More chemistry help please!! (FAO all you chemistry geniouses out there)

Ok guys..

What would you get if you reacted (s)-2-bromobutane with KCN and DMF??

also..

What would you get if you reacted THAT product (i.e the product formed in the first reaction) with H3O+ and a little heat??

Thanks guys xx

Reply 1

charco

Study Forum Helper

This reaction is nucleophilic substitution (the DMF is just the solvent) of the halogenoalkane by the cyanide ion to give the nitrile - CH3CH(CN)CH2CH3

there will be two products for the second part depending on the ferocity of the hydrolysis conditions. Firstly the amide is formed and this in turn hydrolyses to the carboxylic acid

CH3CH(COOH)CH2CH3 or better written CH3CH2CH(CH3)COOH - 2 methyl butanoic acid

Reply 2

Schroedinger's Pandora

I knew the reaction would go somehere along those lines, but thank you for you help!!

Just one more thing..

say you reacted the (s)-2-bromobutane with Mg and dry ether?? (as the solvent)?

or if you reacted the (2)-2-bromobutane with NaOH and H2O??

I'm designing an exp but I'm not confident of my abilities :s-smilie:

Can anyone help?? (feeling a little dumb right now)

Reply 3

charco

Study Forum Helper

Magnesium forms a Grignard reagent of the form R-Mg-X this is stable in ether but then is usually reacted with other things to form a variety of products

NaOH in aqueous is nucleophilic substitution of the X by an OH group making (in this case) a secondary alcohol

NOTE: This last one is such a standard reaction that it is not a case of feeling dumb - it's a case of not wanting to look it up - get a life!

Reply 4

charco

Study Forum Helper

You are doing reactions of haloalkanes - the first reaction of haloalkanes that appears in ANY textbook at A' level is nucleophilic substitution using sodium hydroxide. To find this reaction you simply look up the section on haloalkanes -index useful here! (or halogenoalkanes in some texts) and find sodium hydroxide - understanding it is another thing, but actually finding the product of the reaction is not exactly rocket science.
... and I'm sorry if I was a little harsh.