I am trying to do an amide with a benzoic acid (substituted on meta position with alkyl) and a aminopropanol. I am looking for the best conditions with EDC, HOBt (temperature, equivalent, time, etc)
If you don't have to bother for stereochemistry, need not to use HOBt. In case if you are using, 1 or 1.02 equivalent of HOBt is enough. Dissolve in minimum amount of DMF if you prefer to use other solvent for reaction like DCM or THF. The reaction can be performed at room temperature over night. After adding all the reagents check for the pH to be 8.
If you dont need to care any risk of loss of configuration, make a chloride of your COOH, by using either SOCl2 (under ultrasound this gaves your chloride in 100% yield, within 30 min) or a fluoride , by employing one of the many fluorinating agents commercially available ((CN3)F3 or TFFH-OXYMA).
Both of those steps are followed by the acylation leading to your product in high yields.
In peptide synthesis those methods are avoided for the high risk of racemization via 5H oxazolone formation, which brings into register, the active esters mediated coupling protocols.
If this is even your case, dissolve your acid in DCM (plus some dmf if not soluble), and add 1.2 eq of HOBT (it becomes a suspension for the low solubility of HOBT in such solvent), followed by EDC (after 5 min), and your amine.
The formation of the active ester is highlighted by your suspension becoming colorless upon the EDC addition.
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