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Help with retrosynthesis :o

Im trying to figure out a retrosynthetic pathway to the following molecule (http://www.chemicalbook.com/ProductChemicalPropertiesCB81511066_EN.htm) but keep getting stuck :frown:

Any ideas?

Reply 1

woods.vanessa

My bad the picture in the link I know how to make but the molecule I actually want to make has an extra carbon in the chain so Im stuck on how to add it or whether I need a whole new synthesis :s-smilie:

For this product I started with benzene, brominated then added to ethylene oxide, then SOCl2 to get rid of the OH then added Mg and CO2 to add the ester group then added NH3 to add the amine group!

Reply 2

woods.vanessa

Just realised that synthesis doesnt actually work haha so confused

Reply 3

Acruzen

usually the best way to increase the number of carbons in the chain is to react the molecule with a cyanide ion

Reply 4

woods.vanessa

Original post by Acruzen

usually the best way to increase the number of carbons in the chain is to react the molecule with a cyanide ion

I think I can use the Arndt Eistert mechanism too but I cant think of how to add the bromine thats on the benzene ring? Can I just brominate twice and hope the reactants only react with one of the bromines?

Reply 5

BJack

Original post by woods.vanessa

Why do you need to brominate twice? I'd stick bromine on at the end — it would surely be strongly p-directed over ortho for steric reasons.

Reply 6

woods.vanessa

Original post by BJack

Why do you need to brominate twice? I'd stick bromine on at the end — it would surely be strongly p-directed over ortho for steric reasons.

But the bromine is meta in relation to the group attached not para :s-smilie:

Reply 7

BJack

Original post by woods.vanessa

But the bromine is meta in relation to the group attached not para :s-smilie:

Not in the diagram you've given us. It's got a 1,4-disubstituted benzene, i.e. the Br and R-group are para to each other.

Reply 8

woods.vanessa

Original post by BJack

Not in the diagram you've given us. It's got a 1,4-disubstituted benzene, i.e. the Br and R-group are para to each other.

Oh right I see sorry no worries Ill ask at uni!
Thanks for the help though :smile:

Reply 9

illusionz

Original post by Acruzen

usually the best way to increase the number of carbons in the chain is to react the molecule with a cyanide ion

If you replace 'usually' with 'one way' I would agree with you. There are many more common methods.

Original post by woods.vanessa

Im trying to figure out a retrosynthetic pathway to the following molecule (http://www.chemicalbook.com/ProductChemicalPropertiesCB81511066_EN.htm) but keep getting stuck :frown:

Any ideas?

Does the molecule you're trying to propose a synthesis of have to be the (S) stereoisomer or can it be racemic? Chiral purity makes things significantly more difficult.