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Synthetic Chemistry - Science topic

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Hi there,
would like to learn more about appropriate material for the application of PPE in Epidemiology.
As all the material seems to be Polyethylene/Polypropylene, would love to learn, whether it is possible to use Polyamide material instead? Are the properties sufficient?
If Polyamide does the job, are normal Snowboarding and Fishing Overalls an alternative to the ordinary Hazmats?
Cherish your feedback.
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The chemical nature of Polyamides, with potential reactive chemical groups, make it more susceptible to contamination than inert PE/PP in an Epidemiology environment. Physical properties are OK.
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Hi,
I am setting up an esterification reaction using EDC/DMAP for R-OH and R'-COOH conjugation in water. However, one of my reactants R' also has an amine (-NH2) group. I am curious as to how the reaction would proceed with EDC and DMAP? And the conjugation would be between R-OH and R'-COOH, and not between R'-COOH and R'-NH2.
Thanks in advance,
Aazam
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First protect the aminogroup. For example with t-BOC group.
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I'm trying to predict the retrosynthesis of an experimental compound from its SMILE string and 3D structure using IBM RXN Chemistry Server. I got some results but not sure about their reliability.
What are the other tools/software/servers available for computational predication of chemical synthesis of a particular compound? Need some methodical answers preferably from an expert of synthetic chemistry.
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The computational predication of chemical synthesis of a particular compound by calculating reactivity index using molecular orbital theory .
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I am looking for a software that can predict the chemical reactions that will occur when I mix certain substances. For Example: Na+Cl --> NaCl.
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Some software of quantum mechanics such as Gaussian, Hyperchem, Material Studio, Gamess, and so on could support you to solve well it. Have a good day!!!
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Respected Sir/Madam,
I've attached a picture of manually drawn organic compound using "Pubchem Sketcher". I was planning to synthesis this molecule using synthetic chemistry protocols.
Considering me as a fresher to synthetic organic chemistry, I'd like to learn more about the following questions.
1. What are all the different synthetic routes/steps that could be used to synthesis this compound?
2. How do I find the chemicals list, the steps involved, and the reaction environment required for this compound synthesis?
3. What are all the computational tools to predict the organic synthesis pathways?
If organic synthesis protocols for this substructure is available, please share them for references.
Thanking you
Hari Prasath Nagaiah,
Research Scholar,
Contact: +91-6382704953.
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Dear Hari,
many thanks for sharing this very interesting technical question with the RG community. We have 40+ years of experience in inorganic and organometallic chemistry. Thus I'm not a proven expert in multi-step organic synthesis, but for our organometallic research we synthesized numerous organic ligands. So I would just like to add a few personal comments in addition to the very valuable expert answers provided by Corentin Lefebvre. I did a quick SciFinder search and found that this molecule has never been reported in the previous literature. When you ask "What are all the different synthetic routes/steps that could be used to synthesis this compound?" my impression is that the answer can perhaps be found in the course of a Master or PhD thesis, but not within an answer on RG. However, in my personal opinion the main question is "Will this compound have any useful applications which justify the efforts of synthesizing it?". If not, it is perhaps not worth spending months to develop a suitable synthesis.
As for the possible purification, it is clear to me that the compound will be a solid, so that recrystallization will be the purification method of choice. Since it is a carboxylic acid, chances are that it could also be dissolved in aqueous NaOH and then precipitated again by adding hydrochloric aid.
Good luck with your research and best wishes, Frank Edelmann
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Hello Everyone,
Let me preface this question by saying that this is all being done under a legal THC/Hemp license in the state of Colorado.
I was hoping to get some advice on how to improve my method for converting CBD into THC. Currently we have been attempting two methods.
Method #1:
Combine CBD isolate (99%) with ethanol at a 10:1 ratio. Add 2.42g of p-TSA for every 100g of CBD isolate added. Reflux at 63C for 47min. Following the reflux we do a bicarbonate wash to neutralize the pH followed by an extraction of the cannabinoids into an organic layer (Hexane) by titrating water into the solution. After separating the phases we evaporate the Hexane out of the organic layer and distill the remaining oil using short path distillation.
The purity tested by HPLC is approximately 50% Delta-8 THC and 15% Delta 9 THC. Following this reaction the end product is prepared for oxidative degydrogenation to form CBN. The higher the purity of Total THC prior to this reaction, the higher the purity of our CBN. This we are looking to make improvements to our methodology.
Points or potential improvement:
1.) commence reaction under a nitrogen atmosphere
2.) use 200 proof ethanol (currently using 190 proof)
3.) change reaction solvent to toluene/heptane
Methods #2:
First dry your clay in a vacuum oven at 80C with a vacuum applied for 1Hr. Then combine CBD isolate with T-5 acid washed clay with 16% T-5 by weight (150g T-5 for 1000g CBD isolate). Reflux at 180C for 3Hr. Following the reflux distill using short path distillation.
This method has yielded us ~60% total THC. I’m not sure what improvements I could make on this methodology are.
Thank you all for any advice and insights you may have.
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Kyle,
You can contact us for consulting services.
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I've just tried to prepare several tertiary alcohol from benzoate with Grignard reagent. And I noticed that those benzoate bearing an unsubstituted amine show great difference in yield when amine group was on different site.(4 equiv. of EtMgBr added into a solution of aminobenzoate in anhydrous THF at -70oC or 0oC )
2-aminobenzoate gives excellent yield(>90% in most cases) but 3-aminobenzoate gives poor yield(less than 20% or even messy). Only those protected or substituted 3-aminobenzoate worked efficiently with Grignard reagent.
Is there any literature explaining this difference? Or someone is interested by this phenomenon?
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Dear Rengwei, thank you for asking this very interesting technical question. I think that Kohei Torikai already provided a good and plausible informatiom why the yields of tertiary alcohols were lower in the case of the 3-aminobenzoate reactions. One way to circumvent this problem could be the protection of the –NH2 functional group by acetylation. This has been described by Palomo et al. in the artcile entitled "Enantioselective Synthesis of Quaternary D4- and D5- Dehydroprolines Based on a Two-Step Formal [3+2] Cycloaddition of a-Aryl and a-Alkyl Isocyano(thio)acetates with Vinyl Ketones":
The paper has not been posted as public full text on RG, but the Supplementary Information is freely accessible. Please find attached a pdf file. As can be seen in the attched reaction Scheme, the 2 step-reaction of the N-acetylated 3-aminobenzoate with methyl magnesium bromide followed by de-acetylation (described on page S14) provided the tertiary alscohol in fairly good yield.
Good luck with your work and best wishes, Frank Edelmann
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I want to try this algorithm, but can't find a downloadable link or any data regarding its access and usage conditions, any help would be appreciated.
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I haven't used it but would DeepFrag https://rxivist.org/papers/127442 help you?
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Au(III)Cl3 + Ag(I)TFSI in methanol -> Au(III)TFSI3 + AgCl (s)
and then, I will remove AgCl precipitates by filtration..
If this is impossible, what solvent or what method should I use?
(because HAuCl4 can be produced, water cannot be used, maybe)
best regards.
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Dear Hong-I Kim many thanks for your interesting technical question. In general, the suggested reaction makes sense. Personally, I would use a more inert solvent such as dry THF. In THF the AgCl by-product should also form a precipitate which should be easily removed by filtration. Just give it a try on a small scale first.
Good luck and best wishes! 👍
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Example: 3-acetyl-5-carbamoylsalicylic acid (OH, COOH, COCH3 and CONH2)
Likewise, how many different combinations are possible? Can it be penta/hexa-substituted? Exclude simpler functional groups like alkyls and halogens
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Dear Ehtesham Mohammed many thanks for your very interesting technical question. In fact, one could write an entire book about this. Very good examples have already been provided by Thomas Mayer-Gall, Ekaterina E. Khramtsova and Andy Towns. Benzene is certainly one the most useful building blocks in organic chemistry. Among the more unusual hexa-substitited examples with six equal substituents are hexacyanobenzene and hexanitrobenzene (see attached schematic formula). An intermediate in the synthesis of hexanitrobenzene is 1,3,5-triamino-2,4,6-trinitrobenzene, i.e. a hexa-substituted benzene derivative with 2x3 different substituents:
Synthesis of polynitro compounds. Hexasubstituted benzenes
and
Oxidation of poly(nitro)anilines to poly(nitro)benzenes. Synthesis of hexanitrobenzene and pentanitrobenzene
Surprisingly, I also came across an article in which a derivative of hexaphenylbenzene derivative with six different substitunents has been reported (see attached Figure). Please have a look at the article entitled
Synthesis and characterization of a hexaarylbene with six unique substituents
This is certainly rather unique!
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Hi all, I need to cleave the ester in Ethyl 2-amino-1H-imidazole-5-carboxylate to make the carboxylic acid and retrieve the product from solution to use in downstream applications of linking to amines via reductive amination using sodium cyanoborohydrde.
I tried to cleave the ester with 2M equivalents of KOH in 5:1 MeOH:H2O for 1H at 40C. After 1H, i added 20mL H2O to quench and then tried to precipitate my newly made acid by dropping pH to 1, however nothing precipitated out. I then tried to see if any of my product was unreacted by mixing with diethyl ether to see if any of the light brown color would transfer to the ether layer, but again, nothing happened, the ether layer is completely clear. I guess I should just boil off some water and see if it starts to precipitate out? Im not much of a chemist so I just wanted to make sure I havent made any terrible assumptions along the way...
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Ester can cleaved by boiling it with aqueous ethanolic solution to form acid salt and alcohol. Neutralization of solution with HCL gives an acid.
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The background of this is lengthy, but in short, I am an experienced chemist with essentially no experience doing Grignard reactions.
Most recent literature uses mmol scales @ 0.1-1M concentrations. I need to run a ~1mol reaction, but multi-liter is out of the question. Small scale tests showed that concentrated solutions - but still with several equivalents of Mg-coordinating ether - were *extremely* viscous. No crystals or precipitation, but gelatinous to the point of not stirring. The reactions did not proceed as expected.
Very old mole scale literature usually uses Et2O.
Can someone with first hand experience on preparative scale Grignard rxns give me a feel for the maximum concentration of PhMgCl I should make from Mg/PhCl in THF?
I may need to run the reaction in several batches depending on the answer.
Thanks
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Dear all, attached is a book dealing with tips and practices in manipulating air sensitive chemicals. Under the circonstances you want to work, the best option is to work with a continuous lab flow reactor. Please check the link below. My Regards
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Hi Guys,
I am working with purification of gels, by washing with some solvents, so that, impurities get removed. But while doing that, I am getting some cracks after washing. I have fabricated gels by using polyesters using a bifunctional crosslinker, and I got a network also through esterification reaction. I used here EDC and DMAP as catalysts. I have used various solvents, like DMF, DMSO, Water, Chloroform for washing. but it didnot work. Could somebody share any idea to avoid this problem?
Kind Regards
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How soft has been your gel? I am working on soft gels that are difficult to be purified. I have to purify them by membrane dialysis, which creates another issue that is the low concentration of my gel due to the osmosis phenomenon.
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I'm trying to react Ar-CL compound (200mg) with a primary amine (1.2 equivalent), and I've found in the literature that they're using a very low amount of solvents (like 0.5ml) to proceed the Ullman coupling; how could this amount dissolve the reactants and the catalysts?
In fact, there're a lot of reactions I've seen being proceeded in a very low amount of solvent, but when I do them in the lab, I use something like 10x of the amount of solvent used in literature as I "feel' that the amount used in literature is very low to dissolve the reactants and the catalysts.
How bad could this affect the rate and the efficiency of the reaction?
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0.5 ml is a fairly small volume of solvent, however, if it's reported that way in literature, it sugests that your Ar-Cl would have very high solubility in DMSO and hence 200 ml should dissolve.
I imagine like most people have commented, that the reason for such low volumes is to aid isolation of product, given the difficulty that comes with using DMSO.
I expect that your amine is either liquid or dissolves in a separate volume of solvent??? I also imagine the reaction does not require stirring with would be inefficient in such low volumes.
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Column chromatography with Silica Gel columns with inbuilt UV detector.
Compound structure is mainly poly unsaturated fatty acids and analogs without UV handles.
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You have answered your own question. Proper chromatography methods require detection methods which are applicable to the samples under analysis. You may want to review the types of instruments, detectors, columns and materials available at your school before deciding on a final approach. Have someone in the school's analytical instrument lab assist you.
For HPLC samples with weak or no chromaphore, you will need to use a detector that does not rely on wavelength based light absorbance such as an RID, ELSD, CAD or MS, to name a few. Put a little time into researching this basic question so you will better understand the uses and limitations of these methods and detectors. I often suggest my students start with a keyword search on the web (GOOGLE or BING) to find examples and articles to review. This is one of the best ways to learn. Once you have familiarized yourself with the basics, be sure to ask your teacher for help in setting up and running some example methods.
BTW: You may also be able to derivatize some of your samples and use GC/FID or GC/MSD as an alternative to HPLC (only if the samples are appropriate).
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My di-phosphate salt compound contains two 3ry amino groups involved in salt formation and a one 2ry amine group that's not involved in salt formation. I wanna proceed N-Boc protection for this 2ry amino group; I'll proceed the reaction in water without using any bases.
Should I convert my compound to freebase first? or can I proceed it while in the salt form?
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I prefer to deal with free amines, convert to free amine then try to protect 2ry amine using 1:1 mole then check it's TLC , if their is more than one product separate by chromatography, after drying take IR, if the peak at around 3300 cm-1
disappeared and appearance of signals for Boc indicates the protection of 2ry amine
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I am running a Steglich Esterification with EDC/DMAP in CH2Cl2 on a with the carboxylic acid being a potassium salt that is p-sulfonated. Will the sulfonate group be effected by this reaction? I plan to extract by washing the reaction with brine solution to remove excess EDC/DMAP - does this seem plausible? I do not want to acidify the reaction.
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You can remove DMAP by trituration with ethyl acetate. DMAP does not soluble in EtOAc. Also I think you can run a short silica plug to remove DMAP and excess acid.
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Hello all, I was try to evaluate the antioxidant activity of some synthesized compounds. So,I prepared an ethanol DPPH solution with a [ DPPH]= 60 uM (2.3 mg in 100 mL of absolute ethanol) but when I measured the absorbance at 517 nm.
Firstly, I found an absorbance value of 0.214 which is in contradiction with the literature (~0.6 for this concentration)
Secondly,for the same concentration ([ DPPH]= 60 uM ), I found an absorbance value of 0.214 when I worked in the range  600-400nm and a value of 0.340 when I worked in the range 800-400nm.
Please some one can help me to solve these problems?
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dear
this article us good for your question
best regards
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The idea is to use base to create an anhydrous strong nucleophile, which needs to be as anhydrous as possible. Also the nucleophile should act as a sigma donor and not pi. Any leads is much welcome
Thanks
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The nitrile group is also in resonance with the carbanion
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how to stabilize the intermediate forms during inter conversion of one form the other?
is there any possibility of synthesizing the intermediates?
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Depending on the reaction rate you can lower the temperature to capture the intermediate and fraction collect it. You need to know the reaction mechanism to avoid conditions that might lead to decomposition. An other alternative is to make the synthesis if you know the structure, again, controlling the temperature.
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Are there any bioisosteric replacements of triple bond (alkyne) which were employed for lead optimization or scaffold hopping?
Thanks.
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Cyclopropene could be of interest
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I am trying to synthesize boronic acid pinacol ester derivatives from aryl/hetero-aryl halides.
Is there any TLC staining technique which can indicate the formation of boronic acid?
Thanks.
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Curcumin. Dissolve Excess household tumeric in EtOH and you have your stain. Boronic acids/ esters stain orange against yellow background
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My ammine part is only dissolved in DMSO and Aldehyde is dissolved in acetone, chloroform, methanol and others. What solvent should I use to form my desired imine? Can I use DMSO? WIll that may make any problem?
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May be you can useful from the following article
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I would like to request the Researchers to let me know any procedures or references to carryout synthesis of Schiff bases of 4-Aminosalicylic acid when treated with different substituted benzaldehydes, which results in good yields and requires simple work-up (high atom efficient other than Ultrasound technique or Microwave)
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K.A.Shaikh, V.A.Patil, A.M.Zamir ‘‘Solid phase promoted greener synthesis andantibacterial activity of novel Schiff base under catalytically free condition’’ Elixir Org. Chem., 43, 6960-6963(2012
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I’m trying to couple a perylene derivative with borate using Suzuki-Miyaura coupling reaction. (Please see the attached file for the structure of the compound and the reaction conditions) Several compounds of similar structure were already synthesized using Pd(PPd3)4 in THF/Water. However, the reaction doesn’t proceed for the structure presented in the file. How can the synthesis of this compound using SM coupling reaction?
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Dear T. G. Hwang,
No doubt Pd(PPd3)4 in THF/Water is a good condition for SM reaction towards synthesis of several similar compounds. But at some cases that may not give fruitful results even on maintaining inert conditions due to several factors like solubility, molecular stability to temperature, column purification etc., So, I would like to suggest you to have a trial with Pd(PPh3)2Cl2 in Toluene:EtOH:Water which may give you better result. And also I would like to recommend F.Nahra where Pd-NHCs are now playing a crucial role in SM couplings.
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It looks like the MC3T3 may produce as high, or higher ALP, without ascorbic acid, and this seems counter intuitive. Has anyone else seen this, or noticed it in the literature? Every study I have read used ascorbic acid, so I haven't found anything published on this yet. If MC's produce ALP then is the addition of ascorbic really stimulating ALP production from differentiation?
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Alkalen phosphatase is an enzyme that found in the most cells but have different tasks regarding to specific tissues. So it is found in MC3T3-E1 preosteoblast cells. Culturing it with ascorbic acid supplemented medium the ALP synthesis is triggered and increased in the cell cytoplasm day by day and reached maximum in general at day 14-21 in differentiation process.
For more infırmation please visit my article at my profile.
Best regards
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Hi, Can somebody suggest, How much equivalent of DMAP should be used in addition to EDC for esterification?
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Well, if EDC stands for the coupling agent (carbodiimide), you need at least 1 equivalent of it. DMAP can be used in catalytic amount provided that another base (like Et3N) is present in 1-1.2 equivalent.
Good idea will be to read the review recommended by Petr in the first post. Good luck.
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Can we calculate the molecular weight of a polymer with MALDI-TOF?
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I found this web page is very useful. I'd encourage you to take a look.
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Alexa Fluor 488 dyes are disulfonated analogs of Carboxyrhodamine 110. I have a protocol from a patent by Haugland. Has anyone tried synthesising this via some other method?
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Pratik
This chemistry work fine, almost as described in patent you were referring, but workup and purification is not straightforward, but works well according to this patent. Making NHS ester and its purification is more troublesome compared to making Alexa Fluor 488, it just hydrolyzes much faster compared to other NHS esters I worked with. Nowadays you can buy Alexa Flour 488 NHS ester and most of other Alexa Flours (kind of generic Alexa Fluors) at very reasonable price. Here is a link to one supplier.
Many other Alexa Dyes are available from
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Hello all,
I am using pure organic compound with good thermal stability and it is practically insoluble in most of the solvents as catalyst for C-C bond formation. I want to determine its nature in catalysis.
1. I am performing reaction in neat cionditions (without solvent) at 100 C temperature, at this I think some of the catalyst is soluble but I can see most of the catalyst solid present in the mixture.
2. som example reactions due occur at room temp where catalyst is completely insoluble
3. without catalyst reaction won't go, increasing catalyst amount has positive effect. but overloading of catalyst reduced yield.
4. catalyst has amine and carbonyl groups at portals
5. Hot filtration method shows reaction stopped after removing catalyst by filtration.
Now kindly answer following queries,
1. How can I decide my catalyst is heterogeneous or homogeneous?
2. is there any specific test to conduct?
3. Is there any small organic compounds known to act as heterogeneous catalysts?
thank you for your interest and support
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1. Based on your data, the catalyst seems to be heterogeneous. Increasing the catalyst amount does not increase the concentration of the catalyst in solution. "Hot filtration method shows reaction stopped after removing catalyst by filtration" indicates that the true catalyst is not in solution.
2. You have already conducted the "specific test"
3. I don't know, but why not.
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i want to prepare stable and pure phenylacetyl isothiocyanate from phenyl acetyl chloride. I tried the reaction with ammonium thiocyanate in solvent acetonitrile and toluene. But I am getting highly impure dark brown color oil.
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Use KSCN in the presence of dry acetone at room temperature stirring. Toluene can also be used to prepare isothiocyanate.
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I have a stainless steel mold, into which I pour uncured PDMS. The problem is after removing cured PDMS from the mold; I get sticky residual cured PDMS all over the place. Is there a good solvent or method that can remove the residual PDMS?
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Ideally there shouldn't be a residue (Kindly check the quality, proportion of polymer and curing agent and thorough mixing, plus use a glass substrate). IsoPropyl alcohol is the best way to remove the remaining uncured PDMS. The alternative is: Using Piranha solution (Hydrogen peroxide and Sulphuric acid in the ratio of 2:3 by volume). However, it's a highly corrosive acid which needs extreme caution while handling.
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What can be the best alternative for EDC, DMAP as catalyst for carboxylates? I want to skip DMAP actually.
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There's an odd esterification method involving CBr4 that's fairly selective, but might work, depending on the structures of your substrates:
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Hi Dear All,
Boronic acids in general form complexes with cis 1,2 or cis 1,3 diols etc. If we want to protect the boronic while attaching it to any polyesters with multi hydroxyl groups. Could somebody give a nice idea to do that?
Kind Regards
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Hello Rashid, here is a really good paper on the stability of boronic esters with various diol ligands and the rates of transesterification from one diol ligand to another.
The paper is on research gate and sciencdirect.
In general mixing a boronic esters and a diol in pentane for several hours, removing the water layer that forms, reducing the solvent volume and passing the concentrated reaction solution through a plug of silica gel with DCM as the eluent is a very effective way of esterefying and purifying a boronic ester. This is the method we often use in our lab. You can find the actual procedure in the SI of the Science paper on my researchgate profile. Here is the link to the paper http://science.sciencemag.org/content/351/6268/70
If you don't have access to Science Journal just let me know and I can upload the SI to my profile. Another common method that is used involves mixing boronic acids and diols in dichloromethane for several hours with a desiccants such as 4 angstrom molecular sieves (the method used in the first paper I mentioned).
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Hi All,
Could some one suggest an easy and efficient way to protect phenyl boronic acid with ethylene glycol?
Kind Regards
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I am trying to protect two OH with Boron, through its condensation with ethylene glycol. this picture with give you an idea.
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Dear All,
I am using EDC as catalyst with polyesters having 4 free OH groups, to form gel network, by adding a crosslinker. Problem, I am facing is, that when I add EDC.HCl, it forms a network prior to adding crosslinker. Normal case is, it should form network after addition of crosslinker and not EDC. Could some one share his experience or suggest something about this problem?
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Haroon
Your question is not clear to me. Please, use equation then you may send me on my e-mail and I 'd be glad to help.
Good luck
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Dear All,
I want to graft PBA (Phenyl boronic acid) with some polymer having pendant hydroxyl groups. From Previous literature and my own observation, boronic acid forms a complex with these polyols and forms a gel. I want to fabricate a gel system through chemical crosslinking at the end by adding a crosslinker, but i get a gel due to this complex prior to chemical crosslinking. Could somebody please suggest or share his experience that how can this complex formation b/w boronic and hydroxyls be overcomed?
Kind Regards
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you can protect the diol by carboyl group, and you can also protect the PBA pinacol. the later one is always supplied commercially.
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Dear All,
I have a question related to the swelling property of a gel. If the main polymer backbone has got hydrophobic character but the crosslinker has got hydrophilic property. Will it affect its swelling property in water? If yes, then, To what extent, Will it affect? Also please share any experience to impart hydrophilic character to gel through crosslinker?
Thank you.
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Dear Dr. Rashid,
There is a tailored interplay between a hydrophobic skeleton and hydrophilic spacers (crosslinking agents) in hydrogels that is regulated with concentration and molecular nature of both components. Besides, you have to take into account the segmental or/and molecular mobilities which may be constrained. So, I would like to emphasis two principal aspects (structural and dynamic) affected your balance in the polymer network. For each individual pair "polymer-c.agent" it is worth to elaborate the proper set of instruments which could give information on structure-dynamic behavior of gels.
Happy New Year
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We suppose that an activity aimed at the solution of this problem should be developed not only because of population upsurge but also in view of creation of underground civilization due to the possible future natural events incompatible with the comfort life on the Earth’ surface. We propose the Life Origination Hydrate Theory (LOH-Theory) as the theoretical basis of such an activity.
Plants, basing on minerals, create primary food substances, and animals, basing on these primary food substances, create secondary food substances for mankind. This work is being performed on the basis of quite definite chemical processes and is being governed by universal physical laws and chemical regulations. 
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@ Salvador Ramirez-Flandes: ok, I retract "absurd" and replace it by "improbable" or "costly to such an extent that it seems improbable to me unless we have access to so much energy that is is reduced to a secondary question".  
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I am presently using diethanolamine in water at pH 7.8-8.8 at 75C requiring about 12hrs to complete the hydrolysis.  This will be used for commercial production so large scale procedure is needed.
Possibly a catalyst on a solid support that is commercially available.
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possible reaction mechanism?
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There are different reactive sides in the two reactions
the it is difficult to precise the reactions products
But I think that they can produce 1,2,3-triazoe and thiazolone respectively 
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I have already found some information about my question on this site - https://www.gas-find.com/cyanure-de-potassium.html
So I need to be sure, that I have chosen the right one. 
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I have worked with liter quantities of liquid HCN, which requires elbow-length heavy gloves and a rubber apron.  I did not use a respirator, but worked in an efficient hood with the sash as low as practicable, and the apparatus mounted in a plastic tray or bucket large enough to contain a spill.  An emergency kit (syringe w/ thiosulfate solution) was kept at hand. 
I would recommend the same if dealing with large quantities of KCN, and as Veronika notes, would not work without a well-operating hood.  With appropriate equipment and precautions, a respirator is not necessary.
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n/a
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They are constitutional isomers (same molecular formula but different chemical structures) They differ via the position of the alkene (internal in alpha, terminal in beta).
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I'm trying to deprotect hexylamine protected with -Tos group, just to see if the reaction with SmI2/amine/H2O (said to be instantaneous) works.
I prepared the solution of samarium iodide, SmI2, (1,2,-diiodoethane and Sm in THF) and I get the blue dark color. I tried the reaction with Et3N as the amine, and when I ad this final reagent to the reaction mixture I get the color change as the articles say it woul do. However I can't deprotect my amine group. Any help?
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Why you go for a costly reagent when when a mineral acid will be able to remove tosyl group. 
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Does anyone have experience working with trimethylsilyl protected alkynes? I am wondering about their stability towards acids and bases.
Are they similar to silylethers?
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I agree with Nadeem A. Lodhi.
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I am trying to lithiate my compound(DTP) with TMEDA and BuLi(6 eq) for 1hr reflux(@ 80 degrees). It seems to be ineffective. Hence, I would like to know whether any other lithiated agent is there which serves my need?
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BuLi decomposes above 50oC.
Ziegler, K.; Gellert, H. G. Liebigs Ann. Chem. 1950, 567, 179.
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               I am synthesising N-(Benzyloxycarbonyl)-L-serine benzyl ester starting from N-(benzyloxycarbonyl)-L-serine by using benzyl bromide in aq. NaOH and Acetonitrile under reflux condition (by following a research article “Optimized synthesis of phosphatidylserine” By Guanti, Giuseppe et. al., From Amino Acids, 39(2), 367-373; 2010)
My questions
1) why no racemization was observed in such conditions?
2) If I run the reaction for whole night, is it possible to get racemization under such condition?
 Exact procedure is  N-(benzyloxycarbonyl)-L-serine (10.63 g, 44.4 mmol) was suspended in CH3CN (50 ml), and treated with 4 M aqueous NaOH (11.175 ml, 44.7 mmol). The resulting solution was treated with n-Bu4NHSO4 (1.52 g, 4.48 mmol) and BnBr (6.40 ml, 53.9 mmol) and refluxed for 4 h. After cooling to r.t. (a white solid separates), 5% aqueous NaHCO3 (55 ml) was added and the suspension stirred for 20 min. After removal of the solid through filtration, the two phases were separated and the aqueous one extracted three times with AcOEt (40 ml each). The reunited organic phases were washed with brine, well dried with Na2SO4 and evaporated to dryness to give an oil. It was taken up in n-hexane (40 ml) and stirred until a well solid separates. It was filtered on a Buchner filter and washed with n-hexane. Finally, the solid was crystallized from Et2O/PE to give pure N-(Benzyloxycarbonyl)-L-serine benzyl ester as white solid, yield (11.03 g, 75%). m.p. 81.9-82.6°C. Rf = 0.34 (PE/Et2O 3:7). 
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Hi. Sorry but the first thing I would do was to register the optical purity of your sample, the optical rotation. After that you and we may start to discuss or theorize concerning conditions, base, time of reaction and eventual implications and ways to tackle the EVENTUAL problem.
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This was a mitsonubu reaction performed between N-methyl diethanolamine, N-hydroxypthalimide (NHP), PPh3, DIAD, THF at 0 degree celcius, and stirred for 12 hr at RT! Any ideas will be appreciated. Thanks. 
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Sometimes Mitsunobu reactions can be a pain. TPP=O is relatively easy to remove if your material is soluble in ether. If so, make a conc solution in ether (with an ice bath) and add hexane or pentane dropwise (quite slowly .. a drop ~ every 10 seconds, to avoid losing product)  until the TPP=O crashes out, then load it directly onto a column or filter. the DIAD byproduct can be tough to get shot of. I have had luck changing mobile phase from Hexane/ethyl acetate to Hexane/diethy ether. Basifying your column or switching to alumina can also work. If all else fails you could try a DIAD alternative, the Brimble group put this out a few years ago, its a shorter prep than other alternatives and I'm told its the shiz  10.1002/ejoc.201403152. On a side note, I  have found that DCM is a really good solvent for Mitzy's and it doesn't require drying or inert atmosphere. Doing it in a sonic bath (the same type used for cleaning glassware) really speeds the process up and in some cases improves the yield.  
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Hi researchers.......
I have solid powder of carboxy phthalocyanine (PcCOOH) and want to convert it to -COCl. So can solid sample be converted directly to COCl by adding SOCl2 and refluxing or I have to dissolve it in some solvent to achieve individual molecular entity in solution. I am afraid if SOCl2 can reach between the stacked phthlocyanine molecules in solid sample. 
Thanks in advance
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To use SOCl2 as chlorinating agent you should use a solvent.
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I am able to tosylate 2-iodoprop-2-enol easily (>80%) but with 2-(4-iodooxazol-2-yl)prop-2-enol there is no conversion using the same method (NEt3, NMe3*HCl, TsCl). Can anyone provide an explanation? I cannot understand, why the oxazole should make such a big difference.
I have also tried DMAP and DABCO, but no success.
Does anyone have a possible alternative to introduce an alkyne in place of the alcohol?
Thanks a lot in advance!
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Thanks a lot everyone, I will look into this!
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I have been trying to do a reaction of DSPE with NHS-PEG-NHBoc to make DSPE-PEG-NH-Boc.  Maldi MASSS data looks like DSPE does not react with NHS. I checked temperature ,base . But still I have problem.  Could you suggest me anything about reason? I  saw couple of literature about it, increased temperature up to 50degree and used Base DIEA. I still did not get expected result. I need some suggestion from you guys if you have any idea. Thanks in advance. 
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I am sorry I got here late (a random google search on similar items brought me here). This is (very likely) same as what happened to me when I was mixing mPEG-NHS and phosphatidylethanolamine well back into last century (see PMID: 2384160 in pubmed for details). First time I tried this synthesis, it did not work. Turned out, NHS ester was hydrolyzed almost completely when it was shipped to me by the manufacturer. They have replaced it with the new material, and it worked fine, so that paper was published and still cited. NHS ester degradation can be tested by a simple UV experiment: the active ester does not absorb at 260 nm, but hydrolyzed free NHS does (in mild alkaline conditions, eg PBS, HEPES or borate - the higher the pH the faster the hydrolysis - so you can get the whole hydrolysis kinetic curve and find out how much NHS was there in free form or as an ester). Molar extinction coefficient is ~8200, if I remember correctly, so you only need a fraction of a milligram to test. I teach this analysis technique to UVA BME undergraduates as a part of my liposome module in their lab class. Take some in methanol or DMSO solution of your NHS ester and squirt into PBS that is already in the spectrophotometer cuvette and zeroed. Mix very well, and start measuring.  So you do not even need NMR...
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I am currently trying to validate VOCs that are not present in the SIFT-MS compound library. The commercially available standard only exists as a mixture of stereo isomers (cis/trans). Before we try to isolate the isomers, which is time-consuming and still in need of a lot of experimentation, I was wondering if the different isomers can have different product ions or if it will just be the same product ions with different branching ratios?
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I am sure there should be a difference - after all, cis/trans isomers may behave differently in chemical reactions (and chemical ionization is a chemical reaction !). One can speculate that certain cyclization or fragmentation reaction would be possible for only one of cis/trans isomers. However I cannot give examples; also I don't know how big could be the difference and under which conditions it would be really noticeable. It would be good to hear the opinion of experts in mass-spectrometry.
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Hi everyone
I am trying to synthesise FeBr2THF2 from FeBr2 and THF but the reaction doesn't seem to work for me.
FeBr2 is stored in a glove box, THF is dried over sodium and benzophenone and the extraction carried out under an inert atmosphere. Conditions i use are 25g of iron bromide and about 150-160ml of THF refluxing for about 8hrs. I never observe white crystals as reported in literature. They didn't say how much THF they use although they used 100g FeBr2 for 12hrs reaction. I am limited to about 100ml of THF due to Soxhlet extractor size. If you have any hints or tips please share.
Thanks.
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Thats correct if i remember correctly. this was a few months back and i have dropped this approach since then 
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I want to obtain a solid by precipitation. I used two antisolvents ( dietheyl ether and petroleum ether), after I put the mixture in fridge. I obtain after that kind of crytal shapes. I want to filtrate under vaccum to get pure crystals. HOEWEVER, after some time the crytals (solid) disappear! Any explanation to this phenomenon? and what should I do to keep my solid?
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It sounds as though your crystals may also be absorbing water from the air and then dissolving in it. If may be worth filtering through a Schlenk flask with a frit, so that you can keep the atmospheric water out, and storing the solid under nitrogen or dry air.
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A compound I wish to synthesize requires a preliminary nitration step, and I have several questions about how to best do this with my available reagents, as well as general guidelines for doing these reactions.
Regarding the nitrating reagents, red or white fuming nitric acid is not available in our laboratory, and we only have access to 70% nitric acid, as well as KNO3, NaNO3 and NH4NO3
The only literature procedure available for this compound requires the use of fuming nitric acid, and acetic anhydride as solvent. I attempted it using our 70% solution and it gave very poor results.  My aromatic system is moderately deactivated with no electron donating groups, and I suspect that the water in the 70% solution is problematic here.
Using the 70% solution, I am under the impression that with concentrated H2SO4 as solvent/acid/dehydrating agent, the mixture should be strong enough to allow the reaction to take place.
1) About how many molar equivalents of HNO3 would you generally add, and about how many milliliters of concentrated H2SO4 do these reactions require per milliliter of 70% HNO3 to get adequate dehydration? Just looking for a general range.
2) When quenching the reaction, about how many milliliters of ice water do you pour the reaction mixture into per milliliter of concentrated H2SO4?  Again, I'm just looking for a general range.
Additionally I've seen a number of procedures for nitration using either KNO3, NaNO3 or NH4NO3, in conjunction with Concentrated H2SO4 to produce anhydrous nitric acid in situ.
3) Which of the Nitrate salts do you prefer/which have given you the best results?
4)  Most procedures I've seen with the in situ generated HNO3 are as follows:
a) premix H2SO4 with 1.1 equivalents of the nitrate salt and add this solution to the substrate in H2SO4 at 0˚C,
b) portionwise add 1.1 equiv. of the solid Nitrate salt to the substrate in H2SO4 at 0˚C
c) Slurry the substrate in CH2Clwith 1.1 equivalents of the Nitrate salt at 0˚C, and then dropwise add H2SO4.
If you have done one of these, which ones worked well for you?
I attempted procedure "b" with NaNO3 but it seems to dissolve very very slowly in the H2SO4 solution at 0˚C, and is still pretty slow even at ambient temperature, and it seems likely I could get a large temperature spike on larger scales if the heat of the reaction rises too quickly causing the undissolved NaNO3 to dissolve and then react, making me hesitant about using this procedure.
5)  For these reactions done in a chlorinated solvent with H2SO4, Will there be any issues with the slight (0.1 equiv.) excess of HNO/ NO2+ reacting with the solvent that I need to worry about? Or is CH2Cl2 relatively inert under these conditions?
Thanks in advance!
-RL
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I've done nitrations using fuming sulfuric acid (oleum) and solid sodium nitrate.  Dissolving the nitrate salt first is a good idea, as you can do that at room temperature, then cool to 0ºC.  The nitrating strength is a function of the water content, and you can "tune" the reagent by adding water to moderate it, or SO3 to boost it.
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How to prepare zinc carbonate ? is there any process for the separation of Zinc carbonate from  Magnesium carbonate?
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By reacting a soluble zinc salt such as zinc sulphate with a solution of sodium carbonate. The products are zinc carbonate (which is insoluble and forms a white precipitate) and sodium sulphate which is very soluble and so remains in solution;-
ZnSO4(aq) + Na2CO3(aq) → Na2SO4(aq) + ZnCO3(s)
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I'm looking for standards of these compounds to quantification of my products. 
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Thanks for the answer. I have already contacted LGC, and they said that the product is no longer available.
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Hi, I have trouble cleaving off the phenyl glycinol chiral auxilliary from my amino acid analogue. I have only tried oxidative conditions, (PbOAc4) varying the reaction time, temperature and solvent. I am reluctant to use hydrogenolysis due to the fact that my molecule is labile in reductive conditions. Any suggestions?
Thanks.
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@Athanasios
I assume that you are trying to oxidize the attached chiral auxiliary into the corresponding benzaldimine for subsequent hydrolysis into the free amine. 
Have you considered sodium metaperiodate (NaIO4) or a related reagent? Please see the references below. NOTE: Be careful when handling reactions that require or generate large amounts of periodic acid. It is a strong oxidizer and highly corrosive. 
• From U Bologna and GSK in Italy: 
"Asymmetric Synthesis of 1-(2-Pyrrolyl)alkylamines by the Addition of Organometallic Reagents to Chiral 2-Pyrroleimines"
• From Pfizer: 
"Practical enantioselective synthesis of beta-substituted-beta-amino esters"
• From Pfizer. See Supporting Info: Compound 16 to Compound 17:
"Pilot Plant Preparation of an αvβ3 Integrin Antagonist. Part 1. Process Research and Development of a (S)-β-Amino Acid Ester Intermediate:  Synthesis via a Scalable, Diastereoselective Imino-Reformatsky Reaction"
Admittedly, I have only cleaved similar auxiliaries by hydrogenation. Hope this helps!  
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i tried by this method 
5-bromo pentanal & (4-Carboxybutyl)triphenylphosphonium bromide in presence of NaHMDS in THF SOLVENT , i got product but very low yield & HNMR shows desired compound signals along triphenyl phonium oxide , plz suggest best method 
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cross metathesis is possible too but the reagents needed may not be readily available.
I think the Wittig or HWE reactions will be problematic as there are several sites e.g. ester or phosphonium/phosphonate and aldehye/bromo/ester. It looks like a lot of optimisation is needed to find the right conditions.
should consider using temporary protecting groups instead of the bromo or ester
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Maybe i think 5 position of phen was nitration by HNO3 and H2SO4 and Br- in NaBr reducted nitro group in phen. But, how can phendione be produced?
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Jae Jun Lee:
                         The electrophillic substitution reactions such as nitration on the aromatic hydrocarbons phenanthrene and1,10- phenanthroline are generally difficult/complicated. That is due to the higher reactivity of the functional unit (that may not be real part of aromatic system as shown in attached file) toward addition reactions. Due to its typical reactivity, this structural unit generally behaves like alkene in few reactions and is more prone to give addition reactions rather than substitutions. In your experiment, you have used two oxidizing agents such as nitric acid acid and sulphuric acid. There may be many complicated processes involving in the oxidation. The most reasonable is given in the attachment.
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I'm attempting to synthesize palladium pentafluoropropionate via ligand exchange starting from palladium acetate.
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Ian, the direct reaction you are using should be fine.  We use that method to form amino acid complexes of palladium, although we tend to use a methanol/water mixture.  I can guess that the product is not going to be an easy one to crystallize.  Pd(OAc)2 is a trimer and it is not certain to me that the fluoroethanol analog will be.  We also find that many of our amino acid  complexes hold on to various amounts of water in making suitable crystals and you may need some suitable solvent there as well.  If NMR spectroscopy leads you to believe you have the desired material, experiment with different solvents and mixtures to try for crystals.  Do you have MS analysis?
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A similar reaction with a t-butyl substituent on the 2-position on the phenol is complete in 1 hour without a solvent at 105 degrees C. It also works by refluxing overnight in ethanol. These methods were tried but not successful. Reflux or heating for a longer time didn't work.
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I would say heat it higher until it either reacts or begins to decompose.
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I am trying to attach N-Boc-3-bromopropylamine to both of the phenols of 7-hydroxycoumarin dimer with no success. I have tried K2CO3 in DMF at 80C, Cs2CO3 in DMF at 60C, TEA in DMF at 80C, DMAP in DMF at 80C & 110C but have not formed the desired product in any of these conditions and have seen significant side reactions. Does anyone know a set of conditions I should try (especially varying the solvent used as I have only used DMF)? I have attached the structure of the desired product.
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 during your synthesis,  dissolve your 7-HC first in DMF+ K2CO3 (Make sure that k2CO3 must be in dry form). stir it for few min and add N-Boc-3-bromopropylamine drop wise. Maintain temp as mention by Syeda Aaliya Shehzadi in previous reply.
After completion of reaction, Pour whole mix in Crushed ice for overnight. Filter the product and Check in TLC.
All the best 
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i ran a pectet-spengler reaction using equimolar amounts of tryptamine hydrochloride and aldehyde refluxed in methanol with catalytic amount of acetic acid but even after 107 h, both reactants did not consume completely. reaction was also refluxed in acetic acid with TFA as a catalyst. i think it might be because  tryptamine hydrochloride was present in salt form or due to schiff base which is intermediate. i plan to neutralize tryptamine hydrochloride and neede guidance. thanks
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If you want to isolate tryptamine as a free base from tryptamine.HCl it is better to stir the salt with little more than equimolar sodium carbonate in methanol/acetone for 1-2 hr and then filter the inorganic material . Now you have free base in filtrate and use it for onward reaction.I hope it will work nicely.
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I've been having trouble trying to purify 3-methylnona-1,8-dien-3-ol from a grignard reaction utilizing vinylmagnesium bromide. There is a file attached the shows the synthetic scheme. I'm not completely sure what is going wrong, but I obtain about 6-7 spots on TLC after the reaction is quenched and worked up. Has anyone had trouble with side reactions during grignard and ketone reactions? Any advice helps! Thank you!
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It could be due to conjugate addition etc.  We have had a lot of success using either CeCl3 in the reaction to promote 1,2-addition, or LaCl3.2LiCl solution. In either case just stir the ketone with the lewis acid for about 30 mins, then add the organometallic over a few minutes.
best of luck
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I am having problems making free flowing slurries with Silica Gel particularly for sticky substances.
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It deepens on the substance and the substance to silica ratio, dissolve your substance in a solvent, such as DCM or MeOH add the silica and evaporate slowly under mixing. If still sticky, add solvent and increase the amount of silica.
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I came across this reaction in literature where they successfully reacted delta-valerolactone (5 membered ring) with LDA. I've tried the same reaction substituting this valerolactone with the PDL but with no success. Is omega-pentadecalactone lactone less reactive because it is bigger?
Will using NaNH2 instead of LDA be more effective?
All help is appreciated. 
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I assume that you are trying to generate the lactone enolate anion.  For various reasons, including reactivity,  NaNH2  would not be a good choice for a base.  The bases suggested should work depending on the solvent being used  and how much the alpha methylene to the  carbonyl may be sterically "sequestered" by folding of the ring.  I would suggest KH in THF as an alternative as KH possesses very high reactivity and cleanly forms enolate anions in THF. 
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In desulfurization of fuel oils I found an article that explains the capacity of  1860 ionic liquids to Thiophene and Dibenzothiophene.
I would like to know how to carry out COSMO-RS Study ?
here the attached article
Desulfurization of Fuel Oil: Conductor-like Screening Model for Real Solvents Study on Capacity of Ionic Liquids for Thiophene and Dibenzothiophene
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I think in these papers they correlate the capacity for a solute in an ionic liquid to the infinite dilution activity coefficient (IDAC). IDACs are calculated with any COSMO-RS implementation for your solute + solvent combination from the sigma profiles. Tamal Bannerjee (IIT Guwahati) has also quite a few papers on this specific subject (desulfurization with ionic liquids) 
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I ran a sephadex column with 50%CHCl3:MeOH solvent system. In first 10 vials, i got a mixture of compounds with tails (streakings) after i run the TLC. But i got 2 compounds in next vials. Should i run this mixture of compounds (present in first 10 vials) again in the sephadex lh-20 with same 50% CHCl3:MeOH or i should better use 100% MeOH solvent for its purification?
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Dear Sir
Please, find in attch, an Instructions 56-1190-97 AD Gel Filtration for Sephadex LH-20. It might be useful for you.
Best wishes
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Usually, using less amount of solvent in a reaction gives better yield and hence, a pure reaction. In some literature, i found that they have used 20 mL solvent (MeOH, MeCN, ETOH, etc.) in preparation of Schiff Base while it could be used upto 5 mL or 3 mL. Is there any relationship between Synthesis of Schiff Base and Solvent Volume? Identification of Schiff Base is also a dificult in some reactions where it is not precipitated out. any trick to identify that?
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Thanks Dr. Madhukar Baburao Deshmukh, would you be kind enough to elaborate the ratio which you mentioned as 1:10? Is it 1g or 1mg to 10mL?
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This organic acid also has a relatively non nuclephilic hydroxyl group. I need to activate a carboxylic acid.
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Pentafluorophenol esters used to be common active esters in peptide chemistry. They are easily prepared from the acid, pentafluorophenol, and DCC or DIC (1 eq each) in e.g. dichloromethane. Mix, stir, work up after a while (check w/ TLC).
No need for activating the acid in a separate step (acyl chloride or anhydride) or activating the alcohol as Pratik ended up doing.  
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How to prepare calciumthioglycolte from 80% thioglycolic acid, we are preparing aqueous media its coming clear solution please give any suggustion. which solvent is suitable for this reaction.
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I would suggest reaction of an aqueous solution of thioglycolic acid with Ca(OH)2, which is slightly soluble in water. The only byproduct will be water, as the hydroxide ions are protonated.
Alternatively, calcium oxide and calcium carbonate could be used, but I think both are less desireable than calcium hydroxide. Calcium oxide will react exothermically with water to form the hydroxide, and the carbonate will produce carbon dioxide as a byproduct in addition to water--vigorous bubbling is likely undesirable given the stench of thioglycolic acid...
More soluble calcium salts like calcium chloride are also an option, but the extra ions might complicate isolation and purification of the desired product.
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Hi there,
so far i am getting the references and patents on synthesis of PESA using catalysts like Ca(OH)2, Ammonium Persulfate and other free radical initiators. However, i am not sure which of them I can use to produce PESA on large scale, (I mean on commercial scale). Please share your answers.
Regards
HEmant
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You can use Ca(OH)2. Please see files:
file:///C:/Users/w7/Downloads/doc.01%20(1).pdf
file:///C:/Users/w7/Downloads/CE009.pdf
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I have 3 hydroxy group in my molecule and I want to convert it to azide.
I tried several methods like tosylation azidation, mesylation azidation etc, but it is not working in my case.
Any idea why tosylation does not go?
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What do you mean by "3 hydroxy group" ?
In chemistry, and especially in the chemistry of azides which are high energy compounds, it is important to know exactly what you need to accomplish. Otherwise it is hard to suggest/predict what may happen. If you meant a tertiary hydroxyl group, then it may be particularly difficult. I would try DPPA/toluene at 80 degC and hope that the reactivity of your molecule allows for the desired process to occur.
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TbCl3, EuCl3, Gd(NO3)3 are the salts. 
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