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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: CHM on July 01, 2006, 01:32:32 PM

Title: 2-hydroxybenzoyl chloride synthsis
Post by: CHM on July 01, 2006, 01:32:32 PM
hi
I want do the reaction of 2-hydroxybenzoic acid and thionyl chloride,  to get  2-hydroxybenzoyl chloride any body can help me the steps or procedure for the synthesis?
Title: Re: 2-hydroxybenzoyl chloride synthsis
Post by: Morphic flip on July 02, 2006, 11:31:05 AM
The thionyl chloride will substitute the OH group with chlorine.
Take care!
Title: Re: 2-hydroxybenzoyl chloride synthsis
Post by: HP on July 02, 2006, 11:50:50 AM
First you should protect the OH group of salicilic acid by acetylation with Ac2O to acetylsalicilic acid (aspirin) as i remember :) Then you may convert COOH group to COCl by reaction with thionil chloride or PCL5. If want OH be further free and available you must simply hydrolize it but this after you react COCl with what you want. It seem to me imposible to deprotect OH without react COCl first (also COCl will react with OH to form ester) but this is not problem if use the so protected aduct for synthesis...
Title: Re: 2-hydroxybenzoyl chloride synthsis
Post by: CHM on July 02, 2006, 02:18:14 PM
I tried to make the reaction accoriding to similar compound the reaction was 4-flouro-2-hydroxy benzoic acid with thionyl chroide and they get the 4-flouro2-hydroxybenzoyl chloride.
this is my refr.
http://www-bio3d-igbmc.u-strasbg.fr/~podjarny/zandt_et_al.pdf
when i made it i get 5% yeild from 2-hydroxy benzoyl chloride.
actully i want to react  2-hydroxy benzoyl chloride with solid azo phenol. my problem is N=N decompose with H2SO4 when i make the reaction with 2-hydroxybenzoic acid and aceton as solvent. so i trid to use acid chloride instead of the acid ,what can i do to make my reaction.
Title: Re: 2-hydroxybenzoyl chloride synthsis
Post by: HP on July 02, 2006, 02:30:47 PM
Again it seems imposible for me the existence of unprotected hidroxy benzoylchloride compound you desire to..I cant understand whats the reaction with diazo compound you want to proceed, may be you mean reducing it to amine and then amidation with the RCOCl? If so it;s 100% working reaction Shotten-Bauman type :)
Title: Re: 2-hydroxybenzoyl chloride synthsis
Post by: CHM on July 02, 2006, 03:07:16 PM
 :)thank u. do you have a refrece or the idea to synthesis acid chloride after make asprine and mak the hydrolysis? becuse i want to react the OH group of the azo cpmpound with the acid chloride 
Title: Re: 2-hydroxybenzoyl chloride synthsis
Post by: HP on July 02, 2006, 03:24:07 PM
No, i dont have reference. The idea for making COCl of aspirin is as i described in my prev post. Some hint i can give you is ading some organic base as N(Et)3 or pyridine when you further react the acylchloride of aspirin with OH azo compound, for acepting the HCl formed. You should find the proper solvent for both azo-compound and other, though if the azo compound is as some salt it seems to not be very soluble in common organic solvents but i may mistake it as you have aromatic subst...Also its possible heterogenic reaction too. Thats all i can help you by this time :)
Whish you success!