Reactions of ethoxycarbonylmethylene(triphenyl)phosphorane with some ortho-quinones in the presence of triphenylphosphine, alcohols and acetic anhydride

Antioxidants and Inflammatory Disease: Synthetic and Natural Antioxidants with Anti-Inflammatory Activity

“…Fylaktakidou and co-workers [72] reported the synthesis and evaluation of fused 1,3-dioxolocoumarins as antioxidants and anti-inflammatory agents. These compounds were synthesized according to Scheme 3 and 4 in connection to their previous work on the synthesis of coumarin derivatives [73][74][75][76][77][78][79]69] and based on their recent studies on the synthesis and biological activities of 4-substituted coumarins with a heterocyclic ring [69][70][71][72]80], which were found to possess significant antiinflammatory and antioxidant activities, as well as inhibition of soybean lipoxygenase.…”

Synthesis and biological evaluation of new benzo[f]furo[2,3‐h]‐and benzo[f]pyrano[2,3‐h]coumarin derivatives.

“…Intramolecular Hoffman elimination of triphenylphosphine from 9 leads to the o-hydroxyarylbutenodioate 10, which through -lactonization gives the obtained coumarins 2, 3, 7. It is interesting to mention that no -lactonization products 11 were isolated as profoundly [20] the favored conformation and configuration of the o-hydroxyarylbutenedioic ester 10 favor the -lactonization.…”

The reaction of Wittig and Wittig-Horner reagents with dicyanomethylene derivatives of fluorenone, xanthone, and thiaxanthone. A novel synthesis of phosphoranylidenecyclobutylidene derivatives

“…Adducts 6a and 6b can be obtained via 1:1 addition of the ylides 1a or 1b on the more electrophilic and less sterically hindered methide carbon to give betaine (A). It may be considered that the phosphoranylidenecyclobutane intermediates (B) are formed via the expulsion of a suitable moiety (i.e., RH, R‫ס‬OCH 3 , or OC 2 H 5 ) followed by addition of a second molecule of ylide 1 to yield the phosphoranylidenecyclobutylidene adducts 6a and 6b along with triphenylphosphine oxide [26].…”