Synthetic Medicinal Chemistry - Science topic

I am looking for suggestions of small molecule commercial drugs which can be synthesized in less than 5 steps. Preferably the drugs approved in the last 2 decades.

Thanks.

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?

When I synthesise ester derivatives from pyridin-4-ol why do they turn to keto-enol tautomerism, do both hydroxy and NH parts react wth acid?

Are there any bioisosteric replacements of triple bond (alkyne) which were employed for lead optimization or scaffold hopping?

Thanks.

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.

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)

When the compound is formed as a salt in the reaction, can NMR be used to identify if the compound is de-salted?

I mean, will the 'H' of HCl salt of my compound be identified by NMR?

Thanks.

Hello,

How can we develope a chemotherapy that can only attack the cancer cells? Any idea?

Thanks

I want to know how we can develop a scheme to synthesize a new molecule.?

How to design a new scheme ?

Senior Researcher having experience in Drug synthesis please share their

views, idea , anyone from Harvard University ? write me back.

 Thank you

Sunil Kumar

Any Researcher working on lead molecule , screening . please share their experience with me.

I want to know the exact route to develop a new molecule. 

Thank you

sunil kumar

when i try to n-alkylation of aminothiazole in ceftazime use base and heat between 60-70 in dmf the pyridine ring liberate and i know from it is smell and color of pyridine? how can i overcome this? please i need help 

Procedure reported in literature by using concentrated Sulphuric acid and fuming Sulphuric acid is not working.

Hi all,

I am looking at calculating transition state energies of triazoline degradation in the prodrugs I am synthesizing. It is the step between step 2 and step 3 (in the attached figure).

The protocol I am following at the moment is to use Avogadro to conduct a systematic rotor search (conformer search) to find the conformers at local minima and subsequently conduct a optimization and frequency calculations on Gaussian 09.

I am having issues with finding a suitable conformer. As Avogardo does not provide the same set of conformer every single time I conduct the "systematic rotor search". And also on conducting an energy minimization on the obtained local minima conformers the energy drops further leading to a totally new conformer.

Can you suggest any better way of doing this?

Thank you.

Regards,

Siddharth.

I have found an excess of benzylamine in my synthesized product. I am trying to remove various methods but all went failure. So Friends help me in removing benzylamine from my synthesized compound. Moreover my compound is a pyridine moiety. Requesting you all to help me

Thanks in Advance

Ajay

UGC-BSR Research Fellow

Annamalai University

Does anyone has done selective deprotection of methyl ester of sialic acid in presence of pivaloyl group?

when I react the acid with aminoguanidinium hydogen carbonate by fusion the yield is so small 

Using ter-butylamine and Br2 (2:1 ratio) at -70 Celsius and methylene chloride as a solvent.

previously i was used this procedure

Please provide me with the appropriate publications or the catalog numbers of the commercially available anhydrides.

If expanding the ring structure from 5 member to 6 or 7 , then what is the effect of ring size on the MDR, bioavailability and cytotoxicity in general. 

I have a crude reaction mixture, consisting of Potassium Carbonate, organic polar compound (the required one) and some polar but possibly organic impurities. I have possible two options to workup. Is it better to first perform aqueous washing to remove potassium carbonate and then run column chromatography to purify my required compound from impurities. Alternatively, i should better run column chromatography directly instead of aqueous washing because potassium carbonate is ionic salt and may stick on flash silica which could possibly give me my required compound as fully pured. What type of workup should i go with? I am interested to seek answers from respective expertise in the field of Synthetic Organic Chemistry or as relevant.

can I use PPA as solvent or just little amount of it to complete reaction.

Please provide detail procedure of benzoxazole synthesis. Pl provide references.

Thanks in advance

Need a process for the bulk synthesis of 4-(4-HYDROXYBENZYLIDINE)-P-FLUOROANILINE by using other starting material which is already patented by these two starting material for Ezitimibe

I am doing a Cadogan reaction and I have a difficulty in isolating my target compound from a gummy product. 

Acetophenone Phenylhydrazone was synthesized and obtained as good yellow crystals after re-crystallization from ethanol. The formed crystals on exposure to air (air drying at room temperature) became brown (after 4 hrs) and turned into dark reddish-brown color (after 15 hrs) and started to liquefy (16 hrs).

Can anyone suggest me why this decomposition is occurring and how to prevent this?

Can anyone explain the detailed mechanism of IBX synthesis from Iodo benzoic acid and oxone in water?

Enzymatic or chemoselective resolution of corey lactone benzoate. Any literature references are most welcome.

Benzyl bromide and the product formed are soluble in organic phase like ethyl acetate, the excess of benzyl bromide present in the product may lead to its deterioration. How does one separate excess of benzyl bromide to get rid of this problem.

What are the optimum condition for a nucleophilic substitution reaction involving 4-aminophenol, so that the phenolic OH is only allowed to react keeping the aromatic amino not involved in the reaction. How will solvent selection affect the reactivity, and what is the most suitable solvent?

Can anyone tell me whether a pyrimidine derivative is possible from mannich product (beta keto amine) by condensation with urea with suitable catalyst? I have synthesized 2,4,6 tri substituted pyrimidine derivatives from chalcones, now looking for 1,2, 4 trisubstituted derivatives.

I am using PASS online software for docking newly synthesized molecules, but I am unable to understand what Pa and Pi value indicates and which one is better for biological activity.

My compound contain C, H, N, S and i have done C, H, N analysis. Can anyone suggest how to calculate exact composition of C, H, N, S based on the C, H, N analysis data?

In view of NaCl importance in human beings is it a micronutrient?

It is essential component of food, composed of Na & Cl. I would like to know that NaCl (Sodium Chloride) is under the category of Micronutrient?

Please give answer in view of both Plant & Animal.

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Structure of compound is confirmed by HNMR, IR, MS and elemental analysis.

The mechanism of reaction of conversion of the compound is 7 to 22 in the attached file. It is called Venuti's method.

We are doing an anti-cancer test. When we dissolve the comp with DMSO, it dissolves. But when we add medium (DMEM or Tween20), it starts forming precipitate. Does anyone know how to solve the problem?

I need to open an epoxide on a complex molecule with a primary TBDMS group

I am using acid chloride as reagent.

I do know some of them like Boc, but I am looking for a small protecting group and not bulky one! Also, is MOM(Methoxymethyl ether) a good one or not? Thanks!

I am worried about the epimerization at the alpha C with respect to the amino group.

I need to synthesise 5,6,7,8-tetrafluoro naphthoquinone or 5,6,7,8-tetrachloro naphthoquinone.

Any suggestions for the synthesis of either of these chemicals ?

CH3F, CH3Cl, CH3Br, CH3I.

Recently I am involved in the modification of cyclodextrins. How best to remove modifying particles from the interior of cyclodextrin. These compounds are soluble in water, methanol and ethanol. Thanks in advance for your help

What do we need to consider when developing an inhibitor?

I have synthesized 6-nitroquinazolin-4(1H)-one following the Niementowski protocol but have problems with dehydroxy-chlorination? This should be a fairly simple reaction to perform but I have tried several inert conditions, 90 - 160°C, 1hr - 6hr reactions using the above listed reagents, but had no luck. I only recover my starting material or something else. If you have particularly carried out the reaction please suggest a trick to this reaction; could it be that I need a little atmospheric moisture or maybe there's a way to shift quinazolone equilibrium to a 4-hydroxy somehow besides using the above reagents?

There is a software named OSIRIS that predicts the toxicity of some systems. Is there any online resource to calculate the toxicity of the newly synthesized compounds?

Recently, I use DCC to carry out amide formation (the last two weeks). And now I have some areas of my skin with a little bit of dermatitis (forearm, neck and armpit). I have taken care about using gloves but maybe it was not enough. Does anybody know if that is possible and the type of allergic of DCC and another coupling agents? I have read something about that but any testimony of someone with the same problem. Thank you very much in advance

I am trying to cleave the Tr from aziridine using TFA/DCM/MeOH. But I am getting ring opened product. Please help me with a suitable method.

We are doing amination of 2-chloro pyridines without palladium chemistry,while our molecule have one functional group which falls a part above temp.100 degree C.

So anyone is familier with favourable condition?

I have reduced a nitro to amine using SnCl2 under acidic conditions, neutralized the solution using NaOH and precipitated Sn(OH)2 and crystallized a product (amino acid) from aqueous solution using AcOH. Normally this reaction gives good yields but this time the yields are very low (less than 20%). Could this be the work up procedure (co-precipitation) or scale of crystallization...any ideas?

Most chemical preparations involving extraction of aqueous layer involve drying the solvent (MgSO4, CaCl2, P2O5, you name it) prior to its evaporation. Often it seems important but I think it may not be necessary in every case.

I'm trying to do a reaction between an alkyl iodide (a little bit unstable) and piperazine, in order to obtain the monoalkylated piperazine. However, I'm having trouble obtaining a good yield and controlling the mono/dialkylation ratio. Could anyone help with suggestions?

Its an aromatic aldehyde with ortho-piperidine and meta-bromine substituents. I have tried

I was wondering if the carboxylic acid should be protonated or not in order to decarboxylation to happen.

I just need the reference title, volume, title, year and issue no where it was published.

I need synthesize compounds of the type R-CO-NH-R(amino acid), but I am having problems with protecting groups.

If so what is the reason?

Tips about mobile phases would also be useful.