Comments on: Pyranoses and Furanoses: Ring-Chain Tautomerism In Sugars https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/ Fri, 17 Feb 2023 16:05:23 +0000 hourly 1 https://wordpress.org/?v=6.6.2 By: James Ashenhurst https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/#comment-645955 Wed, 11 Jan 2023 18:41:50 +0000 https://www.masterorganicchemistry.com/?p=10855#comment-645955 In reply to Angel.

Good point. I should show it!

It would look a lot like how it’s drawn in this post on proton transfer – see Proton Transfer

]]> By: Angel https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/#comment-637102 Sun, 04 Sep 2022 09:09:11 +0000 https://www.masterorganicchemistry.com/?p=10855#comment-637102 Hello
for reaction between aldehyde and alcohol , proton gets transferred to the carbonyl group right, and we considered that the alcohol is in excess
how does proton transfer occur in case of ring-chain tautomerism …i couldnt get that part since you havent shown it there !

]]> By: James Ashenhurst https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/#comment-634560 Wed, 03 Aug 2022 20:24:47 +0000 https://www.masterorganicchemistry.com/?p=10855#comment-634560 In reply to Alexa.

Can you snap a photo of the text in the book and send it to me at james@masterorganicchemistry.com ? I would prefer to read what the book says and start from there. Just want to double check that we’re all using the same terms.

]]> By: Alexa https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/#comment-634549 Wed, 03 Aug 2022 16:38:40 +0000 https://www.masterorganicchemistry.com/?p=10855#comment-634549 Hey James, great post! I’m reading some conflicting information in a textbook (essentials of glycobiology) which states that in the alpha anomer of D-glucose, C-1 and C-5 have the same configuration and are on the same plane, while the beta anomer has different conformations.

]]> By: Carbohydrates Questions & Answers 2020 - Pick Subject https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/#comment-631939 Mon, 04 Jul 2022 03:38:26 +0000 https://www.masterorganicchemistry.com/?p=10855#comment-631939 […] form accounts for the powerful sweetness of honey. Explain the enzymatic conversion of precursors to b-d-pyranose, using diagrams to illustrate your […]

]]> By: Ifeanyi paul https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/#comment-597490 Tue, 02 Feb 2021 22:53:20 +0000 https://www.masterorganicchemistry.com/?p=10855#comment-597490 A quick one James.

Show the different step in the mechanism of reaction whereby D glucose gives rise to pyranose and furanose forms.

]]> By: Noble JOY https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/#comment-597487 Tue, 02 Feb 2021 22:40:46 +0000 https://www.masterorganicchemistry.com/?p=10855#comment-597487 Hi James,
I’m taking a course in Biochemistry and I just dropped by for an assignment.
super grateful I came here.
Thanks for the somewhat simplified and informative posts you share.

]]> By: Sarah Roman https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/#comment-581548 Thu, 25 Jun 2020 07:15:06 +0000 https://www.masterorganicchemistry.com/?p=10855#comment-581548 Amazing topic about sugar chemistry. I am a chemistry student and i read your blog with lot of interest and joy. Thank you for sharing informative blog.

]]> By: James Ashenhurst https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/#comment-563234 Thu, 05 Sep 2019 17:32:39 +0000 https://www.masterorganicchemistry.com/?p=10855#comment-563234 In reply to Farhan Shabir.

Great question! The answer is not obvious! The hydroxyl groups of carbohydrates can hydrogen-bond both with each other and with the solvent. Each isomer (alpha+ beta furanose, alpha + beta pyranose) has a unique three-dimensional structure and the most favored structure will be that which maximizes the strength of the inter- and intramolecular hydrogen bonds. To make it even more complicated, there are solvent effects too. In water, fructose is 42% furanose and even higher (75% in DMSO See: https://doi.org/10.1002/mrc.1260280402). However in the gas phase, fructose favors a pyranose form (dx.doi.org/10.1021/ja312393m | J. Am. Chem. Soc. 2013, 135, 2845−2852).
Sorry I can’t give you an easier answer!

]]> By: Farhan Shabir https://www.masterorganicchemistry.com/2017/07/13/pyranoses-and-furanoses-ring-chain-tautomerism-in-sugars/#comment-558669 Tue, 23 Jul 2019 13:26:50 +0000 https://www.masterorganicchemistry.com/?p=10855#comment-558669 Hey James, a quick question.
Why is the furanose form of fructose(~29%) more dominant than that of glucose (<1%)?

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