pyran


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py·ran

 (pī′răn′)
n.
Either of two isomeric unsaturated compounds with the formula C5H6O, having a ring of five carbon atoms and one oxygen atom.

[pyrone, heterocyclic compound (pyr(o)- + -one) + -an.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

pyran

(ˈpaɪræn; paɪˈræn)
n
(Elements & Compounds) an unsaturated heterocyclic compound having a ring containing five carbon atoms and one oxygen atom and two double bonds. It has two isomers depending on the position of the saturated carbon atom relative to the oxygen
[C20: from pyro- + -an]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

py•ran

(ˈpaɪ ræn, paɪˈræn)

n.
either of two compounds having the formula C5H6O, containing one oxygen and five carbon atoms arranged in a six-membered ring.
[1900–05; pyr(one) a heterocyclic ketone (< Greek pŷr fire + -one) + -an2]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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References in periodicals archive ?
Flavonoids are phenolic compounds that differ in their chemical structure, have 15 carbon atoms in the C6-C3-C6 form, based on the nucleus of two benzene rings, A and B, attached to a pyran ring, C (Figure 1).
Among "pyran series," compound 36 demonstrated the most interesting inhibitory effect showing 15 [micro]M MIC value; derivative 35 was able to interfere with the NF-[kappa]B/DNA interaction at 35 [micro]M MIC.
Based on the saturation level and opening of the central pyran ring, flavonoids can be classified into distinct subclasses including flavanols, flavanones, flavanonols, flavonols, anthocyanidins, isoflavones, and flavones [14-16].
To facilitate this [pi]-[pi] stacking interaction, compound 6 in MAO-B stays farther away from FAD than that in MAO-A (Figures 7(e) and 7(f)).The sulfhydryl hydrogen of residue C172 in MAO-B complex also interacts with pyran and ketone oxygens of 6, which was correspondingly replaced by residue N181 in complex MAO-A (white-circled in Figures 7(c) and 7(d), resp.).
In addition to lapachol (2, Figure 1), different structural types of naphthoquinones, such as pyran and furanonaphthoquinones, are found in Bignoniaceae [18, 19] and disclose abroad spectrum of biological activities, including antitumor [20-23], trypanocidal [24], anti-inflammatory [7], antifungal [25], and antiparasitic activities [26-33].
A total of 16 volatile compounds with known antimicrobial and antioxidant properties, such as alcohol, ketone, aliphatic acid, benzene compound, hydrocarbon, furan, and pyran derivatives, have been identified, and the best antibacterial activity has been demonstrated by the fraction GCF3 (5 mg/ml) [11].
Carbonara et al., "Novel pyran based dyes for application in dye sensitized solar cells," Dyes and Pigments, vol.
One is the ring-opening reaction of the depolymerized xylan unit through the cleavage of the hemiacetal bond (between oxygen and C-1 on the pyran ring), followed by dehydration between the hydroxyl groups on the C2 and C5 positions.
The reaction mixture was subjected to the reaction with [BF.sub.3] in C[H.sub.2][Cl.sub.2] for intramolecular closure of the pyran ring.
In addition, chromone (a derivative of benzopyran with a substituted keto group on the pyran ring), dinorxanthane sesquiterpene, and other substances isolated from T.