[lespaul]

Hi All,

Im a biologist and have a quick question:

Whats the difference between a carbonyl (C=O) and a alpa-carbonyl?

I assume it has something to do with position, but not sure. If anyone have a pictures thay can send me, it would be best. Thanks

Jim

[Yggdrasil]

Do you mean carbonyl and alpha carbon?  The alpha carbon is just a carbon atom that is directly adjacent to a carbonyl carbon (see picture). Similarly, an beta carbon is one carbon away from a carbonyl carbon, a gamma carbon is two carbons away from a carbonyl carbon, etc.  Also useful to know is that an alpha amino group is directly attached to an alpha carbon, a beta amino group is directly attached to a beta carbon, etc.

[Nick.Sparrow]

I think you are missunderstanding a simple thing. Alpha-carbonyl is a carbonyl group in alpha-position to something..., e.g. carboxilic group (see the post from Yggdrasil)

Example

butyric acid                                  CH3CH2CH2COOH
alpha-carbonyl butyric acid             CH3CH2COCOOH
betta-carbonyl butyric acid             CH3COCH2COOH