# Molecules with more than 1 functional group

I need some help naming compounds with more than 1 functional group. Here are some examples:

• A 4-carbon alkane with an aldehyde and a ketone for both the ketone being right next to the aldehyde and the ketone and aldehyde having 1 carbon in between.

• A 5-carbon molecule with an $\ce{C=C}$ double bond at carbon number 2 and a $\ce{C#C}$ triple bond at $\ce{C}_4$ (maybe it is the reverse)

I think that for the one with a double bond and a triple bond that the triple bond gets highest priority and so it would be pent-4-en-2-yne but I am not sure about it.

• Mind taking look at Function group priroty table and example given in this pdf? This might solve your problem! – ashu Jul 31 '14 at 12:55
• ketone has lower priority than aldehyde. Okay that makes sense since OH has higher priority than C-C and that is basically priority-wise what ketones and aldeydes are. But why does the double bond have priority over the triple bond? Surely there are some where the triple bond is lower than the double bond, in fact I know so. Is it just that E comes before Y and that in the actual numbering you number it from the carbon closest to the triple bond? – Caters Jul 31 '14 at 14:37

There are some priority rules about naming compounds with more than 1 functional group.

• Aldehyde has higher priority than ketone (I don't know why but I think it is because of aldehyde always take place at the end of carbon chain)
• Alkene has higher priority than alkyne, because -ene suffix comes before -yne