Hydroxynaphthoquinone

A '''hydroxynaphthoquinone''' (formula: {{chem|C|10|H|6|O|3}}) is any of several organic compounds that can be viewed as derivatives of a naphthoquinone through replacement of one hydrogen atom (H) by a hydroxyl group (-OH).

In general, the term may mean any naphthoquinone derivative where any number ''n'' of hydrogens have been replaced by ''n'' hydroxyls, so that the formula is {{chem|C|10|H|6|O|2+''n''}}. In this case the number ''n'' (which is between 1 and 6) is indicated by a multiplier prefix ('''mono'''-, '''di'''-, '''tri'''-, '''tetra'''-, '''penta'''-, or '''hexa'''-).

The unqualified term "hydroxynaphthoquinone" usually means a derivative of 1,4-naphthoquinone. Other hydroxy- compounds can be derived from other isomers of the latter, such as 1,2-naphthoquinone and 2,6-naphthoquinone. The IUPAC nomenclature uses '''dihydronaphthalenedione''' instead of "naphthoquinone", with the necessary prefixes to indicate the positions of the carbonyl oxygens (=O) — as in 5,8-dihydroxy-1a,8a-dihydronaphthalene-1,4-dione (= 5,8-dihydroxy-1,4-naphthoquinone).

The hydroxynaphtoquinones (in the particular or the general sense) include many biologically and industrially important compounds, and are a building-block of many medicinal drugs.<ref name=khalafy>{{ cite journal |author1=Khalafy, J. |author2=Bruce, J. M. | year = 2002 | title = Oxidative Dehydrogenation of 1-Tetralones: Synthesis of Juglone, Naphthazarin, and α-Hydroxyanthraquinones | journal = Journal of Sciences, Islamic Republic of Iran | volume = 13 | issue = 2 | pages = 131–139 | url = http://www.sid.ir/en/VEWSSID/J_pdf/97320020202.pdf | format = pdf }}</ref><ref name=thomson71>{{ cite book | author = Thomson, R. H. | title = Naturally Occurring Quinones | url = https://archive.org/details/naturallyoccurri0000thom | url-access = registration | publisher = Academic Press | location = London | year = 1971 }} Quoted by Khalafy and Bruce.</ref><ref name=thomson87>{{ cite book | author = Thomson, R. H. | title = Naturally Occurring Quinones III | publisher = Chapman and Hall | location = London | year = 1987 }} Quoted by Khalafy and Bruce.</ref>

== (Mono)hydroxynaphtoquinones ==

===From 1,4-naphthoquinone=== Due to its symmetry there are only three isomers:

*2-Hydroxy-1,4-naphthoquinone (lawsone), coloring principle of henna. *5-Hydroxy-1,4-naphthoquinone (juglone), coloring principle of black walnut.<ref>{{ cite journal |author1=Taylor, R. T. |author2=Flood, L. A. | title = Polystyrene-Bound Phenylseleninic Acid: Catalytic Oxidations of Olefins, Ketones, and Aromatic Systems | journal = The Journal of Organic Chemistry | year = 1983 | volume = 48 | issue = 26 | pages = 5160–5164 | doi = 10.1021/jo00174a003 }}</ref> Also active antimicrobial principle in ''Caesalpinia sappan'' heartwood.<ref name=lim>{{ cite journal |author1=Lim, M.-Y. |author2=Jeon, J.-H. |author3=Jeong, E. Y. |author4=Lee, C. H. |author5=Lee, H.-S. | title = Antimicrobial Activity of 5-Hydroxy-1,4-Naphthoquinone Isolated from ''Caesalpinia sappan'' toward Intestinal Bacteria | journal = Food Chemistry | year = 2007 | volume = 100 | issue = 3 | pages = 1254–1258 | doi = 10.1016/j.foodchem.2005.12.009 }}</ref> *6-Hydroxy-1,4-naphthoquinone, can be prepared from 1,7-dihydroxynaphthalene.<ref name=gotz>{{ cite journal |author1=Teuber, H.-J. |author2=Götz, N. | title = Reaktionen mit Nitrosodisulfonat, V. Mitteilung: Über die Bildung von Naphtochinonen | journal = Chemische Berichte | year = 1954 | volume = 87 | issue = 9 | pages = 1236–1251 | doi = 10.1002/cber.19540870908 }} </ref> One of the main products of photochemical oxidation of 1-naphthol.<ref name=foo>{{ cite journal |author1=Brahmia, O. |author2=Richard, C. | title = Photochemical Transformation of 1-Naphthol in Aerated Aqueous Solution | journal = Photochemical & Photobiological Sciences | year = 2005 | volume = 4 | issue = 6 | pages = 454–458 | doi = 10.1039/B504309C | pmid = 15920628 | doi-access = free }}</ref>

===From 1,2-naphthoquinone=== From 1,2-naphthoquinone (''ortho''-naphthoquinone) there are 6 possible isomers: *3-Hydroxy-1,2-naphthoquinone *4-Hydroxy-1,2-naphthoquinone<ref name=garge>{{ cite journal |author1=Garge, P. |author2=Padhye, S. |author3=Tuchagues, J.-P. | title = Iron(II) Complexes of ''ortho''-Functionalized ''para''-Naphthoquinones 1. Synthesis, Characterization, Electronic Structure and Magnetic Properties | journal = Inorganica Chimica Acta | year = 1989 | volume = 157 | issue = 2 | pages = 239–249 | doi = 10.1016/S0020-1693(00)80548-4 }} </ref><ref name=rane>{{ cite journal |author1=Rane, S. Y. |author2=Ahmed, K. |author3=Salunke-Gawali, S. | title = Temperature Effect on Ancillary μ-Carbonato Ligand Modes in Hydroxy Naphthoquinonato Copper(II) Complex: An EPR Spectroscopic and Magnetic Coupling Evidences | journal = Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry | year = 2006 | volume = 36 | issue = 5 | pages = 391–398 | doi = 10.1080/15533170600729037 }}</ref> *5-Hydroxy-1,2-naphthoquinone *6-Hydroxy-1,2-naphthoquinone *7-Hydroxy-1,2-naphthoquinone *8-Hydroxy-1,2-naphthoquinone

===From 2,3-naphthoquinone=== From 2,3-naphthoquinone, also a symmetric molecule there are only three isomers: *1-Hydroxy-2,3-naphthoquinone *5-Hydroxy-1,2-naphthoquinone *6-Hydroxy-1,2-naphthoquinone

===From 2,6-naphthoquinone=== From the symmetrical 2,6-naphthoquinone (''amphi''-naphthoquinone) there are only three:

*1-Hydroxy-2,6-naphthoquinone *3-Hydroxy-2,6-naphthoquinone *4-Hydroxy-2,6-naphthoquinone

==(Poly)hydroxynaphthoquinones== *Dihydroxynaphthoquinone *Trihydroxynaphthoquinone *Tetrahydroxynaphthoquinone *Pentahydroxynaphthoquinone *Hexahydroxynaphthoquinone

==References== {{reflist}}

Category:Hydroxynaphthoquinones