I nearly always used 1 eq. of powdered KOH added to a DMF solution of the phenol (adding the phenol first, so my KOH didn't hydrolyse the DMF too badly) and stirred until completion. KI is a good idea. Once I tried NaOH instead and got almost zero conversion.
i had to use 2 equivalents as it reacts twice as it's a catechol and i wanted to alkylate both OHs, i did do the reaction in DMF using potassium carbonate once i got the conditions locked down, although it improved the rate, the DMF was very hard to remove and would not scale well so i stuck with MeCN
I nearly always used 1 eq. of powdered KOH added to a DMF solution of the phenol (adding the phenol first, so my KOH didn't hydrolyse the DMF too badly) and stirred until completion. KI is a good idea. Once I tried NaOH instead and got almost zero conversion.
i had to use 2 equivalents as it reacts twice as it's a catechol and i wanted to alkylate both OHs, i did do the reaction in DMF using potassium carbonate once i got the conditions locked down, although it improved the rate, the DMF was very hard to remove and would not scale well so i stuck with MeCN
K2CO3 is the strongest base of the 3 (and also the most soluble), and for this reaction it might just be a case of goldilocks syndrone. I bet cesium carbonate would work nicely too , its an even stronger base with some very unique properties.
ahah, i knew this would come up, we have tried Cs2CO3, however we cannot use it as we are making caesium selective stuff, so we cannot have Cs contamination.
I used 3.5 eq of 2-(2-chloroethoxyethanol) and 5.6 eq of base (for carbonates) and 2 eq for hydroxides (as excess hydroxide would cause ester hydrolysis.
K2CO3 is the strongest base of the 3 (and also the most soluble), and for this reaction it might just be a case of goldilocks syndrone. I bet cesium carbonate would work nicely too , its an even stronger base with some very unique properties.
ahah, i knew this would come up, we have tried Cs2CO3, however we cannot use it as we are making caesium selective stuff, so we cannot have Cs contamination.
I used 3.5 eq of 2-(2-chloroethoxyethanol) and 5.6 eq of base (for carbonates) and 2 eq for hydroxides (as excess hydroxide would cause ester hydrolysis.
Its curious that you're working on catechols at the same time as our other poster, now I see why you offered the benzoate as a substrate.
Anyways, when you say yield, do you mean conversion too? Catechols are unstable under basic conditions, so if they don't react quickly, they will oligomerize and produce crap via quinones that give both radical and Michael addition. I would expect all your carbonates to work somewhat, TEA to not work at all (too weak a base) and the metal hydroxides to produce chloro elimination and ester hydrolysis as you mentioned. What were the equivalents of base and 2-(2-chloroethoxy)ethanol? Were all these bases fully solubilized?
K2CO3 is the strongest base of the 3 (and also the most soluble), and for this reaction it might just be a case of goldilocks syndrone. I bet cesium carbonate would work nicely too , its an even stronger base with some very unique properties.
Its curious that you're working on catechols at the same time as our other poster, now I see why you offered the benzoate as a substrate.
Anyways, when you say yield, do you mean conversion too? Catechols are unstable under basic conditions, so if they don't react quickly, they will oligomerize and produce crap via quinones that give both radical and Michael addition. I would expect all your carbonates to work somewhat, TEA to not work at all (too weak a base) and the metal hydroxides to produce chloro elimination and ester hydrolysis as you mentioned. What were the equivalents of base and 2-(2-chloroethoxy)ethanol? Were all these bases fully solubilized?
K2CO3 is the strongest base of the 3 (and also the most soluble), and for this reaction it might just be a case of goldilocks syndrone. I bet cesium carbonate would work nicely too , its an even stronger base with some very unique properties.
Also, sometimes you can just add a bunch of water to a DMF reaction and the product that is organosoluble will crash out, then you can just filter and rinse the solid with water a few times. Is your product a solid or an oil with those oligo PEGs?
it's an oil> i diluted lots with water and added some LiCl to complex the DMF. extracted a few times into DCM, then washed a few times with water. there was still loads of DMF in my product, i did manage to rotorvap of most of it but i couldn't get all of it out.
Also, sometimes you can just add a bunch of water to a DMF reaction and the product that is organosoluble will crash out, then you can just filter and rinse the solid with water a few times. Is your product a solid or an oil with those oligo PEGs?
it's an oil> i diluted lots with water and added some LiCl to complex the DMF. extracted a few times into DCM, then washed a few times with water. there was still loads of DMF in my product, i did manage to rotorvap of most of it but i couldn't get all of it out.
KOH in DMF for Williamson ether is an old standby, maybe give it a check. Should be able to remove DMF by just dumping in DCM and washing with water 4-5 times.
Also, sometimes you can just add a bunch of water to a DMF reaction and the product that is organosoluble will crash out, then you can just filter and rinse the solid with water a few times. Is your product a solid or an oil with those oligo PEGs?
KOH in DMF for Williamson ether is an old standby, maybe give it a check. Should be able to remove DMF by just dumping in DCM and washing with water 4-5 times.
Also, sometimes you can just add a bunch of water to a DMF reaction and the product that is organosoluble will crash out, then you can just filter and rinse the solid with water a few times. Is your product a solid or an oil with those oligo PEGs?
I nearly always used 1 eq. of powdered KOH added to a DMF solution of the phenol (adding the phenol first, so my KOH didn't hydrolyse the DMF too badly) and stirred until completion. KI is a good idea. Once I tried NaOH instead and got almost zero conversion.
I nearly always used 1 eq. of powdered KOH added to a DMF solution of the phenol (adding the phenol first, so my KOH didn't hydrolyse the DMF too badly) and stirred until completion. KI is a good idea. Once I tried NaOH instead and got almost zero conversion.
i had to use 2 equivalents as it reacts twice as it's a catechol and i wanted to alkylate both OHs, i did do the reaction in DMF using potassium carbonate once i got the conditions locked down, although it improved the rate, the DMF was very hard to remove and would not scale well so i stuck with MeCN
i had to use 2 equivalents as it reacts twice as it's a catechol and i wanted to alkylate both OHs, i did do the reaction in DMF using potassium carbonate once i got the conditions locked down, although it improved the rate, the DMF was very hard to remove and would not scale well so i stuck with MeCN
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ahah, i knew this would come up, we have tried Cs2CO3, however we cannot use it as we are making caesium selective stuff, so we cannot have Cs contamination.
I used 3.5 eq of 2-(2-chloroethoxyethanol) and 5.6 eq of base (for carbonates) and 2 eq for hydroxides (as excess hydroxide would cause ester hydrolysis.
ahah, i knew this would come up, we have tried Cs2CO3, however we cannot use it as we are making caesium selective stuff, so we cannot have Cs contamination.
I used 3.5 eq of 2-(2-chloroethoxyethanol) and 5.6 eq of base (for carbonates) and 2 eq for hydroxides (as excess hydroxide would cause ester hydrolysis.
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Anyways, when you say yield, do you mean conversion too? Catechols are unstable under basic conditions, so if they don't react quickly, they will oligomerize and produce crap via quinones that give both radical and Michael addition. I would expect all your carbonates to work somewhat, TEA to not work at all (too weak a base) and the metal hydroxides to produce chloro elimination and ester hydrolysis as you mentioned. What were the equivalents of base and 2-(2-chloroethoxy)ethanol? Were all these bases fully solubilized?
K2CO3 is the strongest base of the 3 (and also the most soluble), and for this reaction it might just be a case of goldilocks syndrone. I bet cesium carbonate would work nicely too , its an even stronger base with some very unique properties.
Anyways, when you say yield, do you mean conversion too? Catechols are unstable under basic conditions, so if they don't react quickly, they will oligomerize and produce crap via quinones that give both radical and Michael addition. I would expect all your carbonates to work somewhat, TEA to not work at all (too weak a base) and the metal hydroxides to produce chloro elimination and ester hydrolysis as you mentioned. What were the equivalents of base and 2-(2-chloroethoxy)ethanol? Were all these bases fully solubilized?
K2CO3 is the strongest base of the 3 (and also the most soluble), and for this reaction it might just be a case of goldilocks syndrone. I bet cesium carbonate would work nicely too , its an even stronger base with some very unique properties.
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it's an oil> i diluted lots with water and added some LiCl to complex the DMF. extracted a few times into DCM, then washed a few times with water. there was still loads of DMF in my product, i did manage to rotorvap of most of it but i couldn't get all of it out.
it's an oil> i diluted lots with water and added some LiCl to complex the DMF. extracted a few times into DCM, then washed a few times with water. there was still loads of DMF in my product, i did manage to rotorvap of most of it but i couldn't get all of it out.
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Also, sometimes you can just add a bunch of water to a DMF reaction and the product that is organosoluble will crash out, then you can just filter and rinse the solid with water a few times. Is your product a solid or an oil with those oligo PEGs?
Also, sometimes you can just add a bunch of water to a DMF reaction and the product that is organosoluble will crash out, then you can just filter and rinse the solid with water a few times. Is your product a solid or an oil with those oligo PEGs?
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