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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: madscientist on June 18, 2007, 12:26:46 AM

Title: functional groups
Post by: madscientist on June 18, 2007, 12:26:46 AM
Does anyone know if and why glusose 6-phosphate would be considered an ester?

                                                                        O
                                                                       ||
As far as i can  tell it does not have an ester group -C-O-

                                                              O
                                                             ||
It does have an aldehyde functional group    -C-H   so I thought it would be considered an aldehyde....

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fwww.biocrawler.com%2FPictures%2FChemical_Structures%2Fthumb_Glucose-6-phosphate.png&hash=f2d35adaabac77c3c3ff2b33f26a910a7c2fe136)
Any ideas?

Cheers,

M
Title: Re: functional groups
Post by: Yggdrasil on June 18, 2007, 02:59:30 AM
It is a phosphoester.  Recall that esters can be thought of as a combination of an alcohol and an acid.   In this case, the OH of the glucose acts as the alcohol and phosphoric acid acts like the acid.  In this case the ester looks like:
    O
    ||
-O-P-

Another common type of ester in biology is a thioester:

    O
    ||
-S-C-

[Edit: thanks Kremar]
Title: Re: functional groups
Post by: kremar on June 18, 2007, 11:01:18 AM
I've always heard of compounds like
    O
    ||
-S-C-

being refered to as thioesters. This compounds are quite common on biochemistry, like condensations of acids with Coenzime A.
Title: Re: functional groups
Post by: english on June 18, 2007, 01:25:51 PM
Quote from: Yggdrasil on June 18, 2007, 02:59:30 AM
It is a phosphoester.
Title: Re: functional groups
Post by: Doc_1998 on June 18, 2007, 11:46:10 PM
to add to the list Picric acid does not have carboxylic acid group. Because of the presence of three phenolic OH its acidity is as high as acid and hence it is called as acid.
Title: Re: functional groups
Post by: kiwi on June 19, 2007, 04:21:02 AM
Quote from: Doc_1998 on June 18, 2007, 11:46:10 PM
to add to the list Picric acid does not have carboxylic acid group. Because of the presence of three phenolic OH its acidity is as high as acid and hence it is called as acid.

I'm not sure what you think picric acid is, but it's 2,4,6 trinitrophenol. It has one phenol group - the electron withdrawing properties of the nitro groups cause the phenol to extra acidic.