Talk:Diastereomer

message: The following explanation given in the article is wrong: "In simple terms two stereoisomers are said to be diastereoisomers of each other if only one stereogenic centre differs between the two stereoisomers. It's a definition of an epimer. 
References: 
- Garrett, Grisham "Biochemistry" ("Pairs of isomers that have opposite configurations at one or more of the chiral centers but are not mirror images of each other are called diastereoisomers", 2nd ed., 1999, p. 213)
- McMurray "Organic Chemistry"
* The distinction is exactly one for an epimer and one or more stereocenters for the Diastereomer, I have added your reference and definition V8rik 20:28, 28 November 2006 (UTC)

message: --212.49.92.124 08:59, 19 July 2007 (UTC)
thread_title:  congrads 

message: Either the Fisher Projections are not following convention (vertical, into page; horizontal, out of page), is plain wrong, or conflicts with the article on Fisher Projections. Can someone fix the pictures.
* I am unable to see anything wrong with the image, convert the first row Fisher images by a 90 degrees rotation around the carbon chain axis and you will see they are identical with the second row depictions. Lets have discussion first V8rik (talk) 17:26, 12 December 2007 (UTC)
thread_title:  Problem with Fischer Projections 

message: May I suggest a slight re-wording of the following sentence:  "the number of configurational isomers of a molecule can be determined by calculating 2n, where n=the number of chiral centers in the molecule. This holds true except in cases where the molecule has meso forms." to "the number of configurational isomers of a molecule can not be more than 2^n, where n equals the number of chiral centers in the molecule. The number of stereoisomers realized is less than 2^n by the number of meso forms." Gaedheal (talk) 16:21, 5 November 2009 (UTC)
thread_title:  reword 

message: ::Diastereomerism occurs when two or more stereoisomers of a compound have different configurations at one or more (but not all) of the equivalent (related) stereocenters and are not mirror images of each other.
The above quote from the first paragraph is stating the same point in two different ways: when al chiral centers have the opposite configuration, the molecule will be transformed in its mirror image, as far as I know, so the last part of it not needed to make the point. On th eother hand, indicating its truth would not harm, when related to the twisting of the conformations.T.vanschaik (talk) 10:56, 9 February 2012 (UTC)
thread_title:  Confihuration and mirror images 

message: "Diastereomers have different physical properties and different reactivity, unlike enantiomers."
enantiomers show different reactivity when space comes into account (biological, catalysis, etc), you can see this in the enantiomers page... i'm rephrasing this  — Preceding unsigned comment added by 168.96.204.43 (talk) 19:41, 19 March 2012 (UTC)
thread_title:  Comparation w/ enantiomers 

message: These are NOT the IUPAC descriptors for relative stereochemistry. There are multiple reasons: There are multiple requirements for erythro and threo to be valid:	1. The principal carbon chain cannot be assigned an erythro/threo descriptor. 2. Only substituents of the highest priorities can be compared. 3. Substituents must be adjacent. Therefore we now use syn and anti. SEE http://goldbook.iupac.org/E02212.html "Descriptors of the diastereoisomers of an acyclic structure or partial structure having two stereogenic centres. This notation is derived from carbohydrate nomenclature. The extension of this system has given rise to conflicting interpretations of these prefixes. It is recommended that for such cases the l, u or  R*, S* system should be used." ★Ffgamera★ - My page! · Talk to me!· Contribs 13:46, 4 July 2013 (UTC)
replies: text: I updated the article to say exactly what that authoritative ref says regarding when (not to) use it. DMacks (talk) 09:47, 13 July 2013 (UTC)
thread_title:  Erythro and threo 

message: Erythro seems almost certain to be derived from Greek eruthro- meaning "red" which turns up in various scientific terms, but even assuming this to be the case, finding a confirming (or denying) source has proven difficult.
Threo is even more difficult as it doesn't seem to be well-attested anywhere. It looks as though it might also be Greek, but if it is, there's slim to no usage of the prefix in literature. Furthermore, the apparent conjugations of what there is do not seem to match those of erythro. Sister site Wiktionary has an entry for the term, but is also lacking / requesting an etymology.
If not Greek, one possibility is that it's derived from an anagram of erythro; there is at least one other example of new scientific terms being created through anagrams of others. (Specifically, I'm thinking of the spider genera Tegenaria and Eratigena for which the latter is a deliberate anagram of the former).
While it's not strictly necessary to have the etymology of scientific terms, I believe it could be a worthwhile addition if only a source could be found. Cyrek (talk) 21:29, 13 November 2018 (UTC)
thread_title:  Etymology of Erythro and Threo? 

message: — Assignment last updated by 123pickles456 (talk) 01:08, 10 October 2022 (UTC)
thread_title: Wiki Education assignment: Honors Organic Chemistry I