03-06-02 21:05
No 277965
The equilibrium constant for the formation of a hemiacetal from an alcohol and a ketone is 10^(-2)
The ratio of methanol to ketone in all of the variations is big though. Between 20-40:1
The question is does this reaction compete with the reductive amination? I dont know the rate and equilibrium of the amination, and i would love it if somone could point out somwhere to find the mechanism and such for it. But it seems like this would be a reason to use minimal solvent or a differnt one altogether.
Cause its so fun!
(Chief Bee)
03-06-02 21:17
No 277966
As the ketone reacts with the amine, forming the imine (and then is irreversibly reduced), the equilibrium shifts towards the ketone. Hemiacetal formation is no problem.
(Stranger)
03-06-02 21:37
No 277971
UHhhh, sorry i dont understand what you are saying. The imine to amine in irreversable so your saying that once its formed the game is over for that molecule. And for the hemiacetal since its reversable will eventualy become the amine and say there. Or the hemiacetal wouldnt form?
And what do you mean by saying the equilibrium shifts towards the ketone?
Cause its so fun!
(Chief Bee)
03-07-02 03:20
No 278121
The hemiacetal formation is reversible, just like the imine formation, but the imine reduction is irreversible. Any hemiacetal that forms, will hydrolyze back to the ketone as the amine is formed. Your interpretation is correct.
Illustration:
Hemiacetal <-> Ketone <-> Imine -> Amine
(Stranger)
03-07-02 06:45
No 278224
ahhh the hemiacetal <-> ketone eqilibrium is shifted towards ketone as ketone <-> imine -> amine reactions progress. gotcha, thanks.
Cause its so fun!
(Hive Bee)
03-07-02 09:28
No 278289
book shows six interesting ends to resolution of dl-analine
1]dl-ch3ch[nh2]co2h
2]dl-ch[nhcoch3]co2h
3]h2nch[co2h][ch3]
4]hc[co2h][ch3]nhcoch3
4] shown in differnt structure .....ch3ch[nh-[c=o]ch3]cooh
5]ch3ch[n=c[oh][ch3]]cooh
6]ch3ch[n=c[ch3]oc=o]
melt point mentioned for all as well MW
1 is n acetyl derivative
2 in weak alk sol acylase um anyways they protect with coch3
um n-acetyl d analine
.......anyways it is a little hard to type set
I can read? I know there is something usefull in these books i procure or i wouldent go back year after year and hagle these folks cccause i am nearly flat broke they allways finally give in to basicially giving it to me for almost nothing.
(Master Searcher)
03-07-02 12:23
No 278343
There is no such thing as dl-analine. Aniline has only one form and dl-alanine exists.
http://www.geocities.com/dritte123/PSPF.