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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: orgostudent on April 17, 2008, 08:27:06 AM

Title: cyclohexanone reaction
Post by: orgostudent on April 17, 2008, 08:27:06 AM
what kind of reaction is this--

cyclohexanone + H2N-NH-Ph / catalytic H+

i have to draw the structure of the product from this reaction
Title: Re: cyclohexanone reaction
Post by: macman104 on April 17, 2008, 08:34:18 AM
Imine Formation (http://www.cem.msu.edu/~reusch/VirtualText/aldket1.htm)
Title: Re: cyclohexanone reaction
Post by: orgostudent on April 17, 2008, 08:47:08 AM
so the structure should have a carbon nitrogen double bond?
Title: Re: cyclohexanone reaction
Post by: macman104 on April 17, 2008, 09:06:43 AM
Yes.
Title: Re: cyclohexanone reaction
Post by: sjb on April 17, 2008, 09:48:18 AM
Well, the initial product might have a carbon-nitrogen double bond, but it may not be the final product.

I don't think hydrazone formation really needs acidic catalysis (based on my limited experience of 1 or 2 reactions and loads of imines, but I could be wrong)

How hard are you hitting the reaction? Something else may happen...

(edit: well, as macman104 has given a link to imine formation, I may as well play my card too, and show http://en.wikipedia.org/w/index.php?title=Fischer_indole_synthesis&oldid=158175672 )

S
Title: Re: cyclohexanone reaction
Post by: macman104 on April 17, 2008, 10:06:49 AM
edit: well, as macman104 has given a link to imine formation, I may as well play my card too, and show http://en.wikipedia.org/w/index.php?title=Fischer_indole_synthesis&oldid=158175672
I concede ;).  But somehow, I have this feeling orgostudent may not have learned fischer indole synthesis.
Title: Re: cyclohexanone reaction
Post by: AWK on April 17, 2008, 10:10:19 AM
Well, the initial product might have a carbon-nitrogen double bond, but it may not be the final product.

I don't think hydrazone formation really needs acidic catalysis (based on my limited experience of 1 or 2 reactions and loads of imines, but I could be wrong)

How hard are you hitting the reaction? Something else may happen...

(edit: well, as macman104 has given a link to imine formation, I may as well play my card too, and show http://en.wikipedia.org/w/index.php?title=Fischer_indole_synthesis&oldid=158175672 )

S


Rather tetrahydrocarbazole is formed
Title: Re: cyclohexanone reaction
Post by: macman104 on April 17, 2008, 10:18:09 AM
Yes, but the mechanism is that of the indole synthesis no?  The fact that a cyclic ketone results in the 3 ring structure doesn't change that fact does it?
Title: Re: cyclohexanone reaction
Post by: orgostudent on April 17, 2008, 10:46:55 AM
how about this....

C5H10-C=N-NH-Ph + H2O
Title: Re: cyclohexanone reaction
Post by: AWK on April 18, 2008, 01:01:18 AM
how about this....

C5H10-C=N-NH-Ph + H2O
Yes, but not in acidic media

Do you know story of discovery of this synthesis. Soon after discovery of phenylhydrazine, in Fisher lab during organic synthesis, students synthesised phenylhydrazone of pyruvic acid (CH3COCOOH). After crystallization from ethanol all except one got the needed colorless crystals of  phenylhydrazone. This (fortunate) student got deep blue powder which cannot be dissoved in water or ethanol. Fisher started conducting an investugation and found that the alcohol used for crystallization by this student was acidic (this student pures ethenol into bottle used prviously  to hydrochloric acid). And this investigated powder appeared to be the indigo.
Title: Re: cyclohexanone reaction
Post by: sjb on April 18, 2008, 03:27:48 AM
Thanks AWK, I didn't know that.

Just goes to show what with all the planned stuff that goes on these days and back before all the instrumentation we take for granted in the lab, a lot of stuff was truly discovery and very intelligent people working on fundamentals.

I wonder what people like Fischer, Perkin, Sabatier etc would make of the labs, the information exchange and everything else in modern chemistry today...

Something to ponder for the weekend, perhaps.

S
Title: Re: cyclohexanone reaction
Post by: AWK on April 18, 2008, 04:24:14 AM
Perkin discovered mauveine serendipitously because he did not use a pure aniline
Title: Re: cyclohexanone reaction
Post by: orgostudent on April 18, 2008, 08:27:00 AM
would it better if it was

C5H10-C=N-NH-
Title: Re: cyclohexanone reaction
Post by: AWK on April 18, 2008, 09:15:18 AM
would it better if it was

C5H10-C=N-NH-
This suggests one carbon atom is outside the ring
C6H10=N-NH-Ph will be better