88051-30-3Relevant articles and documents
Enantioselective Total Syntheses of (R)- A nd (S)-Naphthotectone, and Stereochemical Assignment of the Natural Product
Guerrero-Vásquez, Guillermo A.,Galarza, Flávia A. D.,Molinillo, José M. G.,Andrade, Carlos Kleber Z.,Macías, Francisco A.
supporting information, p. 1599 - 1604 (2016/04/05)
Both isomers of naphthotectone, an isoprenoid quinone from Verbenaceae Tectona grandis possessing interesting biological activities, were enantioselectively obtained by two different synthetic routes in which the carbon side-chain of the naphthoquinone core was introduced using either a Sonogashira or a Heck coupling reaction. In both cases, the naphthoquinone core of the final products was obtained by a late-stage anodic treatment. (R)-Naphthotectone was obtained in six steps from leuconaphthazarin with an overall yield of 38 % and an enantiomeric excess of 86 %. This compound was found to have the same absolute configuration as the natural product at its C-3′ stereogenic center. (S)-Naphthotectone was obtained in five steps from leuconaphthazarin with an overall yield of 36 % and an enantiomeric excess of 80 %. Naphthotectone was synthesized in both racemic and enantioenriched forms by two different synthetic strategies using Pd coupling reactions and anodic treatment as key steps. The stereochemistry of the natural product has been assigned.
A convenient synthesis of 2-formyl-1,8:4,5-bis(methylenedioxy) naphthalene
Zhao, Ai-Hong,Xu, De-Feng,Zhuo, Wen,Rao, Zhen,Li, Shao-Shun
, p. 647 - 648 (2008/09/17)
2,3-Dihydronaphazarin was prepared from 1,4-dimethoxybenzene and dichloromaleic anhydride. Reaction with bromochloromethane gave 1,8:4,5-bis(methylenedioxy)naphthalene which with NBS, gave 2-bromo-1,8:4,5-bis- (methylenedioxy)naphthalene. Reaction of the Grignard derivative with DMF afforded 2-formyl-1,8:4,5-bis(methylenedioxy)naphthalene. This method had several advantages compared with the reported synthesis, including fewer steps, milder condition and higher yields.
Naphtho-1,3-dioxines
Dallacker, Franz,Jacobs, Johannes,Coerver, Wim
, p. 1000 - 1007 (2007/10/02)
Treatment of 1,8-Dihydroxy-naphthaline with bromochloromethane/K2CO3 in DMF gives Naphtho-1,3-dioxine (1a) in good yield.The bromo (1b) and nitro compound (1c) can be obtained free of isomerics by electrophilic substitution of 1a.Bromolithium exchange of 1b leads to a lithium organic compound, which possibles the synthesis of alkyl-, olefinic-, and carboxylic derivatives of the substrate 1a.In a similar way the treatment of 2,3-dihydroxynaphthazarin with chlorobromomethane/K2CO3 gives the naphtho-bis-1,3-dioxine (3a).The substrate 3a can besubjected to electrophilic aromatic substitutions. - Key words: 6-Brom-naphtho-1,3-dioxine, 6-Nitro-naphtho-1,3-dioxine, 4-Methyl-naphthobis-1,3-dioxine-9-carboxylic Acid