[Harmeet]

Want to synthesise 4(5) hydroxymethyl imidazole picrate from fructose acc. to procedure of DarbY(1942).  i tried the reaction 7-8 times  acc to procedure. but not able to isolate picrate salt. I got cu-imidazole green color complex but after acidification with HCl and passing H2S gas and filtration of Copper sulfide ppt and boiling filtrate for 15 min when i added picric acid to filtrate yellow color sol formed but on cooling i got pptof comp having m.p 107°c (m.p of picric acid)rather than 203°c. Kindly help regarding sol for this problem.

[Arkcon]

Here's a reference to your process, and also a better procedure, see following the second procedure this improves your yield: https://archive.org/stream/OrganicSynthesesVolume24/OrganicSynthesesVolume24_djvu.txt

[Harmeet]

Dear Sir,

I m following same procedure of organic synthesis. But i got green colour filtrate after passing H2S gas. I dont understand where is mistake. Whether before adding Picric acid we have to neutralize HCl. Can this HCl interfere with formation of picrate. Kindly guide

[Dan]

procedure of DarbY(1942).

Journal? Page number? It helps if you provide enough information for us to find the document...

Are you following this procedure?

Org. Synth. 1944, 28, 64 link

[Harmeet]

Yes, I m following same procedure of Org. Synth, 1944, 28,64.
1.I want to know whether H2S is passed from sol under hot conditions or at room temp.
2. After passing H2S  gas from sol I got green color filtrate rather than light brown filltrate.
3. Before adding picric acd if there is need to neutralize  added HCl for passing H2S gas.
4. if there is need to neutralize HCl then which base should be used.


Kindly guide me.