Improved Methods of Synthesis of Lignan Arylnaphthalene Lactones via Arylpropargyl Arylpropiolate Esters

Intramolecular Dehydro-Diels–Alder Reaction Affords Selective Entry to Arylnaphthalene or Aryldihydronaphthalene Lignans

“…This reaction afforded a 2:1 mixture of lactones 16 and 17 , consistent with previous DDA reactions of precursors containing heteroatoms, esters, or amides in the styrene-yne tether (Table 1 , entry 1). 15 The potential of this DDA strategy was first recognized by Klemm 16 and others who have validated this approach; 17 , 18 however, low yields, mixtures of naphthalene and dihydronaphthalene products, and mixtures of regioisomers were often obtained. 16 , 19 …”

Lignans from Acanthopanax chiisanensis having an inhibitory activity on prostaglandin E2 production

“…Based on these findings, isolation of compounds were carried out from the chloroform fraction of the roots by silica gel column chromatography, and resulted in isolation of five lignans. Their structures were elucidated as lsesamin (Pelter et al, 1978;Ina et al, 1987), helioxanthin (Stevenson and Weber, 1989), savinin (Banerji et al, 1984;Shieh et al, 1990), taiwanin C (Stevenson and Table 1. Effects of various fractions from the roots on TPAinduced PGE 2 production in rat peritoneal macrophages Treatment PGE 2 (ng/ml) None 2.10 ± 0.04*** TPA 8.48 ± 0.57 TPA + n-Hexane fraction 8.28 ± 0.59 TPA + Chloroform fraction 2.11 ± 0.12*** TPA + Ethyl acetate fraction 3.58 ± 0.33*** TPA + n-Butanol fraction 8.63 ± 0.75…”

Arylnaphthalene lactone analogues: synthesis and development as excellent biological candidates for future drug discovery

“…Briey, compound 39 reacted with a zinc analog to yield 9-amino-6,7-methylenedioxynaphtho[2,3c]furan-1(3H)-one (40). This, upon reaction with sodium nitrite in an aqueous hydrochloric acid, followed by addition of potassium iodide, furnished 9-iodo-6,7-methylenedioxynaphtho[2,3-c]furan-1(3H)-one (41). The Suzuki coupling of compound 41 with benzo[d] [1,3]dioxol-5-yl boronic acid leads to the principle compound taiwanin C (16) (Scheme 6).…”

“…The synthesis of arylnaphthalene lactones bearing aryl ethers or phenolic OHs on a benzene ring was carried out by the Stevenson group using an intramolecular Diels-Alder reaction of 3-arylprop-2-yn-1-yl-3-arylpropiolate or 3-arylprop-2-en-1-yl-3-arylpropiolate. [41][42][43] The Mori group 44 and Anastas group 45,46 have reported the synthesis of arylnaphthalene lactone analogs using Pd and Ag-catalyzed [2 + 2 + 2] cyclization, respectively. The Tanabe group also synthesized arylnaphthalene lactone analogs using the regiocontrolled benzannulation of diaryl(gem-dichlorocyclopropyl)methanols, 47 see Table 1.…”