Science topic

Amide Synthases - Science topic

Enzymes that catalyze the joining of either ammonia or an amide with another molecule, in which the linkage is in the form of a carbon-nitrogen bond. EC 6.3.1.
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I have amidation reaction in DCM using DCC. I can separate the bi-product through centrifuge or filtration. I am wondering what is the best solvent to precipitate the product ? either using cold ethyl ether or cold MeOH ?
Thanks.
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You can use hexane or DCM for precipitation process
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The synthesis of certain ligands and amide complexes is difficult. I would like to try to do it using a microwave.
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Microwave for use in the synthesis of ligands and complexes is not different from regular synthesis. Avoid the use of volatile solvent . Carry out most of the reactions in water. The main problem with the microwave synthesis is to adjust the power for controlling temperature carefully. Synthesis of ligand is similar to the synthesis of organic molecules where as for complex formation temperature below 70 deg. is sufficient with proper PH maintained of the reaction mixture, usually alkaline adjusted using aqe.NH4OH.The solid complex separates out on heating ,further filtered to get desired product.
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Nitrogen in wheat
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The nitrogen available to the plant as ammonium salt. Amides decompose producing ammonia like urea & in soil ammonia form ammonium salts trans located into different parts of the plant parts. Amide nitrogen applied to wheat in what soluble amide form . Amide gets hydrolyzed by alkaline soil to liberate ammonia which will be made available to wheat crop.This is probable mechanism foe amide reactivity.
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How can I remove excess amine from these reaction products? I did the reaction which may formed mono and di adduct and also present some excess amine.
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You can prepare a mono adduct of amide from the reaction between lactone and ethylenediamine by heating one mole of lactone with half mole of ethylene diamine in ethanolic solution.
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I am doing an experiment functionalize CNT via 3 steps: oxidation, acyl-chlorination, and amidation. At step 2, carboxylated CNT was treated with a mixture of SOCl2 and DMF (20:1) at 70oC for 24h. Then the acyl-chlorinated CNT was centrifuged and washed with THF for 5 times before going to step 3. However, I suppose the COCl groups be moisture-sensitive and could easily be reversed to COOH groups when exposing to the atmosphere.
What is the method to treat the acyl-chlorinated CNTs without making the impact on COCl groups?
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Instead of doing centrifugation, carefully distill off the thionyl chloride right from the reaction. Then add a large (5-10x) excess of very dry amine/amine solution to the "crude", dry acyl chlorinated CNTs. You can also just add 1 eq of your amine along with a bunch of non-nucleophilic amine like triethylamine, you just need something to counteract the HCl that is leftover from the chlorination and forms during the amidation.
 After it reacts you can do your centrifugation, and the CNTs are never exposed to ambient air in reactive form.
Exposing COCl-CNT to air to wash and centrifuge them is pretty much going to instantly hydrolyze them. Even your THF probably will have enough water to kill it.
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Most the processes of amino-functionalization of CNTs include 3 steps: carboxylation, acyl-chlorination, and amidation. Why don't we directly do the amidation reaction of carboxylated CNTs with amines? Is it because carboxylated CNTs are less reactive, harsh condition, or low conversion?
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Dear Huy,
If you do direct reaction of a carboxylated CNT with an amine, your product will be the ammonium salt of the carboxylated CNT and NOT the amide. This is actually a neutralization of the carboxylic acid moiety (an acid) with amine (a base).
-COOH + NH3 gives   -COO- NH4+.
Hoping this will be helpful,
Rafik
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I want to know specific ring-opening mechanism.
Please link papers and explain how to synthesis linear amide.
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I am trying to couple Amino Peg azide with dendron having acid.
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If this EDCl is that water-soluble carbodiimide what i think, i am sure you can not. Methanol is quite good nucleophil, so you would get a methanol ester instead of your desired coupled amine and acid side chain.  If you have solution problem you can add some DMSO to the reaction mix (if i remember well) for example. And you need a proper  pH.
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I'm doing a reaction in formamide and I have managed to remove nearly all of the solvent by roto-vap.  Does anybody know any formamide azeotropes to allow me to remove the last traces of formamide? Any references would be greatly appreciated also
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Try with toluene (50%) and acetic acid (25%).
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I want to hydrolyse the -cyno group selectively into the Amide as well as Acid functionality, I have already tried in Basic madium but no positive result.
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You can hydrolyze -cyno group into the Acid using mineral acid by the procedure available in standard book like A Text book of practical Organic Chemistry by A.I. Vogel.
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i have tried alot to evaporate the excess thionyl chloride but it ruined the rotavab ! 
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You are removing exess  SOCl2 from your acid chloride so that SOClwill spoil your vacuum pump and environment, By using NaOH or KOH(base) in trap that will become salt  and farms solid in that trap, while doing this observe the solid may blokes the trap  
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I want to synthesize the orthoamino phenylboronic acid derivatives.
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i already tried the reaction but it is not going forward but when i did the reaction in opposite direction , i mean the carboxylic group instead of amine , the reaction is going forward with amine in other reactant. i dont understand why it is so ?
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I synthesised an amide compound from the reaction between (3-aminophenol and isophthaloyl chloride) in the presence of N,N'-dimethylacetamide as a solvent. After i washed the product with ice-cold deionised water several times to remove the generated HCl, and then recrystallised from hot ethanol and precipitated into ice-cold water again, i got a really pure product, and also a very high yield. However, i need an explanation for the mechanism.
Although I did not use any base to react with the HCl by product, to shift the reaction to product and make it irreversible, the reaction was successful. So what is a reason behind this?
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An amine reacts fast with an acid chloride. The HCl is possibly trapped by the solvent. The amide once formed will not reverse back in significant extent... It may hydrolise if the reaction conditions are not water-free.
What I think about the equilibrium, is that is driven to the products for 2 reasons:
1. Products are thermodinamically favorable
2. HCl is quenched by the large excess of the acetamide solvent.
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I am trying amide bond formation reaction using PyBOP.Will acidic workup work for the extraction of the compound? How can the PyBOP be removed?
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You can do acid and basic aqueous extractions, then wash with satd. NaCl, dry over magnesium sulfate, and use flash chromatography to remove any remaining PyBOP if necessary.
EDC/HOBt can be easier as everything can be removed through extractions.
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Like from N-phenyl benzamide to N,N-diphenyl benzamide or N,N-phenyl(benzyl)benzamide.
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Would a base like cesium carbonate be ok for you? on another hand have you thought at doing your synthesis the other way around, I mean: using diphenyl amine + the required acid chloride. Good luck.
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I am now trying to make amide linkage between primary amine and carboxylic groups. My amine is aniline derivative which is less reactive, so I use strong coupling agent TBTU / DIEA. But it gave bad yield. Does anyone have some recommendation about my case?
And I let my reaction happen in normal environment, not Nitrogen or Argon atmosphere. Does it cause serious affect when using TBTU/DIEA?
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Years ago, I was working on the commercial scale amidation of a substituted aniline.  If you are doing lab scale only, you might not change your procedure, but if you scale up commercially, this is probably the best way to go.   
In my reaction, I used pivaloyl chloride, though I suspect the chemistry will work well with any acid chloride.  Ordinarily, one would do the chemistry in an organic solvent, but the amine on the aniline is so reactive with the acid chloride that I was able to run the reaction using water as a solvent, and get near quantitative yields.  The product separated out as a beautiful white crystalline material, which was easily isolated in a centrifuge bag, and the waste stream was salt water with a little bit of aniline in it. 
Since your monomer is soluble in DMSO, I'm guessing that water would be a fine solvent as well. 
I ran my chemistry on a 1000 gallon scale, and it worked right every time. 
 
If you try this on your reaction and it works well for you, please let me know.  As a patent attorney, it's always nice to know my knowledge of chemistry is still relevant.