How can you tell there is unsaturation? (example)

[Forkit]

2,2-dimethyl-4-propyl-5-cyclopenytylnonane

^^ How does one find out if there is unsaturation in the above formula?

Thanks.

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[Phlame217]

Follow the (2N+2) rule. N is the number of carbons and when plugged into that formula should yeild the number of hydrogens on a saturated alkane. If there are less hydrogens, then its unsaturated. Also alkenes or or whatnot are also obvious signs of unsaturated.

 

[ksmi117]

Also, if there is "cyclo"anything in the formula, its unsaturated, much like if it is an alkene or alkyne.

 

[Forkit]

Follow the (2N+2) rule. N is the number of carbons and when plugged into that formula should yeild the number of hydrogens on a saturated alkane. If there are less hydrogens, then its unsaturated. Also alkenes or or whatnot are also obvious signs of unsaturated.

How can i determine how many units of unsaturation?

Thanks everybody!

 

[ksmi117]

Units of unsaturation = (2*number of carbons + 2 - number of hydrogens/halogens) / 2

Benzene, for example -> (2*6 + 2 - 6) / 2 = 4

3 units are due to the double bonds and the other is due to the ring

 

[Forkit]

So, in the example in the original post:

19 carbons
24 hydrogens

Units = [(2*19+2)-24]/2
= 8 units

Am I right? Thank you so much!

 

[ksmi117]

When I drew out the structure I got 38 hydrogens which means 1 unit of unsaturation (just the ring on the side chain)