Hello everyone,
I hope you are well. I'm following the procedure described in Synthesis 1986, 4, 282 (DOI: 10.1055/s-1986-31587) and I’m having difficulties during the recrystallisation step of 4a (the azide intermediate). I was wondering if anyone is familiar with this and I really appreciate any insights that anyone could give me have as I suspect I may be overlooking a key detail or misinterpreting the protocol. I started by refluxing the crude with diethyl ether and I noticed some solid didn't solubilize at all. I filtered off this solid and analysed (probably the sulfoxide resulting from partial oxidation). Then I put the filtrate in an ice-bath and nothing ppt. Then I concentrated the organic layer and analysed - my product was there. I confirmed the product 4a after purification by prep-HPLC, however, I will need this compound in high amount, so the recrystallisation is really important. I was wondering if anyone has experience with this and could give me any insight? Thanks in advance for your time.