please explain carbon chain naming

[elv09]

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hey guys, im having a problem with sugars
i was told that sugars have a chain form, and a ring form, which both exist in equilibrium (alongside alpha-beta isomerism)

the trouble im having, is naming the carbons of sugars in ring form. how do i tell which one is C1, C2, etc?

thanks guys

[brenton1987]

Originally Posted by elv09

the trouble im having, is naming the carbons of sugars in ring form. how do i tell which one is C1, C2, etc?

Looking at the ring there will be a number of carbon atoms and a single oxygen atom. The carbon atoms attached to the oxygen atom are the ones of interest.

One of the carbon atoms will not have any other oxygen atoms bonded to it. The other carbon atom will have a hydroxyl group bonded it. The carbon with the hydroxyl is carbon 1. Continue numbering around the ring and along the tail.

[elv09]

so, the rule is - the anomeric carbon is always C1?

[brenton1987]

Originally Posted by elv09

so, the rule is - the anomeric carbon is always C1?

Yes

[marcquelle]

Originally Posted by elv09

so, the rule is - the anomeric carbon is always C1?

????????