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Synthesis

The complex is generally prepared from vanadium(IV), e.g. vanadyl sulfate:¹

It can also be prepared by a redox reaction starting with vanadium pentoxide. In this reaction, some acetylacetone is oxidized to 2,3,4-Pentanetrione.²

Structure and properties

The complex has a square pyramidal structure with a short V=O bond. This d1 compound is paramagnetic. Its optical spectrum exhibits two transitions. It is a weak Lewis acid, forming adducts with pyridine and methylamine.³

Applications

It is used in organic chemistry as a catalyst for the epoxidation of allylic alcohols by tert-butyl hydroperoxide (TBHP). The VO(acac)2–TBHP system exclusively epoxidizes geraniol at the allylic alcohol position, leaving the other alkene of geraniol untouched. By comparison, m-CPBA, another epoxidizing agent, reacts with both alkenes, creating the products in a two to one ratio favoring reaction at the alkene away from the hydroxyl group. TBHP oxidizes VO(acac)2 to a vanadium(V) species which coordinates the alcohol of the substrate and the hydroperoxide, directing the epoxidation to occur at the alkene close to this coordination site.⁴⁵

Biomedical aspects

Vanadyl acetylacetonate exhibits insulin mimetic properties, in that it can stimulate the phosphorylation of protein kinase B (PKB/Akt) and glycogen synthase kinase 3 (GSK-3).⁶ It has also been shown inhibit tyrosine phosphatase (PTPase), PTPases such as PTP1B, which dephosphorylates insulin receptor beta subunit, thus increasing its phosphorylation, allowing for a prolonged activation of IRS-1, PKB, and GSK-3, allowing them to exert their anti-diabetic properties.⁷

External links

• Oxidations tutorial

References

1. Rowe, Richard A.; Jones, Mark M. (1957). "Vanadium(IV) Oxy(acetylacetonate)". Inorganic Syntheses. Inorganic Syntheses. Vol. 5. pp. 113–116. doi:10.1002/9780470132364.ch30. ISBN 978-0-470-13236-4. {{cite book}}: ISBN / Date incompatibility (help) 978-0-470-13236-4 ↩

2. Rowe, Richard A.; Jones, Mark M. (1957). "Vanadium(IV) Oxy(acetylacetonate)". Inorganic Syntheses. Inorganic Syntheses. Vol. 5. pp. 113–116. doi:10.1002/9780470132364.ch30. ISBN 978-0-470-13236-4. {{cite book}}: ISBN / Date incompatibility (help) 978-0-470-13236-4 ↩

3. Rowe, Richard A.; Jones, Mark M. (1957). "Vanadium(IV) Oxy(acetylacetonate)". Inorganic Syntheses. Inorganic Syntheses. Vol. 5. pp. 113–116. doi:10.1002/9780470132364.ch30. ISBN 978-0-470-13236-4. {{cite book}}: ISBN / Date incompatibility (help) 978-0-470-13236-4 ↩

4. Itoh, Takashi; Jitsukawa, Koichiro; Kaneda, Kiyotomi; Teranishi, Shiichiro (1979). "Vanadium-catalyzed epoxidation of cyclic allylic alcohols. Stereoselectivity and stereocontrol mechanism". Journal of the American Chemical Society. 101 (1): 159–169. Bibcode:1979JAChS.101..159I. doi:10.1021/ja00495a027. /wiki/Journal_of_the_American_Chemical_Society ↩

5. Rossiter, Bryant E.; Wu, Hsyueh-Liang; Hirao, Toshikazu (2007-03-15). "Vanadyl Bis(acetylacetonate)". Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons. doi:10.1002/047084289X.rv003m.pub2. ISBN 978-0-471-93623-7. 978-0-471-93623-7 ↩

6. Mehdi, Mohamad Z.; Srivastava, Ashok K. (2005). "Organo-vanadium compounds are potent activators of the protein kinase B signaling pathway and protein tyrosine phosphorylation: Mechanism of insulinomimesis". Archives of Biochemistry and Biophysics. 440 (2): 158–164. doi:10.1016/j.abb.2005.06.008. PMID 16055077. /wiki/Archives_of_Biochemistry_and_Biophysics ↩

7. Mehdi, Mohamad Z.; Srivastava, Ashok K. (2005). "Organo-vanadium compounds are potent activators of the protein kinase B signaling pathway and protein tyrosine phosphorylation: Mechanism of insulinomimesis". Archives of Biochemistry and Biophysics. 440 (2): 158–164. doi:10.1016/j.abb.2005.06.008. PMID 16055077. /wiki/Archives_of_Biochemistry_and_Biophysics ↩