Sciencemadness Discussion Board

Need help on amino alcohols

Steam - 30-8-2014 at 22:10

I am currently trying to synthisize 1Amino-1ethanol to be chlorinated so I can use it in a grignard by Chlorinating the OH group. Unfortunately I have no idea how to synthesize it. I am thinking adding ammonia to acetyl Chloride, then using LAH to reduce the =O back into an OH group. However I would really like to avoid LAH if I can. Any help and thoughts is appreciated!
I have an image of the molecule I am after below. (note: I know I spelled ethanol wrong! It is 2 AM when I am posting this.)



1amino-1eathinol.PNG - 3kB

Paddywhacker - 30-8-2014 at 22:20

That compound would be unstable at STP. It would give off ammonia to form acetaldehyde.

unionised - 31-8-2014 at 01:18

And the ammonia would react with the acetaldehyde to make an imine.

And, if you could make it, you couldn't turn it into a Grignard reagent because of the amino group.
And if you could get that stuff and convert the OH to Cl, the chloro amine would polymerise into a mess.

What are you actually trying to make?
Because there's got to be a better way to do it.

Steam - 31-8-2014 at 13:20

This is the molecule I am ultimately after. R1 is a straight chain alkane.

20140831_171717.jpg - 1.7MB

kavu - 31-8-2014 at 23:46

There are many perfectly good alpha-amination reactions, consider using them. This nucleophilic amine addition of yours doesn't work as previously stated. The motif looks awfully much like it belongs to phenethylamine class, though...

[Edited on 1-9-2014 by kavu]

DJF90 - 1-9-2014 at 00:24

If you're not after chirality, perhaps you could add nitroethane to an appropriate acyl(+) synthon. Reduction of the nitro group to an amine should be straightforward.

Steam - 1-9-2014 at 10:03

Got it thank you. And kavu, in case you were wondering I am not after anything that would really fall into a phenylethylamine (drug) class of molecule. Unfortunately we live in a day where as soon as you even mention synthesizing something with the words "phenyl" and "amine" you get a lot of suspicion of being a meth cook in some turgid lab in the basement of some dilapidated house. Shame.
I am going to be atraching a butane group in for R1 and I was going to attach diphenylmethanol in on the ketone group. However like was mentioned before grignard do not work with compounds that have amines in them.
DJF90, I will probably gave do do just that and will have to take care of attaching the diphenyl group before dealing with amination.

DJF90 - 1-9-2014 at 11:17

Knoevanagel condensation between valeraldehyde (pentanal) and nitroethane will give a nitroalkene which can undergo michael addition with Ph2CH(-) (I assume this is what you meant by "diphenylmethanol group). Reduction of the aliphatic nitro group then gives the desired product (which you've not actually drawn...)

Because the product of the Michael addition is more acidic than the Ph2CH(-), you'll have to take care which way around you do the addition and use an excess of the appropriate reagent (but I'll leave you to work these finer details out).

[Edited on 1-9-2014 by DJF90]