[revathikala]

Hi,
Iam working on crownethers preparation,but i have lot of doubts in preparation of crown ethers.In the preparation of crownethers iam facing the solubility problem during the reaction.I am using dry THF as a reaction medium & continued the reaction for 21hrs.At the middle of the reaction total Dry THF evaporated & the total reaction mixture becomes solid because of evaporating Dry THF.Starting material of my reaction is tetrahydroxy compound & iam preparing dicrown compound from this.Please suggest any reaction medium & information on crownethers preparation.

My reaction is as follows
        MY starting material is symmetrical tetra hydroxy compound ,I want to
prepare bis15-crown-5 compound.For this preparation of dicrown i did reaction between tetrahydroxy compound & TEG ditosylate in presence of Dry THF & NaH under nitrogen presence.But the reaction is not going on  & i faced So many problems.Thats why Plese suggest any reaction or medium or conditoinsthat are used during the reaction to forward my step for preparation of dicrown.

thanking you.

[AWK]

There are many crown ethers, and they need different reaction conditions for synthesis. Usually you use a known procedure for a specific crown ether, and it should be work. Just read it carefully.

Using your secret data nobody can help you. Dicrowns may be much more difficult for synthesis. There is a bulk of literature on this subject.

[DrCMS]

How are you carrying out the reaction, conditions and equipment?
Why does your THF evaporate?

[agrobert]

You should cover your reaction so it doesn't evaporate.  Keep it under positive pressure of Argon or Nitrogen.

[revathikala]

SIR ,i gave in detail of my reaction .see once & say any suggestion

[AWK]

As I know, tosylates are used for reactions with amines mainly.

For synthesis you probably need a very diluted solutions.

Are you sure you use a tetrahydroxycompound?