Chemistry:Dihydrophenanthrenes
Dihydrophenanthrenes are a group of chemical compounds structurally derived from phenanthrene. They are formed by partial hydrogenation of the phenanthrene backbone, in which a double bond of the aromatic system is saturated with hydrogen atoms. The backbone belongs to the family of polycyclic aromatic hydrocarbons (PAHs).
Structure
Phenanthrene consists of three fused benzene rings. In dihydrophenanthrenes, part of the aromaticity is lost because two hydrogen atoms are added to adjacent carbon atoms of one ring. This results in a partially hydrogenated ring system with modified physicochemical properties.
Examples include:
- 9,10-dihydrophenanthrene
- 1,2-dihydrophenanthrene
Stability, reactivity, and melting point vary significantly depending on the position of hydrogenation.
Properties
Dihydrophenanthrenes are mostly colorless to slightly yellowish crystalline solids.[1] They are poorly soluble in water but dissolve well in organic solvents such as chloroform, dichloromethane, petroleum ether, ethyl acetate, and acetone.[2] Due to the partial loss of aromaticity, they are more reactive than phenanthrene itself.
Occurrence
Dihydrophenanthrenes occur infrequently in nature, but they can be found as intermediates in the biosynthesis of phenanthrene derivatives, particularly in orchids (e.g., in the genus Dendrobium). Known compounds include orquinol and hircinol.[3][4]
Synthesis
Dihydrophenanthrenes can be synthesized by catalytic hydrogenation of phenanthrene, by reduction reactions of phenanthrene derivatives, or by acetyltrimethylsilane-mediated synthesis.[5][6][7][8] 4a,4b-Dihydrophenanthrenes are colored, unstable conjugated polyene compounds obtained photochemically by irradiation of the corresponding cis-1,2-diarylethylenes.[9]
Use
Some dihydrophenanthrene derivatives are used in organic synthesis, pharmaceutical research, and as precursors of natural alkaloids. Their structural features also play a role in research on phenanthrene-based drugs.[10]
References
- ↑ "tcichemicals.com: CAS RN: 776-35-2 |; 9,10-Dihydrophenanthrene". https://www.tcichemicals.com/DE/en/p/D0554. "Specifications & Properties: Appearance White or Colorless to Light orange to Yellow powder to lump to clear liquid"
- ↑ "Bioactive dihydrophenanthrenes from plants", Studies in Natural Products Chemistry, Studies in Natural Products Chemistry (Elsevier) 74: 117–164, 2022, doi:10.1016/b978-0-323-91099-6.00002-5, ISBN 978-0-323-91099-6, https://linkinghub.elsevier.com/retrieve/pii/B9780323910996000025, retrieved 2025-11-19
- ↑ K. H. Fritzemeier, H. Kindl (1983-07-01), "9,10-Dihydrophenanthrenes as phytoalexins of Orchidaceae. Biosynthetic studies in vitro and in vivo proving the route from L-phenylalanine to dihydro-m-coumaric acid, dihydrostilbene and dihydrophenanthrenes", European Journal of Biochemistry 133 (3): 545–550, doi:10.1111/j.1432-1033.1983.tb07498.x, PMID 6861741
- ↑ Natale Badalamenti, Sabino Russi, Maurizio Bruno, Viviana Maresca, Alessandro Vaglica, Vincenzo Ilardi, Anna Zanfardino, Michela Di Napoli, Mario Varcamonti, Piergiorgio Cianciullo, Giovanni Calice, Simona Laurino, Geppino Falco, Adriana Basile (2021), "Dihydrophenanthrenes from a Sicilian Accession of Himantoglossum robertianum (Loisel.) P. Delforge Showed Antioxidant, Antimicrobial, and Antiproliferative Activities", Plants 10 (12): 2776, doi:10.3390/plants10122776, PMID 34961247
- ↑ D. Muriel Hall, Mary S. Lesslie, E. E. Turner (1950), "143. 9 : 10-Dihydrophenanthrenes. Part I. The formation of 9 : 10-dihydrophenanthrene from 2 : 2′-disubstituted diphenyls", Journal of the Chemical Society (Resumed): 711–713, doi:10.1039/JR9500000711
- ↑ Minoru Tamiya, Corinna Jäger, Ken Ohmori, Keisuke Suzuki (2007), "Stereoselective Access to Functionalized Dihydrophenanthrenes via Reductive Cyclization of Biaryl Ene-Aldehydes", Synlett 2007 (5): 0780–0784, doi:10.1055/s-2007-970771
- ↑ Ramendra Pratap, Vishnu Ji Ram (2007), "Acetyltrimethylsilane mediated synthesis of dihydrophenanthrenes", Tetrahedron Letters 48 (36): 6318–6320, doi:10.1016/j.tetlet.2007.07.014
- ↑ Ana Milián, Patricia García-García, Adrián Pérez-Redondo, Roberto Sanz, Juan J. Vaquero, Manuel A. Fernández-Rodríguez (2020), "Selective Synthesis of Phenanthrenes and Dihydrophenanthrenes via Gold-Catalyzed Cycloisomerization of Biphenyl Embedded Trienynes", Organic Letters 22 (21): 8464–8469, doi:10.1021/acs.orglett.0c03067, PMID 32969663
- ↑ Karol A. Muszkat (1980), "The 4a,4b-Dihydrophenanthrenes", Organic Chemistry Syntheses and Reactivity, Topics in Current Chemistry, 88, Berlin, Heidelberg: Springer, pp. 89–143, doi:10.1007/BFb0048505, ISBN 978-3-540-38970-5
- ↑ Liangliang Yao, Bo Fang, Qiong Hu, Yu Lei, Li Bao, Yimin Hu (2020), "Phenanthrenes/dihydrophenanthrenes: the selectivity controlled by different benzynes and allenes", Chemical Communications 56 (96): 15185–15188, doi:10.1039/D0CC06300B, ISSN 1364-548X, PMID 33216071, https://pubs.rsc.org/en/content/articlelanding/2020/cc/d0cc06300b
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