The Vespiary

The Hive => Chemistry Discourse => Topic started by: masterofpuppets on February 27, 2002, 12:34:00 AM

Title: Which isomer??
Post by: masterofpuppets on February 27, 2002, 12:34:00 AM

How does one work out what isomer will be form (d or l or both) from a given reaction??  MOP knows that l-pseudo goes to d-meth via the RPIE reaction - is the naming of the l and d arbitary or do things change around during the reaction?

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I wouldn't do that if I were you.....

Title: Re: Which isomer??
Post by: foxy2 on February 27, 2002, 01:06:00 AM

MOP knows that l-pseudo goes to d-meth via the RPIE reaction - is the naming of the l and d arbitary or do things change around during the reaction?

Its not arbitrary, the chrial carbon which the "l-" in l-pseudo refers to is the one that has the -OH group, remove the -OH group and this carbon is no longer chrial. The "d-" in d-meth refers to the carbon that has the nitrogen attached, this carbon is unaffected in the reaction and its orientation is "d-" in pseudoephedrine, ephedrine and d-methamphetamine. 

I am unsure if my nomenclature is correct but thats why

Learn more at these sites

http://ep.llnl.gov/msds/orgchem/stereochem.html (http://ep.llnl.gov/msds/orgchem/stereochem.html)

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Title: Re: Which isomer??
Post by: Vlad on February 27, 2002, 04:19:00 AM

To put it simply:

For whatever reason, pseudo doesn't switch. d-pseudo produces d-meth. l-pseudo is very uncommon. Also, it is more expenisive than d-pseudo. Ephedrine switches though; l-eph makes d-meth and d-eph makes l-meth.