Aldehydes and Ketones - major help needed

Arghh this homework is KILLING ME! I have been trying to do it for soo long.. its one of those annoying stupid really hard questions that would NEVER come up in the actual exam. Please please help its due tomorrow!!!!!!

1. Carvone is the main flavouring in Spearmint Oil (Diagram)

a) Draw the structure of the product obtained when carvone reacts with:

i) 2,4 DNPH
ii) Bromine

b) Explain why carvone does not react with ammonical silver nitrate
This is Tollen's right? I'm guessing if it doesnt react, it must be a ketone as only aldehydes react with Tollen's so I think this is okay

The rest of that question is about optical activity which is fine so I'll skip to question 2.

2) Beta-ionone occurs in oil of violets and is used as a fragrance. Its structure is: Click here

a) Would this molecule exhibit optical activity?
b) Could this molecule exhibit geometric isomerism?
c) Give the structure of the product formed when Beta-ionone reacts with:

i) HBr
ii) 2,4 DNPH
iii) NaBH₄ in ethanol at room temp

d) Would Beta-ionone have any reaction with ammonical silver nitrate?
e) Would Beta-ionone give a positive result when the iodoform test is carried out?

PLEASE if anyone can help, I will owe you so much and theres some rep in it for you.. please please :redface:

Reply 1

rupalini

Pleasee?? Anyone?

Reply 2

NeilosRobbos

1. Carvone is the main flavouring in Spearmint Oil (Diagram)

a) Draw the structure of the product obtained when carvone reacts with:

i) 2,4 DNPH << Forms 2,4-dinitrophenylhydrazone, not sure of the organic structure
ii) Bromine << Will eliminate the C=C bonds

b) Explain why carvone does not react with ammonical silver nitrate
This is Tollen's right? I'm guessing if it doesnt react, it must be a ketone as only aldehydes react with Tollen's so I think this is okay << Correct

The rest of that question is about optical activity which is fine so I'll skip to question 2.

2) Beta-ionone occurs in oil of violets and is used as a fragrance. Its structure is: Click here

a) Would this molecule exhibit optical activity? << Nope, there is no chiral carbon
b) Could this molecule exhibit geometric isomerism? << I guess this means like cis/trans isomerism, so yes, as there is C=C bonds with large/small groups on both carbon atoms.

c) Give the structure of the product formed when Beta-ionone reacts with:

i) HBr << Again eleminates c=c bonds, there's lots of different isomers of this however.
ii) 2,4 DNPH << It's an aldehyde, so it goes to 2,4-dinitrophenylhydrazone again.
iii) NaBH4 in ethanol at room temp << Reducing agent, so =O turns into an -OH and a H gets added to the C accordingly.

Double check some of it. Hope that helps.