December 15, 2019, 12:05:55 AM
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Topic: What reactant to use to make 5-hydroxypentanoic acid from 4-brmo1-butanol  (Read 317 times)

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Offline Nozon

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I want to make 5-hydroxypentanoic acid from 4-bromo-1butanol

But what other reactant would be prefered?
I have an option to either use Grignard carboxylation or nitrile as my second reactant.

What would be best to use to make it?

My idea would be a nitril (NaCN) to remove the alkyl halide and then hydrolyse it acid (To avoid deprotonate my alcohol)
Would it work or am I just hopeless at organic chemistry?

Offline chenbeier

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Yes this would work. Also you can protect the hydroxylgroup and make grignard on the bromine side and react it with formaldehyde.

Offline rolnor

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You mean carbondioxide, not formaldehyde?

Offline Nozon

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Yes this would work. Also you can protect the hydroxylgroup and make grignard on the bromine side and react it with formaldehyde.

How would i be able to protect my hydroxylgroup? Any suggestions on how? :) deprotonate it with a base?

Offline chenbeier

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Silyl, Ether, Ester,...

Offline rolnor

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If you deprotonate you can get ringclosure, a problem with the Grignard route is that you can get ringclosure of the final acid if you use a acid-labile protecting group. You could use a benzyloxymethyl group, this can be removed by hydrogenation and can be put on with mild base like triethylamine and benzyloxymethylchloride. The nitril-route is more convinient. I wonder why you want to do this, cant you buy the acid? Or hydrolyze the corresponding lactone?


Offline AWK

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AWK

Offline Nozon

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If you deprotonate you can get ringclosure, a problem with the Grignard route is that you can get ringclosure of the final acid if you use a acid-labile protecting group. You could use a benzyloxymethyl group, this can be removed by hydrogenation and can be put on with mild base like triethylamine and benzyloxymethylchloride. The nitril-route is more convinient. I wonder why you want to do this, cant you buy the acid? Or hydrolyze the corresponding lactone?


It is for my organic exame and I've read my whole pensum, but there has been no introduction with any reaction alike. So I believe it's a question made in order to prove the students creativity and reason behind the final choice.

But thanks  - made alot of sense. I'll keep that in mind. 

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