Editing Morphine (section)

===Structure description===
[[File:Benzylisoquinoline structure in Morphine.svg|thumb|class=skin-invert-image|Chemical structure of morphine. The [[benzylisoquinoline]] backbone is shown in green.]]
[[File:Morphine numbered.svg|thumb|class=skin-invert-image|Morphine structure showing its standard ring lettering and carbon numbering system{{citation needed|date=February 2020}}]]
[[File:Morphine chemical structure in 3D.png|thumb|class=skin-invert-image|Same structure, but in a three-dimensional perspective]]
Morphine is a [[benzylisoquinoline]] alkaloid with two additional ring closures.<ref>{{cite book |title=Triboluminescence: Theory, Synthesis, and Application | vauthors = Olawale DO, Okoli OO, Fontenot RS, Hollerman WA |edition=illustrated |publisher=Springer |year=2016 |isbn=978-3-319-38842-7 |page=193 |url=https://books.google.com/books?id=5G6zDAAAQBAJ}} [https://books.google.com/books?id=5G6zDAAAQBAJ&pg=PA193 Extract of page 193]</ref> As Jack DeRuiter of the Department of Drug Discovery and Development (formerly, Pharmacal Sciences), Harrison School of Pharmacy, Auburn University stated in his Fall 2000 course notes for that earlier department's "Principles of Drug Action 2" course, "Examination of the morphine molecule reveals the following structural features important to its pharmacological profile...{{blockquote|
# A rigid [[pentacyclic]] structure consisting of a [[benzene]] ring (A), two partially unsaturated [[cyclohexane]] rings (B and C), a [[piperidine]] ring (D) and a [[tetrahydrofuran]] ring (E). Rings A, B, and C are the [[phenanthrene]] ring system. This ring system has little conformational flexibility...
# Two hydroxyl functional groups: a C3-[[phenol]]ic [hydroxyl group] (p''K''<sub>a</sub> 9.9) and a C6-[[allyl]]ic [hydroxyl group],
# An [[ether]] linkage between E4 and E5,
# [[Saturated and unsaturated compounds|Unsaturation]] between C7 and C8,
# A basic, [tertiary]-amine function at position 17, [and]
# [Five] centers of chirality (C5, C6, C9, C13, and C14) with morphine exhibiting a high degree of stereoselectivity of analgesic action."<ref name="urlwww.auburn.edu">{{cite web |url = http://www.auburn.edu/~deruija/opioids_morphine.pdf |title = Narcotic analgesics: morphine and "peripherally modified" morphine analogs | vauthors = DeRuiter J |date = Fall 2000 |website = Principles of Drug Action 2 |publisher = Auburn University |url-status = live |archive-url = https://web.archive.org/web/20120111171903/http://www.auburn.edu/~deruija/opioids_morphine.pdf |archive-date = 11 January 2012 }}</ref>{{better source needed|date=February 2020}}{{update after|2020|2|8}}}}<!-- THIS HANDOUT FOR A COLLEGE CLASS IS NOT AN ADEQUATE SOURCE, BUT IT SOLVES THE OPENING PLAGIARISM ISSUE. PLEASE RE-DEVELOP THIS PARAGRAPH, FROM A RELIABLE, PEER-REVIEWED SECONDARY SOURCE. -->

Morphine and most of its derivatives do not exhibit optical isomerism, although some more distant relatives like the morphinan series (levorphanol, dextrorphan, and the racemic parent chemical racemorphan) do,<ref>{{cite journal | vauthors = Way EL, Adler TK | title = The biological disposition of morphine and its surrogates | journal = Bulletin of the World Health Organization | volume = 27 | pages = 359–394 | date = 1962 | issue = 3 | pmid = 13999272 | pmc = 2555766 }}</ref> and as noted above stereoselectivity in vivo is an important issue.{{citation needed|date=February 2020}}