice day!
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Nitration of anhydrous Ethanediol is done with Adding 65% Nitric acid with excess 98% sulfuric acid around 100 degrees C (adding one chemical drop by drop on mix of other two, allowing copious fumes of NO2 go out and) and then boiled above 180 C (to remove all yellow-brown color of the liquid to colorless).
The dehydration of ethanediol is likely to produce ethene-1-ol that may be further dehydrated to ethyne (acetylene, and escape from solution) or tautomerized to ethanal (acetaldehyde). Nitrating can produce either 2-nitroethanol or 1.2-dinitroethane, or the nitric acid itself can oxidize acetaldehyde to acetic acid. Or can nitroethene form?
However, I cooled the solution to 4 C and reheated to around 30 C, but fine needle shaped crystals precipitated that didn't dissolve. Is this glacial acetic acid? I cannot separate them due to lack of distillation apparatus or Barium Nitrate.
BTW: I took the supernatent liquid at room temperature, dissolved it 2000 times and drank it a little. It tastes awfully sour, but doesn't taste like vinegar. When I was boiling the solution, upon ceasing of chocking sharp metallic-smelling brown fume evolution, a strong vinegary smell appeared.
As I kept the solution bottled shut for a day or two , some tiny gas bubbles started to appear. What are these bubbles? Acetic anhydride, Acetylene, or something else? they are very low voluminous, so cannot be put to test for gases as per wet-chemical method. And I do not have Gas Chromatography at my hand.
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I would say the reaction forms 1,2-dinitroxyethane, similar to the nitration of glycerin provides 1,2,3-trinitroxypropane (a.k.a. nitroglycerin). 98% Sulfuric acid leads to the protonation of nitric acid, facilitating the nucleophilic attack from an OH group of ethanediol. Do it twice and you get the final product. And as you said, dehydration reactions due to OH protonation can also occur.
But please, stop drinking things (known or unknown) you synthesize in the lab. There are faster ways of dying.
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Hi Everyone,
Just wanted to know more insights about isolating Suzuki–Miyaura Coupling Reaction product. I carried out the reaction in at reflux overnight with THF:H2O=3:1 ratio, K2CO3 as base and Pd(Dppf)Cl2 as catalayst. I have trouble isolating product and would like to know different ways to isolate the product.
Thanks!
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The information provided by you is not sufficient. Can you please elaborate your experimental information? For example, which kind of substrate you have used for cross-coupling, whether you are doing a workup or not, what kind of stationary phase you have used for the purification, etc.
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The m
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Your cyclic peptide also includes a thiazole.
Check
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If I want to synthesize the product shown in the image, would it be faster to use option A as the starting material or option B. My goal is to synthesize the product in the space of 4-5 hours, which is the best option to use? also what reagents should be used for the synthesis? i was thinking of mixing the starting material with dry methanol and then adding TMSCl while the solution is in an ice bath then removing the mixture from the ice bath and stirring till the reaction is complete. the issue I have is that this reaction usually would take much longer to complete. what is the best way to approach this problem?
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Hi, the starting material doesn't matter. I would use the unprotected amino acid (its way more cheaper), add dry methanol and at least 5 eq of TMSCl. Starting with an ice bath and after 30 min stirring raise to 40 °C for 2-3 h. Check the reaction progess via TLC. Good luck.
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asfasfczcz zczczc fsfjkzmnjhsuas asfaihfa asafafa asfafa
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Reactions, which are run for 14 hours, frequently are just sitting on the bench from 6pm to 8am. I would be surprised if it is completed in much shorter time.
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Hello, folks
I am looking for a way to link an aldehyde group (CHO) of a compound with an amine group (NH2) of an amino acid to form an imine (Shiff-base)-containing product. Unfortunately, I could not make it though I tried it by changing many parameters such as pH (2~9), temperature (25~80 C), solvents (DMSO~ethanol), reaction time (3~24 h), and so on...
I have also followed some recipes in the references regarding the reaction, but it was not so successful at this time.
Are there any one who is experienced in this experiment and what kind of solution would it be possible? Your kind advise would be pretty much appreciated !
Best Regards,
JH.
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You could use some acids such as PPTS, PTSA, PhB(OH)2 to activate the aldehyde. Other way is to heat the reaction mixture while removing the water that’s being formed using a Dean-Stark apparatus, you’ll need to heat it in toluene.
imine formation is a reversible process so consider the removal of water by any mean posible.
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Hi guys,
I'm dealing with the synthesis of 1,1,2,2-tetrakis(4-aminophenyl)ethene follows the method in the reported paper. In which they used tin powder and concentrated HCl as reagents.
But I only obtained very low yield of desired product, the crude NMR shows the conversion was only 26%. I wonder if there is a procedure to activate Tin powder before using it in reaction?
Please check the attached for the original paper.
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Dear Van-Sieu Luc, I have performed many McMurry Reactions however we used actvated Zn dust to reduce TiCl4 to Ti(0). Prior to reaction, we have purified commercial Zn dust as follows: Zn dust was quickly washed with distilled water containing few drops of conc. HCl (0.5-1% HCl can be used/ I think it's in Vogel's Practical Organic Chemistry book) to remove the oxide coatings in any. Then thoroughly washed with distilled water to make acid free and finally with acetone and dried under vaccum. It can be stored. This Zn dust can be used for reduction of TiCl4 to Ti (0) in anhydrous dimethoxymethane solvent under reflux under inert atmosphere for 4-5 hours. We used 0.025 gm atom of Zinc for reduction of 0.0126 moles of TiCl4 and this insitu generated Ti(0) was used for McMurry coupling of 0.003 mole of beta chloro-alpha,beta-unsaturated aldehydes. Yields varied in between 50-92 %. You are welcome to go through the paper "STEREOSELECTIVE SYNTHESIS OF 1,6-DICHLORO-1,3,5-HEXATRIENE DERIVATIVES BY MCMURRY COUPLING
OF beta-CHLOROACRYLALDEHYDE DERIVATIVES" Susmita Gupta, Gandhi K. Kar and Jayanta K. Ray, SYNTHETIC COMMUNICATIONS, 30( 13), 2393-2399 (2000).
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Working with these two reducing agent since a long time just wanted to know the advantage of one over another.
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Dear Siddhant Singh, in order to get an answer compare their 'standard reduction potential'. Please have a look at the following video. My Regards
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I have been trying to reduce the chemical above and have run into issues. When the product is formed, it is not volatile enough to boil out.
These methods below I have tried:
- Sn/MeOH + HCl
- SnCl2/EtOH
- Zn/AcOH
I am under the impression I can do a steam distillation, but the bp of the product is 238 degC. If anyone has any literature or advice on this, it would be greatly appreciated.
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Aniketh, This is not true. Chlorine is strongly accepted to the benzene ring.
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I recently purchased 3 bottles of dimethyl acetylenedicarboxylate from Sigma-Aldrich and decided to check the purity of the product using TLC. I found out that the chromatogram actually showed 2 spots, Rf 0.1 and 0.8. I believe the bottom spot is due to the decomposed product since it's the minor compound of the mixture. Any idea what this could be?
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I have the same problem as you
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I am doing the synthesis of tert-butyl 6-(3-hydroxy-propyl-methy-lamino)quinoline-4-carboxylate, using Cesium carbonate, BINAP, and Pd2(dba)3 and N-methyl-1,3-propanolamine in Toulene.
TLC using different solvents and ratios didn't work out even using column chromatography, so does anyone know how to purify my compound ?
to get rid of Cesium Carbonate, BINAP and Pd2dba3 ?
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Thanks a lot @Vladimir Khlebnikov
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How to remove N- methyl morpholine from the coupling reaction for getting a pure compound?
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I am wondering if anyone has any insight as to the reactivity of malonyl dichloride in the presence of pyridine and mono-boc-protected phenylenediamine? I start the synthesis with the boc-protected amine and pyridine in a dry THF solution. a diluted solution of malonyl dichloride is then added drop-wise ca. 1 drop/sec over 40 min. As soon as I start adding the malonyl dichloride, the solution starts turning pink. If the solution is left over 2 days at RT, it turns blue. I tried to adjust the temp (-20degC), time (30 min and monitor by TLC), but, somehow, it keeps turning pink/dark red.
If the reaction is replicated with dimethyl malonyl dichloride, no pink solution is observed, and the reaction proceeds towards products, with high yields.
Does anyone have experience with malonyl dichloride?
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The difference between malonyl and 2,2-dimethylmalonyl dichlorides is that the former possesses hydrogens in the alfa position to the carbonyl group. What often happens with acyl chlorides of this sort in the presence of bases is the formation of ketenes by abstraction of HCl by the base. The stronger the base, the greater the extent. ketenes are capable of acylation, but prone to the formation of other products. Phenylenediamine, even with Boc-protection is not an easy compound either. You judgement was quite correct when you were adding the dichloride dropwise at -20oC. Pyridine as a base is a good choice, too. It is likely that you generated a good yield of the desired malonyl diamide, but some colored impurities are hardly avoidable when you have an acyl chloride as reactive as the one you use. If these impurities are critical or the yield is too low, you may wish to react malonyl dichloride with N-hydroxysuccinimide. Once bis(N-oxysuccinimidyl) malonate, a much milder acylation agent, is formed in situ, it can be reacted with mono-Boc phenylenediamine. Good luck with your chemistry!
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In the structure of many drugs, there is a carboxylic group
What is the significance of this group? Why should it exist in the structure of a drug?
Do you know any article or book or reference about this subject?
Thanks a lot
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Nalidixic acid - A NSAID grs of drugs or pain killer .REF : en.wikipedia.org ( Image Source ) .
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Is there any free website or software for checking physical/chemical properties of organic compounds or published papers by structure search?
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Dear Malar vizhi J.M functional groups in 2-bromo-4,5-dimethoxycinnamic acid are principally all substituents other than hydrogen atoms. First you have the bromo substituents, which can be substituted by other moieties. Other functional groups are the two methoxy (–OMe) groups and the carboxylic acid (–COOH) functional group. Finally, the -CH=CH- double bond can also be seen as a functional group as you can do derivative chemistry with it (such as adding Br2). I hope this answers your question. Good luck with your work and best wishes, Frank Edelmann
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In my job I work with bent-core molecules, which have many aromatic rings with ester and biphenyl groups. And I use a benzylic group as a protecting group for one aromatic OH.
In the literature, the deprotection of this group to an OH takes place overnight. However, I require heating up to 50 °C or leaving the reaction for at least 3 days.
Why could this be?
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1. You must use high hydrogen pressure on a large scale of starting material (2g or more) for rapid hydrogenolysis.
2. Try working with a wet 50% Pd/C, dry Pd/C often fails.
3. An alternative method is to use lewis acids (FeCl3, TiCl4)
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Dear RG Community,
quinalizarin is a dye that used to be very common. Unfortunately, it is hardly used today and, as far as I know, can only be purchased in small quantities at very high prices from Sigma Aldrich:
A BASF synthesis route (according to Bohn) uses the hydroxylation of alizarin with oleum. However, we could not find a detailed synthesis protocol for this.
We would like to use quinalizarin for educational purposes of our students to detect Mg2+ and Al3+ as lake pigments. Of course, we are aware of other methods and reagents, but would like to try this particular option.
My question is therefore, if someone knows a source of purchase quinalizarin or if a group still has stocks from which they could help us with a small amount.
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Dear Florian and Chen Jingwen unfortunately Alfa Chemistry does not sell quinalizarin either. When you check their website for the term "quinalizarin" you receive a message saying that the product is currently not available (please see attached screenshot).
With best wishes, Frank Edelmann
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Could anyone provide a details on separating allene from alkynes in the mixture of allene and alkyne?
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Dear Sarah Rabbitt the boiling points of propiolic acid and pyruvic acid are 21 deg. apart. Thus it should be possible to separate the two acids by careful distillation though a Vigreux column. In case that this issue is still of interest to you, I think you should not hesitate to ask this as a separate technical question on RG. Good luck with your work!
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I extracted the essential oil and I found that my major compound represent 95 % of the mixture and only less than 5 % as minor constituents ( 20 constituents).
I'm I allowed to take my major constituent as starting material to perform chemical reactions?
Do the minor constituents representing only 5 % will not disturb the obtention of the desired compound?
I would like to insert some functional groups to increase bioactivity.
Any help in this regard will be appreciated.
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Dear Alexander Sinko, well done ! 95% !!!, as dear Dr Erdal mentioned , I advise you to be careful to remained 5% ( 20 components), you can use Column Chromatography or Solvent extraction........
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What kind of functional groups do we need to insert by the synthesis in organic chemistry to have anti-cancer activity in perspective?
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Consider two small molecule anti-cancer drugs, Enasidenib and Ivosidenib, which are IDH1/2 inhibitors approved for AML treatment. The fluoride moieties are a prominent feature. If you remove them from the molecules, their PK will be completely messed up; in fact, without the fluorines, they will most likely vanish like the clappers once they reach the liver, due to rapid metabolic degradation. Another distinguishing feature is the predominance of six-member aromatic rings and amide/amine linkages. A drug must be reasonably soluble in water and capable of being transported through the bloodstream to be effective when taken orally. Because amines are weak bases, they are frequently converted to salts with some acid, and thus some oral drugs contain amine salts. One reason for their presence is that they provide the drug with some water solubility. Scientists have taken a cue from nature by utilising the versatility of the amide group. The amide chemical group reigns supreme in medicinal chemistry. The group features in almost all of the bestselling drugs. Because amides have the right amount of stability and polarity, they can interact with biological receptors and enzymes. Because drug design is so nuanced and cancers are so variable, determining which functional groups should be inserted into a drug to boost anticancer activity is best left to experience, modeling software, and repeated tests.
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I want to start from phenol to synthesize this compound, but I dont know about the detailed mechanisms and conditions.
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Dear Jialiang,
many thanks for sharing this very interesting technical question with other RG members. I did a SciFinder search for this compound and found that it is not known from the previous chemical literature. However, the analogous compound is known in which the ethyl group in para-position of the phenyl ring on the left side is replaced by a methyl group. This compound has been reported in the following article:
Chemoselectivity in the Cu-catalyzed O-arylation of phenols and aliphatic alcohols
Fortunately this paper has been posted by the authors a public full text on RG. Thus you can freely download it as pdf file and print it out if required. The synthetic route is outlined in the attached reaction equation. You just need to replace the starting material 4-iodotoluene by 4-iodoethylbenzene.
Good luck with your reserach work and best wishes, Frank Edelmann
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I have a dowex column in H+ form and I want to exchange it with tetrabutylammonium form. What concentration of tetrabutylammonium hydroxide do I need to prepare to pass through the dowex column? What other steps do I need to take?
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Hey. Its been so long, I can't remember if I got the result that I needed or not.
You could call the company that manufactures the Dowex columns and ask for assistance. They might be able to guide you in the right direction. Good luck.
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I've been trying to prepare polyimine based polymer in DCM/DMF/TOL solvent system.
First I let aromatic di-aldehyde reacted with di-amine with long carbon chains (4-6 carbons), as soft segments. After some time, I introduced aromatic di-amine, the hard segments, as chain extender, then the solvent became very turbid, showing that the solubility is not good.
Later I found the turbid solution can only be solubilized by AcOH.
The hard segment is very important to my project and I can't replace it, and the weight% is quite low already.
I was thinking if I could prepare the polymer all over but in pure HOAc, or high weight% of HOAc?
All my solvents are non-aqueous, or only trace of water coming from the formation of imine.
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Dear Bryan,
thank you for posting this interesting question on RG. As an inorganic chemist I'm not a specialist in polymer chemistry enough to give you a qualified answer. In this context I keep wondering about two things: Why are you expecting a soluble polymer when you use aromatic units as hard segments? And why do you want to work in nasty acetic acid when "normal" organic solvents will also work? To the best of my knowledge the formation of low-molecular weight Schiff bases from aldehydes and amines is often catalyzed by small amounts of acetic acid. Thus I assume that a few drops / ml of acetic acid will do in your case too. For some potentially useful information please have a look at the following relevant articles in which the formation of polyimines in various organic solvents has been studied:
Tuning the physical properties of malleable and recyclable polyimine thermosets: the effect of solvent and monomer concentration
and
Synthesis of imine bond containing insoluble polymeric ligand and its transition metal complexes, structural characterization and catalytic activity on esterification reaction
The first article is freely available as public full text on RG, while the second one is not. However, five of the authors have RG profiles, so that you can easily request the full text from one of them directly via RG (provided that it is of interest to you).
In any case I wish you good luck with your research work!
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I am performing an esterification reaction using "A with -acid chloride + B with alcohol" to get "A - Ester - B". This reaction uses Pyridine to trap HCl gas as Pyridinium Hydrochloride, so that we can easily remove the impurities. Other than Pyridine, is there any reagents I can use which are non-toxic.
(I already reject Triethyl amine, and DMAP).
Any advise in this regard is highly valued.
Thanks.
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Try with triethylamune.
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I am trying to do quaternization of acridine dye at 100 deg. Celsius under solvent free conditions and in a nitrogen atmosphere. After I added the DMS, it started to boil at 100 deg. Celsius and formed droplets on RBF walls and the reaction did not complete. The actual boiling point for DMS is 180 deg. Celsius.
I don't understand what is happening in the reaction? I have worried about the purity of the DMS. Although I added excess of DMS, the reaction is not completing. Please help me to solve this issue.
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You can check the amine value while adding DMS at different times. Once amine value becomes zero or less than 5, you can stop the reaction or addition of DMS.
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In literature, it is reported that barbituric acid is soluble in water, however, it appears to have solubility issues and as such it does not dissolve completely in water or alcohol.
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Barbituric acid slighltly soluble in water. So, you can wash the reaction mixture with NaHCO3 solution after completion. it may remove the unreacted barbituric acid.
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How can/should we distinguish between a Biochemical and a Chemical Reaction.
As per one explanation:-
Chemical reactions are discrete reactions with catalyst involved in the process where as in biochemical reactions there are a series of reactions involved with the product of one acting as the substrate for another and this complex process of interchanges taking place with the involvement of enzymes.
For a more specific example if we are conducting photosynthesis in vitro then it will be considered as a biochemical reaction rather than a chemical reaction.
But the dilemma stems from the fact that, even chemical reactions go through complex series of steps, like any organic synthesis reaction. In this case also there is the involvement of catalysts like enzymes. Thus, can we consider it as a biochemical reaction! But mostly we only attribute it to be a chemical reaction which is indeed the case.
So, what is the proper difference or point of distinction between a biochemical and a chemical reaction. How can we exactly relate that one reaction is a biochemical and the other is chemical!
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Dear @Mrutyunjaya Panda All biochemical reactions are chemical reactions. I agree with Dr @Frank T. Edelmann in that in principle, there is no major difference. The same reaction can occur 'in vivo' and 'ex vivo'. You can also access a similar discussion at the following link:
Best wishes, AKC
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In reaction of isocyanate or isothiocyanate with compound containing aromatic amino and hydrazine group, how to improve reaction selectivity toward hydrazine group only?
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Dear Mohamed H. Aboutaleb many thanks for your interesting question. Unfortunately the question is a bit too general in nature to give you a qualified answer. In this point I fully agree with Vladimir Khlebnikov in that it would be helpful if you could specify you aromatic amine / hydrazine precursor in some more detail. If I knew a structural formula I could easily do a SciFinder search for you to find out if reactions with isocyanates or isothiocyanate have already been reported.
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Trying to improve a process I have been given. The chloro analogue is far more readily available and I would prefer to use that to couple with my acetylene.
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The palladium(II) complex is an effective catalyst for the coupling reactions of aryl Chloroaromatics.
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I want to remove the solvents from my product in acid and base medium. If I use the rota evaporator it means the pump gets affected. Is there any solution for this problem?
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The best method of removing solvents like chloroform, THF, dichloromethane without using a rotary evaporator is simple distillation on water bath.
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The simple polymer tests in that image incited these questions to me-
  • Why would red-hot copper wire burns with Green flame when polyvinyl chloride (PVC) is burnt on it but orange flame in case of polystyrene (PS) and polyethylene terephthalate (PET)? Is the HCl generated from burning PVC generates Cu(II) compounds upon reacting with copper in case of PVC, but not in case of PS or PET? But doesn't Hydrogen have higher reduction potential than Copper (EMF series), and copper may anyways oxidize in air at high temperature to provide a green-blue flame?
  • Why acetone reacts with PS but not PET? Acetone's (propanone) central C atom is not as much electropositive as methanal (formaldehyde), but still it can undergo nucleophilic addition. But while one alkyl group (ortho-para substituent) enhances electrophilic substitution reaction tendency in case of benzene ring of styrene in PS, two carboxylic groups in terephthalate causes benzene ring to be deactivated for electrophilic substitution in PET. Is this reasoning okay or is there anything wrong with it?
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One side is looking at density - whether it sinks or floats in liquids of different densities - water, alcohol, etc. Geologists do this with minerals - but they use bromoform (2.6 g/mL)!
the other side is using chemistry and solubility - flame tests to show presence of chlorine in PVC, what solvents different polymers dissolve in.
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I just made a small molecular compound comprising of both amine and hydroximic acid groups, after I quenched and neutralized the reaction, I directly freeze-dried the mixture and then dissolved the solid in acetonitrile and water (1:1) solvent for HPLC. The mixture just separated into two layers after the full dissolution. I think it is a little odd as the ACN is miscible with water and I cannot do HPLC if the mixture has two layers, so what should I do.
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1.You can change solvent methanol Water
2.also use buffer.
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Hi everyone,
I am a teacher of Heterocycles Synthesis,
Is there a home practice that you recommend for undergraduate students? A simulator would also be useful
Due to the pandemic, students only have materials that they can buy in the market.
Regards,
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Dear Reyna Martha Gallegos Alvarado here is another interesting heterocycle synthesis experiment designed for undergraduate students.
One-pot green synthesis of dihydropyran heterocycles
"This experiment aims provide the students with the knowledge about the One-Pot synthesis of dihydropyrans."
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I have produced oleum by adding sulfur trioxide, SO3, to sulfuric acid. It mostly contains disulfuric acid (also called pyrosulfuric acid) but i think this method is not suitable for laboratory purpose so is there any feasible procedure for the synthesis of oleum for laboratory purpose?
Suggestions will be highly appreciable.
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Dear Daniyal Ahmed just in case that this question is still of interest to you: The article cited below contains a detailed description of how to make oleum in the laboratory:
Preparation of Sulfur Trioxide and Oleum
Personally I would suggest to buy oleum from commercial sources as it is an industrial product manufactured on a large scale.
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Can anyone recommend some any software/models available that can predict substance reactivities and the reaction yield under a specific set of reaction conditions process and proposing pathways to synthesize target molecules from a complex mixture?
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Dear Talal Ashraf there are two potentially useful article on this topic available as public full texts right here on RG:
1. Predicting Feasible Organic Reaction Pathways Using Heuristically Aided Quantum Chemistry
2. Neural networks for the prediction organic chemistry reactions
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Hey all,
I wanted to gather expert input on the stability of dimethylformamide under basic conditions at reflux:
I want to reproduce the results of Michael G. Bell et al. in his patent
"Preparation of 3-phenylisoxazole derivatives for treatment of dyslipidemia
By Bell, Michael Gregory et alFrom PCT Int. Appl., 2007092751, 16 Aug 2007 "
They claim that the condensation reaction of 2-fluorobenzaldehyde with mercaptoacetic acid in refluxing DMF with KOH as base proceeds smoothly and with a yield of 78%.
EDIT: The product of said reaction is benzo[b]thiophene-2-carboxylic acid.
On the other hand it's been reported that KOH as a strong base readily catalyzes the decomposition of DMF to dimethylamine and potassium formate (presumably), as can be read in the EROS article ( ).
Now I want to ask you guys whether you've worked under these conditions before and whether you've experienced a disastrous decomposition of solvent or a pleasant reaction with pure products :)
Best regards
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DMF is poorly stable in aqueous alcaline solution. When we deal with concentrated alcali (say KOH over 20%) and temperatures over 50-60 deg, DMF will be completely unstable, it hydrolyses immediately, in seconds (NOTE!).
Meanwhile, this allows to construct very convenient laboratory device for generation of permanently strong stream of dimethylamine gas -
just add dropwise DMF to hot (80-90 deg) stirred solution of about 30-40% KOH, you will get up to 2 moles/hour stream of dimethylamine and this device could work for hours, requiring only minor control.
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SPPS of a 16 aa peptide was performed on a 0.15 mmol scale. Resin gained a minimal amount of weight: starting weight of 224 mg and a final weight of 280.I believe my peptide failed to elongate but im not sure why.
Rink amide MBHA resin was swollen, deprotected by 20% Piperidine/DMF prior to addition of an Fmoc protected Diaminobenzoic acid linker (Fmoc-Dbz; Peptide Intl). After coupling of Fmoc-Dbz for 40 min, a Kaiser test indicates a 99.8% coupling yield. I proceeded with the synthesis and ended with a standard Dbz --> Nbz derivitization (acylation of Dbz with p-nitrochloroformate, followed by base-catalyzed cyclization; Dawson 2008).
Ive performed many synthesis and have never failed to elongate. I will attempt to cleave the product soon and analyze by LCMS but I need to wait through the holiday. Does anyone have any experience with this sort of failed synthesis?
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Hi i agree with Saraniya Bharathi Based individual amino acid combination - the peptide validated as "Easy" "Hard" to synthesis.
You may synthesized many peptides but this was failed due to sequence difficult - if you provide sequence means i will validate it and give you clear reply.
Some Points :
1. You used Rink amide resin - so here there was no problem found
2. After first amino acid coupling - amino acids solvation effect and coupling deficiency issues synthesis goes to wrong direction .
3. Each amino acids have different internal properties - Neutral and Hydrophobic amino acids create trouble - so before planning to synthesis - you write protocol for each "Hard" amino acid.
If sequence easy means no issues - if "difficult sequences" means should be careful and modify your procedure in difficult red-zone area of the sequence.
Hope some of my publications have details about this - may helpful for your research.
All The Best For Your Research and Success
- Dr.R.Selvam - Custom Peptide Synthesis Expert
Grey Matter Research Foundation.
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I found only one procedure where they use CaH2, is CaH2 safe to be used with BF3?
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Unlike other halides of boron BF3 doesn't undergo hydrolysis. BF3-2H2O is a very stable compound. So BF3 etherate is also hygroscopic and you need to dry it before using it with any sensitive reagent. I dried it using CaH2 and distilled under reduced pressure. It's better to filter off CaH2 and the solid residue if you don't want to distill under vacuum. I also came across someone using P2O5.
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I tried several routs suggested in literature to perform coupling reaction between acid and amine at the Au surface using EDC-NHS in water but was not successful. Could you please suggest any better way to do this?
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I think you can use DCC for better result 📷
For other approachable method you can go to those link where you can find various method of successful bioconjugation
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Is there any effective method to reduce oxidation effect of nitrous acid (HNO2)
as it is converting my diazo compound into tars while diazotizing it,affecting the results of my final product.
Below attachment is my diazo compound.
Suggestions will be highly appreciated.
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Lignosulfonate is an insoluble biopolymer in the organic solvents. How we can dissolve this polymer in an organic solvent?
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and who told you that LS are not soluble in organic solvents. Try it first.
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How can I remove excess amine from these reaction products? I did the reaction which may formed mono and di adduct and also present some excess amine.
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You can prepare a mono adduct of amide from the reaction between lactone and ethylenediamine by heating one mole of lactone with half mole of ethylene diamine in ethanolic solution.
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Is there any possibility of nucleophilic aromatic substitution of hydroxyl group directly without the presence of sulfonic group etc ???
kindly suggest me??
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There no possibility of nucleophilic aromatic substitution of hydroxyl group without the presence of sulfonic group as OH is not a better leaving group.
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I am using chlorosulfonic acid in chloroform (inert, 2 hr, RT) to para-sulfonate benzyl groups on a dibenzyl ether. The work up is extraction with water. The reaction, however, does not seem to work. Are there other reaction conditions and/or work up to try for aromatic sulfonation reaction?
I have tried an alternative, stirring with sulfuric acid for a few days, however, I cannot obtain pure product without large amounts of inorganic salts.
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agree with Kurt Wachholder
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According to the fact that we couldn't use huge sonicators and run the same lab based experiment for industrial productions because of its acute or chronic health effects, I wonder what is the best replacement for sonication to obtain a homogenous mixture of polymers and nanosheets in industries?
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Dear all, what is the role of sonication in your case? Is it for mixing/dispersion or for reaction assisting. If it is for the later option you can use microwaves. My Regards
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Etherification was carried out between aromatic -OH group and alkyl chloride in the presence of ethanolic KOH. The precursor is a bulky dye compound that consists of an aromatic -OH group and an ester group.
When the reaction stopped, I tried to remove the excess KOH by extraction. The product can only extracted by ethyl acetate (cannot be extracted by DCM, CHCl3, diethyl ether, toluene). However, strong acetic acid smell was detected in the extracted layer after the solvent was evaporated.
I tried to directly recrystallized the product in ethanol after the reaction, no crystal was formed but an oily layer emerged beneath the ethanol.
Is there any suggestion to remove these KOH and unwanted inorganic by-product after etherification?
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To remove the KOH from ethanolic etherification without using extraction method , neutralize the reaction mixture obtained after reflection by treating with 2N HCl to PH=7 , organic layer separates out.Extract organic layer with chloroform or dichloromethane. Removal of Organic layer under vacuum will give ether.
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In Homoleptic iridium based complex synthesis. in second step of reaction the glycerol used as solvent. after the reaction the reaction mixture added to water. at extraction time the glycerol is completely not extracted. and not forming a solid. is there any way to remove glycerol and get solid. 
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To remove glycerol from the reaction mixture give gentle washing of methanol, so that glycerol becomes soluble in it and dry product separates out.
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I'm working on gelatin modification. To do this, the amine group was protected by BOC and the carboxylic group was activated by EDAC and NHS to form a stable amide bonds with another amino-content small molecule.
Now I need to remove the protecting group. As in the reference, they use the conc. HCl (0.5 % v/v to sample) at 4 degree Celsius to deprotect the BOC. But this spend about 2 weeks to reach the full deprotection.
I hope to fasten this process, I have found some papers such as using conc. HCl (0. 01% v/v) at 40 degree celsius take about 16 hours and HCl (4M)/dioxane at 0 degree celsius take around 30 mins for deprotection. Will these methods also break the amide bond of gelatin and the additional group that I'm grafting to the backbone? Anyone has experienced in this kind of reaction, please help !!!!
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You may try 0.1 N HCl in hexafluoroisopropanol or trifluoroethanol.
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Hi, can anybody suggest me a single step ortho carboxylation of methoxybenzene derivatives. What are the best sets of reagents
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In addition to the answers afforded by Frank T. Edelmann and Abdelkader BOUAZIZ , I suggest another synthetic way. This includes the formylation of anisole using Vilsmeier–Haack reaction and the product is then oxidized to form the target product.
All the best
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I am working on research. I would like to connect a conjugated aldehyde (like citral) to another ketone compound at the carbon alpha to the latter's carbonyl group. I tried to use Mukaiyama aldol reaction. I generated an enol silane from this ketone compound and then reacted with a conjugated aldehyde, but it failed. I guess that the relatively high stability of the conjugation system from conjugated aldehyde may be a reason. Can anyone suggest me another way to do the job?
I intend to do double alkylation at that carbon position and I would like to preserve an -OH or C=O group at the beta position with respect to the C=O group on the reactant conjugated aldehyde.
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Dear Alan
Can you please attached the proposed synthetic scheme to clarify your question and point my answer?
Regards
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Hello All,
I tried to protect the free thiol group using 4-methoxybenzyl chloride via SN2 reaction, but I was not able to do so. I am wondering if you have any suggestions on how to proceed this reaction or on any alternative pathway to protect the S-H group? Thanks :)
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To protect thiol group convert it into thioether by reacting it with alkyl halide in acetone in presence of anhydrous base as potasiummcarbonate
… Read more
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Does the ester bond in my compound breaks If I proceeded a Sonogashira coupling reaction to react my compound (R-O-CO-Ar-Br) with the alkyne derivative?
The reaction condition I'm using:
Bis(triphenylphosphine)palladium(II); DME; TEA; CuI; 200 C; 24h
Thanks!!
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You might have cleavage of the ester depending on the base you use, but most bases traditionally employed in Sonogashira couplings should be safe.
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I am trying to synthesize a compound which has both carboxylic acid and amine. During the purification, when I do the pH adjustment it forms a zwitterion and goes into the aqueous layer. Is there a way to desalt such compounds?
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Crystallization of a zwitterion at the isoelectric point is tricky and often inefficient. If you only need a small amount of product and high yield is not the goal, AND you have a good estimate of pI, this can be the quickest way to get what you need. If you are doing this preparatively and/or if the compound does not crystallize well from your original mixture, ion exchange resins will probably be the most effective tools. (If you are trying to recover your product from a complex mixture, you will need to do IEX chromatography; please provide more details.)
When amino acid zwitterions are being synthesized, cation exchange resins such as Dowex 50, Amberlite IRC120 and others offer a very simple and efficient method for recovering products. The following process is frequently used following acid treatment, such as amino acid amide hydrolysis in HCl(aq):
RCH(NH[R'C=O])CO2H + xs HCl(aq) --> RCH(CO2H)NH3+ . Cl- + R'CO2H
The hydrolysis mixture consists of RCH(CO2H)NH3+ . Cl-, R'CO2H, water and excess HCl (e.g. R'=CH3 for an amino acid acetamide, where acetic acid is a volatile byproduct).
1) Evaporate excess volatile acid (rotary evaporation will remove water and HCl gas.) Purging HCl gas in a stream of N2(g) beforehand (fume hood) will reduce bumping during evaporation. Vent the vacuum pump exhaust to fume hood.
2) Dissolve the acid evaporation residue in a small volume of water
3) Calculate the number of millimoles of the zwitterionic substance you intend to isolate and pack a short column with 2-5 times this number of milli-equivalents of appropriately-washed NH4-form ion exchange resin (preparation usually done by washing with strong acid solution followed by water to give neutral eluate, then aqueous ammonia treatment to convert RSO3H groups to RSO3- .NH4+, and finally thorough washing with deionized water to give neutral filtrate.)
4) Slowly apply the solution of evaporated hydrolysis mixture residue onto the column, then wash the column with pure water until the eluate is free of Cl- (AgNO3 test) and the pH is neutral (or not lower than the pH of your DI water). At this point, the acidified zwitterion should be completely bound to the resin [RCH(CO2H)NH3+ . resin-SO3-]. (Check the column application eluate to be sure nothing has leaked through. TLC with ninhydrin detection works well for amino acids). You may also check dried drops of eluate with ninhydrin to be sure that displaced NH4+ ion is no longer eluting from the column.
Elute the washed column with aqueous NH4OH, using approximately twice the number of millimoles as meq of resin (e.g a column containing 50 mL of 0.8 meq/mL resin would be eluted with 2 x 50 x 0.8 = 80 mmol of NH4OH(aq), say 40 mL of 2 M). If the product has not completely eluted from the column by this time, more water should be used before you add more ammonia. Very hydrophobic amino acids may elute better if some methanol or ethanol is added to the water.
5) Evaporate the ammonia eluate. As with the HCl solution in step 1, this solution may behave better during rotary evaporation if you first bubble a stream of N2 gas into the eluate to purge excess NH3 (fume hood), followed by vacuum evaporation, only heating once all free ammonia is gone. Nearly all ammonium carboxylate salts (RCO2- . NH4+) decompose upon evaporation with heating to carboxylic acids, so this step is basically:
[RCH(CO2-)NH2 .NH4+](aq) --> RCH(CO2-)NH3+(s) + NH3(g)
i.e. once ammonia gas leaves, this residue is theoretically pure zwitterion.
6) At this point the purification method of choice is usually recrystallization, commonly from water-alcohol mixtures.
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I have synthesized a carbazole-linked donor-acceptor molecule. The 3 position of carbazole is still free. Can I introduce aldehyde group there?
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Formylation: Vilsmeier-Hack Reaction -> Formylation at C3
it is conspicious, that the presenec of an electron- withdrawing substituent at nitrogen directs electrophilic substituition to C2
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What is the most feasible method to synthesise benzoxazole from aminophenol?
i had tried with carboxylic acid derivative in the presence of PPA as a solvent,
but i am looking for some more feasible procedures and methods??
Suggestions would be appreciated.
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Synthesis of benzoxazole can be achieved by heating o-aminophenol with carboxylic acid in presence of polyphosphoric acid. In another method o-amino phenol is heated with HC(OCH3)3 in presence of HCl.
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Hello there, need some ideas and conditions for pyrrolidone cleavage with formation of double bond (C=C) , for now i know that in strong acid conditions (HCl) this group is stable and cleavage do not occurs. Anyone have experience in cleavage this type compounds or seen some papers about this?
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interesting answers
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Role of solvent.
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Dear Gagandeep Kaur,
Polarity of solvent can also have a big influence on the products obtained in organic photochemistry. For example, in the case of photoinduced hydrogen transfer. Two mechanisms are possible : a one-step mechanism where the electron and the proton are transferred in the same time and a two-steps mechanism where electron in transferred first and proton follows. These two mechanisms cannot be distinguished in terms of energy, they are both exergonic. But, for a one-step process, the electron transfer is endergonic where as in the case of a two-steps process, the electron transfer is exergonic. As you could see in our publications (10.1039/C9NJ03061A, 10.1002/chem.200903045), different products can be obtained with different solvent (cage effect discussion is made in the former). $\Delta G^{0}_{el}$, electron transfer exergonicity, is available from the Rehm-Weller equation, as a function of polarity of solvent. For a less thermodynamic point of view and a more kinetic point of view, I suggest you to see this last publication in Science for concerted proton-electron transfer :
10.1126/science.aaw4675.
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Tin in HCl
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The best reagent for the reduction of NO2 group to NH2 group is heterogeneous catalytic reduction using H2/Pt in acetic acid.
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Hi,
I synthesize stannane compound using bromo octylthiophene, n-BuLi and Bu3SnCl. The reaction seems to go well in lithiation step (checking by TLC), but after adding Bu3SnCl,nothing change. I have check NMR for final product but it's octyl thiophene. I doubt that I have problem with my Bu3SnCl because I have opened it for one year.
Could you share your experience if the problem comes from Bu3SnCl and how to treat it to reuse?
Thank you!
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There is a common precautions to consider when it comes to storing conditions and storage time for the chemicals to preserve their initial structure. Such substances can be decomposed with the effect of light and heat. Also if you open them without the right provision ,the material can be subjected to air. Such substances can react with oxygen and water moisture.
You have to keep such materials sealed under the proper storage conditions till their use.
The other thing is that their recovery can be very difficult to you.
So, i would advice you to use fresh chemicals for your experiment.
For sure the cause of the failure of the experiment is the expired Bu3SnCl .
Best wishes
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Chloride salts of following organic bases are commercially available. How can I get their anhydrous hydroxide form?
N,N-dimethylamine, N,N,N-trimethylamine, Guanidine, N-mrthylguanidine and N,N-dimethylguanidine
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I am starting to synthesis my first batch of MOF materials and after a literature review, I often found that the amount of the metal precursor is always higher than that of the organic ligand as required stoichiometrically. Is there any reason behind this?
For example: For the synthesis of Cu3HHTP2 MOF, the stochimetric ratio Cu:HHTP is 3:2 and in literature I found the real ratio used is 2:1 (powder synthesis) and even 10:1 (thin film synthesis).
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In general:
MOFs are "bulk" materials, usually contain more than one ion-pairs and not "isolated" ions/ion pairs unlike in a real solution. That means, on the nanometer scale the particles considerably fewer ions on the surface than the total number. And so, the ligand exchange is restricted to the surface. Additionally, not all the surface ligands can be exchanged.
An example (because I am not an expert of Cu3HHTP2, but I assume that it is general): rutile builds up tetragonal unit cells, where the unit cell dimensions are a = b = 0.458 nm, and c = 0.295 nm. The Ti2+ ions are surrounded by 6 oxygen atoms, forming an octahedron, and the unit cell contains more than one TiO2. Not to say anything about the intercalated other ions.
That means, > 1 nm particle sizes contain fewer replaceable, in the case of rutile the unit cell contains (as average, as Axel wrote) 5 TiO2 while on the surface (of the unit cell) only 8 (of 10) Oxygen is active. In theory on a ~1x1x1 nm particle, while the number of constituting TiO2 is 30, the number of surface O is only 20 (of 60). And usually, the nanoparticles are larger than 1 nm.
Of course, in (theoretical) two-dimensional cases the numbers are different.
Additionally, multidentate ligands further reduce potential substitution sites. So, the mentioned 2:1
Finally, Balakrishna's comment is an inappropriately undervalued comment.
Regarding your example.
There are many missing data, and I assume they are also hidden for you. For the solid synthesis, you mentioned 2:1 ratio. In solid syntheses, there is a size limit, which is generally higher than 1 nm. After that a) I have doubts and the 2D structure might be true only; b) using a 2:1 molar ratio seems to be too low.
Due to solubility issues in solution and lack of yield, isolation method, etc., the 10:1 can be reasonable.
Please, also note that thin films are not necessarily 2D structures, and the reactions are rarely so ideal as they are described in publications - as you are getting more experienced you will see the difference between a publication and real life. Many tricks remain hidden in publications, independently from the journal rank.
So, firstly try to reproduce the published method (=do strictly what is written even if you are not in agreement with the authors!), then, based on your experiments and comparison with the written matters, try to find explanations and understand the authors' synthetic method. This way usually works well. Thinking a lot of unknown things, then to conclude finally to repeat the published method is many times a waste of time.
Good luck,
Laszlo
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I was previously using one of the strong base NaOH in order to convert it into sodium naphtholate (as my compound's physical appearance is in flakes form)
then at the coupling stage with diazonium chloride,
which i assume that my diazonium chloride is reacting at that NaO group (after converting 2-naphthol into sodium naptholate) on the compound.
So, how can i couple my diazonium chloride at the 1st/Alpha/Para Position of the following compound???
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Thankyou Dear Grant Simpson For Sharing This Valuable Information.
I am sure this will be helpful.
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Dear all,
Recently I started collaborating with a chemistry group to synthesize a sugar derivative with isobutyric acid sticking out. The synthesis went well, however the final product has a huge amount of lithium acetate (10:1 Li ac:sugar).
This makes my enzymatic work impossible.
Does anyone know any method by which we could remove LiAc from the solution?
NB:
the compound is soluble in both water and ethanol
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Try using a zeolite resin. It works for removing Sodium in water OR you can try 'reverse osmosis'. Follow was Waters or other water suppliers use.
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When HOCl is added to propene, the product is 1-chloro 2-propanol. However, when the same HOCl adds to allyl alcohol, the expected product is 3-chloropropan-1, 2-diol. But actually, 2-chloropropan-1,3-diol is formed. Why? What is the mechanism of this reaction?
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Could be explained by radical mechanism and allylic resonance. Hydroxyl radical attacks the double bond. Secondary carbon is more stable as a radical so the chlorine attacks carbon no 2.
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Suggestions Required On How Can I Make Below Compound Reactive ?
Basically,I Want To Couple This Compound With The Other (Which Is Highly Reactive).
I Have Tried Converting In Sodium Salt And Dispersing It By Some Dispersants And Solvents But That Doesn't Providing Me The Desirable Results.
Comments And Suggestions Will Be Highly Appreciated.
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I don't think you really need such a strong base as n-BuLi to deprotonate the methylene group in this substrate; bases like NaH of t-BuOK would be sufficient (even K2CO3 in aprotic solvents is used successfully for alkylation of malonates). In this particular case perhaps the electrophile is not reactive enough.
Also, let's not forget that we have an amide NH in a molecule, which is also pretty acidic, perhaps more acidic than methylene. Chances are that you may need to use more than one equivalent of the base. And of course for good results the reaction media should be anhydrous.
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I'm studying the polymerization in solution between a ketone and a secondary amine in function of the pH of the solution. I need some references to study the equilibrium constants of the first hydrolytic step and the second polymerization reaction, in particular I'd like to understand how much intermediate I can aspect and how its presence in solution can affect the reversibility of the reaction.
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