Oxazines
{{Short description|E heterocyclic organic compounds containing one oxygen and one nitrogen atom}}
Oxazines are heterocyclic organic compounds containing one oxygen and one nitrogen atom in a cyclohexa-1,4-diene ring (a doubly unsaturated six-membered ring). Isomers exist depending on the relative position of the heteroatoms and relative position of the double bonds.
By extension, the derivatives are also referred to as oxazines; examples include ifosfamide and morpholine (tetrahydro-1,4-oxazine). A commercially available dihydro-1,3-oxazine is a reagent in the Meyers synthesis of aldehydes. Fluorescent dyes such as Nile red and Nile blue are based on the aromatic compound benzophenoxazine. Cinnabarine and cinnabaric acid are two naturally occurring dioxazines, being derived from biodegradation of tryptophan.{{cite journal | vauthors = Stone TW, Stoy N, Darlington LG | title = An expanding range of targets for kynurenine metabolites of tryptophan | journal = Trends in Pharmacological Sciences | volume = 34 | issue = 2 | pages = 136–43 | date = February 2013 | pmid = 23123095 | doi = 10.1016/j.tips.2012.09.006 | url = http://eprints.gla.ac.uk/77300/1/77300.pdf }}
Dioxazines
Dioxazines are pentacyclic compounds consisting of two oxazine subunits. A commercially important example is the pigment pigment violet 23.{{cite book | vauthors = Chamberlain T | chapter = Dioxazine violet pigments | title = High Performance Pigments | veditors = Smith HM | publisher = John Wiley & Sons | date = 2002 | pages = 185–194 | doi = 10.1002/3527600493.ch12 | isbn = 978-3-527-30204-8 }}
Benzoxazines
Benzoxazines are bicyclic compounds formed by the ring fusion of a benzene ring with an oxazine. Polybenzoxazines are a class of polymers formed by the reaction of phenols, formaldehyde, and primary amines which on heating to ~200 °C (~400 °F) polymerise to produce polybenzoxazine networks.{{Cite journal | vauthors = Tsotra P, Setiabudi F, Weidmann U | title = Benzoxazine chemistry: a new material to meet fire retardant challenges of aerospace interiors applications. | journal = Engineering | date = 2008 | s2cid = 18422389 | url = http://www.escm.eu.org/docs/eccm13/0721.pdf }} The resulting high molecular weight thermoset polymer matrix composites are used where enhanced mechanical performance, flame and fire resistance compared to epoxy and phenolic resins is required.{{cite book | vauthors = Tietze R, Chaudhari M | chapter = Advanced benzoxazine chemistries provide improved performance in a broad range of applications | veditors = Ishida H, Agag T | title = Handbook of Benzoxazine Resins | publisher = Elsevier B.V. | date = 2011 | pages = 595–604 | doi = 10.1016/B978-0-444-53790-4.00079-5 | isbn = 978-0-444-53790-4}}
Physical properties
Oxazine dyes exhibit solvatochromism.{{cite journal | vauthors = Fleming S, Mills A, Tuttle T | title = Predicting the UV-vis spectra of oxazine dyes | journal = Beilstein Journal of Organic Chemistry | volume = 7 | pages = 432–441 | date = 2011-04-15 | pmid = 21647257 | pmc = 3107493 | doi = 10.3762/bjoc.7.56 }}
Images
File:Morpholine-flat-2D-skeletal.png|Morpholine
File:10H-phenoxazine 200.svg|Phenoxazine
File:C.I. Pigment Violet 23.svg|Pigment violet 23 is a commercially useful pigment.
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References
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