Hello fellow researchers,
I'm tryinig to synthetize the followed molecule and it seems like either i haven't obtained it or in really low quantity whereas it is supposed to be a total reaction.
I'm wondering what could go wrong since the synthesis is pretty simple.
you must carried out above reaction in one step as:
NaH (1.5eq) + R-OH + R-Br (1.5eq) in DMF at room temperature for 24 h.
There is a possibility the quinone could be reduced to the diphenol. The first thing I will check is the quality of the NaH, especially if the starting material is recovered
a) Initially wash NaH with dry pentane or hexane first in order to remove the mineral oil. Secondly check the quality of NaH.
Thank you all for your kind answers.
Ranvijay Pratap Singh Isn't that better to first deprotonate the hydroxy function before adding the R-Br? Why would you use DMF? I heard DMF could do some reaction with NaH. And DMF will be harder to evaporate. Is that about solubility?
Eugene Yang Ok the quinone reduction is an interesting hypothesis, how would you check NaH quality? The NaH dispersion is dark grey as it was when i bought it. I obviously have reactant remaining.
Kachapur Arunkumar What is the purpose of removing mineral oil?
Something i'm wondering is could the AQ- form be insoluble in THF so the nucleophilic substitution wouldn't occur?
Why do you need to use NaH? I would try in an one pot procedure, in THF as hell, but using a bulky (or non nucleophilic base) instead. Make sure your THF is really dry.
Good luck
It is often the seemingly straight forward reactions that give the most problems. What is the pKa of the acetylenic proton which may be acidic enough to deprotonate with NaH. I would suggest dry K2CO3 in dry MeCN (or THF) and add 5-10% (n-Bu)4NI.
I tried an aromatic OH alkylation using K2CO3 in DMF at room temperature to 60 C and was successful.
You can follow the following link
https://www.organic-chemistry.org/protectivegroups/hydroxyl/allyl-ethers.htm
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