Rubiadin

{{Chembox | ImageFile = Rubiadin.svg | ImageSize = 200px | ImageAlt = | PIN = 1,3-Dihydroxy-2-methylanthracene-9,10-dione | OtherNames = Rubiadine; 1,3-Dihydroxy-2-methyl-9,10-anthraquinone; 1,3-Dihydroxy-2-methylanthraquinone |Section1={{Chembox Identifiers | CASNo = 117-02-2 | CASNo_Ref = {{cascite|correct|CAS}} | UNII_Ref = {{fdacite|correct|FDA}} | UNII = CY0UH3X06R | EINECS = | ChemSpiderID = 110563 | PubChem = 124062 | InChI=1S/C15H10O4/c1-7-11(16)6-10-12(13(7)17)15(19)9-5-3-2-4-8(9)14(10)18/h2-6,16-17H,1H3 | InChIKey= IRZTUXPRIUZXMP-UHFFFAOYSA-N | SMILES = CC1=C(C=C2C(=C1O)C(=O)C3=CC=CC=C3C2=O)O }} |Section2={{Chembox Properties | C=15 | H=10 | O=4 | Appearance = | Density = | MeltingPt = | BoilingPt = | Solubility =}} |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt =}} }}

'''Rubiadin''' is a bioactive anthraquinone dye that occurs naturally in several plant species, including ''Morinda citrifolia''.<ref>{{cite journal|pmid=24062780|year=2013|last1=Bussmann|first1=RW|last2=Hennig|first2=L|last3=Giannis|first3=A|last4=Ortwein|first4=J|last5=Kutchan|first5=TM|last6=Feng|first6=X|title=Anthraquinone Content in Noni (Morinda citrifolia L.)|volume=2013|article-number=208378|doi=10.1155/2013/208378|pmc=3770026|journal=Evidence-Based Complementary and Alternative Medicine|doi-access=free}}</ref>

== History == Although rubiadin was first isolated in 1853 by Edward Schunck from the Rubia tinctorum, it was not until 1893 that Schunck and Leon Marchlewski succeeded in isolating rubiadin glucoside from Dutch madder root. The first synthesis of the compound was achieved in 1927.<ref>{{citation|author=Elfed Thomas Jones, Alexander Robertson |date=1930 |doi=10.1039/JR9300001699 |pages=1699–1709 |periodical=Journal of the Chemical Society (Resumed) |title=CCXXIII.—Syntheses of glucosides. Part V. Two new syntheses of rubiadin and syntheses of 1-O-methylrubiadin and of rubiadin glucoside}}</ref>

== Occurrence == Rubiadin occurs in plants of the genus ''Rubia'' and others.<ref name="caymanchem.com">Cayman Chemical: [https://www.caymanchem.com/product/11753/rubiadin Rubiadin (C.I. 75350, CAS Number: 117-02-2) | Cayman Chemical], retrieved 21 November 2025.</ref><ref name="Herbert Baxter, J.B. Harborne, Gerald P. Moss">{{citation|author=Herbert Baxter, J.B. Harborne, Gerald P. Moss |date=1998 |isbn=978-0-203-48375-6 |pages=557 |publisher=CRC Press |title=Phytochemical Dictionary A Handbook of Bioactive Compounds from Plants, Second Edition |url={{Google books|oT9ZDwAAQBAJ||page=557}}}}</ref><ref>{{citation|author=Rainer W. Bussmann, Lothar Hennig, Athanassios Giannis, Jutta Ortwein, Toni M. Kutchan, Xi Feng |date=2013 |doi=10.1155/2013/208378 |issue=1 |pages=208378 |periodical=Evidence-Based Complementary and Alternative Medicine |pmid=24062780 |title=Anthraquinone Content in Noni (Morinda citrifolia L.) |volume=2013 |pmc=3770026 |doi-access=free}}</ref> It is one of the pigments of dyer's madders, where it is present as a glucoside. Its monomethyl ether has been isolated from Morinda longiflora and Morinda citrifolia.<ref>{{citation|author=Florence D. Stouder, Roger Adams |date=1927 |doi=10.1021/ja01407a030 |issue=8 |pages=2043–2045 |periodical=Journal of the American Chemical Society |title=Polyhydroxy-methylanthraquinones. ix. Contribution to the Structure of Rubiadin |volume=49 |bibcode=1927JAChS..49.2043S}}</ref>

== Extraction and presentation == Several methods for synthesizing rubiadin have been described. One approach is the synthesis of rubiadin from phthalic anhydride and 2,6-dihydroxytoluene in two reaction steps. However, the yields of both steps were low (33% and 54%, respectively), and the reproducibility of this method was very poor. Another synthesis route proceeds via 2-methylpurpurin (1,3,4-trihydroxy-2-methylanthraquinone), but this method requires five steps and each reaction step affords a low yield. A further described synthesis of rubiadin derivatives involves Diels-Alder reactions with halogenated naphthoquinones and dienes. In addition, rubiadin can be obtained by the condensation of 3-bromo-2,6-dimethoxytoluene with a phthalide.<ref>{{citation|author=Toshiyuki Takano, Tomomi Kondo, Fumiaki Nakatsubo |date=2006 |doi=10.1007/s10086-005-0727-6 |issue=1 |pages=90–92 |periodical=Journal of Wood Science |title=Facile synthesis of rubiadin by microwave heating |volume=52 |bibcode=2006JWSci..52...90T}}</ref><ref>{{citation|author=Mohd Nasarudin Watroly, Mahendran Sekar, Shivkanya Fuloria, Siew Hua Gan, Srikanth Jeyabalan, Yuan Seng Wu, Vetriselvan Subramaniyan, Kathiresan V. Sathasivam, Subban Ravi, Nur Najihah Izzati Mat Rani, Pei Teng Lum, Jaishree Vaijanathappa, Dhanalekshmi Unnikrishnan Meenakshi, Shankar Mani, Neeraj Kumar Fuloria |date=2021 |doi=10.2147/DDDT.S338548 |pages=4527–4549 |periodical=Drug Design, Development and Therapy |title=Chemistry, Biosynthesis, Physicochemical and Biological Properties of Rubiadin: A Promising Natural Anthraquinone for New Drug Discovery and Development |volume=15 |doi-access=free |pmc=8576757}}</ref>

== Properties == Rubiadin is a yellow to orange solid,<ref name="Sigma">{{Sigma-Aldrich|Supelco|74553|Name=Rubiadin, analytical standard|Abruf=2025-11-21}}</ref><ref name="W. Karrer">{{citation|author=W. Karrer |date=2013 |isbn=978-3-0348-5142-8 |pages=502 |publisher=Springer-Verlag |title=Konstitution und Vorkommen der organischen Pflanzenstoffe (exclusive Alkaloide) |url={{Google books|yQycBgAAQBAJ||page=502}}}}</ref> and is soluble in organic solvents.<ref name="caymanchem.com" />

== Use == Rubiadin is a constituent of natural colorants.<ref name="K. Lacasse, Werner Baumann">{{citation|author=K. Lacasse, Werner Baumann |date=2012 |isbn=978-3-642-18898-5 |pages=940 |publisher=Springer Science & Business Media |title=Textile Chemicals Environmental Data and Facts |url={{Google books|7RH2CAAAQBAJ||page=940}}}}</ref>

==References== {{reflist}}

Category:Dihydroxyanthraquinones Category:Resorcinols

Rubiadin

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