Total Synthesis of Munchiwarin, a Triprenylated Chalcone from Crotalaria medicagenia

Abstract

An efficient method is developed for the synthesis of the modified triprenylated chalcone, munchiwarin (1), isolated from the roots of Crotalaria medicagenia. The synthesis of 1 utilizes a Claisen-Schmidt condensation between 2,4-dihydroxy-3,5-C-diprenyl acetophenone and 4-methoxy benzaldehyde in the presence of Ba(OH)2 to yield the unusual chalcone 5 that contains a nine-membered ether ring. Further prenylation of 5 with 1-bromo-3-methylbut-2-ene and its subsequent demethylation with BBr3 gave munchiwarin (1).

1-(4-Aminophenyl)-3-[2-(trifluoromethyl)phenyl]prop-2-en-1-one

“…For related structures, see: Narender et al (2007); Kamal et al (2008); Wu et al (2009); Low et al (2002); Yathirajan et al (2006); Suwunwong et al (2009). For background to and applications of chalcones, see: Heidari et al (2009); Nielsen et al (2005); Mojzis et al (2008); Achanta et al (2006); Dimmock et al (1999); Liang et al (2007aLiang et al ( ,b, 2009; Zhao et al (2010).…”

“…Due to the broad spectrum of biological activities of this type of compounds, various chalcone analogues have been synthesized in order to filter the better ones or the unique ones (Narender et al, 2007;Kamal et al, 2008). As a continuation of our broad program of work on the synthesis and structural study of chalcones, the title chalcone derivative has been obtained and an X-ray diffraction study was carried out.…”

(E)-3-[3,4-Bis(methoxymethoxy)phenyl]-1-(7-hydroxy-5-methoxy-2,2-dimethylchroman-8-yl)prop-2-en-1-one

“…Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2010). Chalcones or 1,3-diphenyl-2-propen-1-one derivatives flavonoids consist of two aromatic rings that are linked by a threecarbon α, β-unsaturated carbonyl unit (Avila et al, 2008;Reddy et al, 2010), and key precursors for the synthesis of a various flavonoids, some of which are components in food (Narender et al, 2007). We intend to use the intensely-orange title compound, (I), in the synthesis of other compounds.…”

“…For background to chalcones, see: Avila et al (2008); Narender et al (2007); Reddy et al (2010). Hydrogen-bond geometry (Å , ).…”

Efficient Catalytic Performance of Calcined Tungstophosphoric Acid for the Claisen-Schmidt Condensation under Solvent-Free Reaction

“…Conventionally, Claisen-Schmidt condensation is carried out in the presence of acid or base catalysts between aromatic aldehydes and ketones. Numerous catalysts have been used so far for the synthesis of chalcones in bases such as NaOH [26], KOH [27], LiOH•H2O [28], Ba(OH)2 [29] and in acids such as dry HCl [30], RuCl3 [31], TiCl4 [32], sulfonic acids [33], ionic liquids [4] and clay [34]. These mentioned catalysts have many shortcomings such as toxicity, corrosiveness, long reaction times, generation of undesired products and high temperature.…”