Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: lissydoll206 on July 21, 2006, 11:54:24 AM
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In this reaction I have figured out 2 of the 3 products that form. Is the 3rd product a carboxylate? If so, what does it look like? Thank you!
I have attached the reaction and what I think the other two products are below.
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How did you figure out two of the products without drawing a mechanism?
What might hydroxide ion do to this compound?
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I had drawn out the mechanism on paper using my text but I was having trouble figuring out what the 3rd product would be... I will draw out the mechanism and what I think happens, but it will take me a little bit to draw it out...
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Yah amide and carboxylic acid salt are visible product but what further ??? Alfa hydroxylic acids are not most stable but dehydrogenation seems to me not the hint,, Do you think about possible sodium alcoholat formation: -OH + NaOH -->O:-Na+ may be in a-hydroxylic acids this is much stable also if work up with conc. NaOH solution...
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I'm pretty sure that the third product is cyclohexanecarbaldehyde. Strongly basic conditions can deprotonate the cyanohydrin (the alpha-hydroxynitrile), and this deprotonated cyanohydrin is in equilibrium with its aldehyde plus cyanide.
O- CN R
\ / \
C <==> C=O + CN-
/ \ /
R H H
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Yes this is possible reaction, but as its equilibrium one and the base is in excess then furthen alkaline hydrolyze of CN group to amide and carboxylate can't be avoid. Also do you think the formed cyclohexanal may proceed some aldol condensation in the basic media and what product(s) that ?
Really complicated case :)
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I doubt cyclohexanecarbaldehyde would do a base-catalyzed aldol condensation since the enolate would be unstable due to a negative charge on a tertiary carbon.
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Well i know that Br2 readily react with cyclohexanecarbaldehyde as CH-CHO group become C(Br)CHO this is
1-bromocyclohexanecarbaldehyde. This reaction is adiition of Br2 to enolate form of cyclohexanecarbaldehyde so it exist pretty well though i also think aldol reaction is not most likely most because of some steric hindrance...Do you thin the cyanhydrine structure at which have CH(OH)CN group and thus CH is much acidic then C:-Na+ may be formed as well ???
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Interesting question. I couldn't find any pKa values for cyanohydrins, though I suspect the pKa for the C-H bond on CH(OH)CN would be higher than the O-H bond.
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It's sure that this CH is acidic bond but i couldn't find its pKa too...It's some unlikely for me aqueous NaOH to exchange this CH bond in predominant but some equilibrium will occur with sure.
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I just want to direct everyone's attention to the benzoin condensation (http://www.organic-chemistry.org/frames.htm?http://www.organic-chemistry.org/namedreactions/benzoin-condensation.shtm).
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Nice example for CH acidity of cyanhidrines. But as this is aliphatic cyanhidrine it's unlikely such condensation to occur. Though i have some memory about some multicomponent reactions between aliphatic aldehydes with aliph cyanhidrines, which i'll try to find :)