pTSA-catalyzed one-pot synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones in ionic liquid and neat conditions

H4SiW12O40 Catalyzed One‐Pot Synthesis of 12‐Aryl‐8,9,10,12‐tetrahydrobenzo[a] Xanthen‐11‐ones Under Solvent‐Free Conditions

“…The solid product was purified by recrystallization from EtOH to afford the pure product. All compounds are known and their physical and spectroscopic data were in good agreement with those of authentic samples [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] .…”

“…Tetrahydroxanthenone derivatives are generally synthesized by the three-component condensation of 2-naphthol, aryl aldehydes and cyclic 1,3-dicarbonyl compounds under different conditions. There are several reports for the synthesis of 12-aryl-8,9,10,12-Tetrahydrobenzo [a]xanthen-11-ones using catalysts such as NaHSO 4 .SiO 2 10 , Strontium triflate 11 , pTSA 12 , Indium(III) chloride or P 2 26 . However, in spite of their potential utility, some of these methods suffer drawbacks such as the use of toxic and hazardous solvents, unsatisfactory product yields, expensive catalyst, requirement of huge amounts of catalyst, purification of the products by column chromatography and prolonged reaction times.…”

Natural Organic Acid as Green Catalyst for Xanthenones Synthesis: Methodology, Mechanism and Calcium Channel Blocking Activity

“…6 The literature describes the synthesis of xanthenones via a multicomponent reaction using a phenolic compound, an aldehyde, and a cyclic 1,3-dicarbonyl compound. 7 Many Lewis or Brönsted acids may be used as catalysts: calixarenes, 3 ceric ammonium nitrate, 4 polyethyleneglycol bound sulfonic acid, 5 Hy zeolite, 6 triflate proline, 8 tetrabutyl ammonium fluoride, 9 tri-methyl tetradecyl ammonium bromide, 10 sulfamic acid, 11 p-toluenesulfonic acid, 12 triphenylphosphinem-sulfonate/carbon tetrabromide, 13 phosphorus(V) oxide, cumbersome product isolation procedures. 16 They also use expensive and/or detrimental metal precursors, 14,15,22 toxic catalysts, 11,14 and toxic organic solvents to perform the reaction or purify the product.…”

Ultrasound assisted synthesis of tetrahydrobenzo[c]xanthene-11-ones using CAN as catalyst

“…Different catalysts such as sulfamic acid [10], p-TSA [11], selectfluor TM [12], iodine [13], silica sulfuric acid [14], Yb(OTf) 3 [15] and ionic liquids [16] find application in the synthesis of benzo [a]xanthenes. The existing methods have not been conceded for the synthesis of tetrahydrobenzo [c]xanthene-11-ones from a-naphthol (Scheme 1), this is because, the electron density at the b-position of the a-naphthol is not sufficient for the formation of the corresponding ortho-Quinone Methides (o-QMs, Scheme 2) under these conditions.…”