Questions related to Organic Synthesis
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.
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
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.
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
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?
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.
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.
I am trying an reaction that convert enol to enol triflate, but I am not sure whether the crude NMR shows reaction is working.
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! (:
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.
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.
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?
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 !
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.
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
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.
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?
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 ?
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?
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
Is there any free website or software for checking physical/chemical properties of organic compounds or published papers by structure search?
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?
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.
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.
What kind of functional groups do we need to insert by the synthesis in organic chemistry to have anti-cancer activity in perspective?
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.
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.
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.
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.
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!
In reaction of isocyanate or isothiocyanate with compound containing aromatic amino and hydrazine group, how to improve reaction selectivity toward hydrazine group only?
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.
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?
(The image is from http://4.bp.blogspot.com/-aek5e1i0MFA/UB9EYKPXGDI/AAAAAAAAAow/au27uSYHJ3Q/s1600/IDENTIFICATION+OF+POLYMERS.jpg . Cannot post here for copyright issues)
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?
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.
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.
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.
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?
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 :)
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?
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?
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.
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.
Is there any possibility of nucleophilic aromatic substitution of hydroxyl group directly without the presence of sulfonic group etc ???
kindly suggest me??
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.
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?
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?
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.
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 !!!!
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.
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 :)
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
I have synthesized a carbazole-linked donor-acceptor molecule. The 3 position of carbazole is still free. Can I introduce aldehyde group there?
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.
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?
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?
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
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).
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???
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?
the compound is soluble in both water and ethanol
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?
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.
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.