[mobfesk2]

Hi Chem Forumers,

Just a quick question for those sugar/organic chemists. Have I drawn the structure of Benzyl Lactose (Lac-OBn) correctly? See attached pic

Thank you !! 

[jpg28]

Hello mobfesk2!

I don't really know the compound by heart, but I think there are some things missing in the structure you provided. First of all, I'm pretty sure that what you provided was only a phenyl group. Look up the structure, for example, of benzyl chloride. You will notice something missing with what you drew.

Second, about the structure of lactose. It's made up of galactose and glucose connected via a beta(1,4)-O-glycosidic bond; however, the sugar moiety on the right side of your structure (for Glucose) seems to lack an -OH group. Check your structure once more. I'm positive that you'll be able to find out what's missing.

[AWK]

Moreover, there are two isomers of Lac-OBn - alpha and beta

[mobfesk2]

Hi there,

Yes I totally forgot to add the OH group on position 3 of glucose. Thanks! And I think this would be the correct structure of LacOBn. I would say it's in the beta configuration. Please could you check this for me?

Thanks a lot guys!!!

Much appreciated!

[AWK]

OK
http://www.elmhurst.edu/~chm/vchembook/546lactose.html