The structure of (+)-catechin differs from (-)-epicatechin only in their spatial arrangement of the atoms around the 2nd and 3rd carbon atoms in the pyran ring. I hope to illustrate that point with the following structural depictions.
The structures of (+)-catechin, (-)-epicatechin, and (-)-epigallocatechin shown below will consist of the following:
- first as a bond-line structural representation
- second as a 3D representation showing the relationship between the substituents on the second and third carbons
- lastly as a space filling model
As mentioned above, catechins are important because they are contained in the seeds of the grape and decline after veraison. If bitter characters are detected in a wine, they may have come from these catechins. In addition, catechins are the monomeric units that can polymerize and lead to tannin formation, the subject of a future blog. Stay tuned!
References:
1. Douglas Adams, VI257, Lesson 8, pg. 50.
2. Jackson, Ronald S., Wine Science: Principles and Applications, Third Edition, Elsevier, Academic Press, 2008, pg. 283.
All structures were drawn by the freely available drawing program from ACD Labs called ACD/ChemSketch Freeware.
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