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From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: sci.bio
Subject: Re: Omega-3 fatty acids
Summary: YASCN (Yet Another Scheme for Chemical Nomenclature)
Keywords: unsaturated fatty acids
Message-ID: <3534@kitty.UUCP>
Date: 3 Dec 89 05:20:29 GMT
References: <859@wrgate.WR.TEK.COM> <3531@kitty.UUCP> <25773343.1707@rpi.edu>
Organization: Recognition Research Corp., Clarence, NY
Lines: 29

In article <25773343.1707@rpi.edu>, jdh@pawl.rpi.edu (Joseph Herrenkohl) writes:
> The  symbol omega refers to the position of a double bond in unsaturated
> fatty acids. Usually the numbering scheme is based on the carboxyl group
> and the position(s) of the double bond(s) are indicated by the superscript
> delta. However an alternative (archaic?) scheme numbers from the terminal
> methyl carbon - the position is then indicated by omega. For example,
> linoleic acid is (delta)9,12-octadecadienoic acid or (omega)6,9-
> octadecadienoic acid.

	Oh, great - another scheme for chemical nomenclature. :-)

	Pardon me for a moment while I air a pet gripe.  As far as I know,
fatty acids haven't changed in the past 20 years since I've been out of
college - so why should the nomenclature change?

	As I learned it, linoleic acid was alternatively referred to by the
designation 9,12-octadecadienoic acid.  Period.  No delta in front of the
9,12 and no alternative omega scheme.  As a point of comparison, linolenic
acid (three double carbon bonds) is 9,12,15-octadecatrienoic acid.  Now,
if one wanted to be a IUPAC purist, one would merely write these fatty acids
as cis,cis-9,12-octadecadienoic acid or cis,cis,cis-9,12,15-octadecatrienoic
acid.

	What could be *simpler*?

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