<b>Solvent-free synthesis of xanthene derivatives by Preyssler type heteropolyacid</b>

Abstract

Dimedone reacted with aromatic aldehydes and 3,4-methylenedioxyphenol or β-naphthol in the presence of a catalytic amount of Preyssler type heteropolyacid, H14[NaP5W30O110], as a green and reusable catalyst under solvent-free conditions to form a variety of new xanthene derivatives in very good yields.

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

“…8,11,16,17,19,23 The protocols using microwave radiation lasted less than 5-15 min; 15,18,22 however, these methodologies have disadvantages such as the need to prepare the catalysts, 18,22 the use of detrimental metals as catalysts, 15,22 and the use of toxic solvents to purify the desirable products. 15 Our protocol takes only a few minutes to complete the reaction, uses a cheap, eco-friendly and user-friendly catalyst and all the xanthenones were purified by recrystallization.…”

“…3,11,14,15,20 Although this nucleophilic addition is reasonable, there is no discussion about the regioselectivity of the intermediate. Also, to the best of our knowledge, there are no theoretical and/or experimental studies about the mechanism proposition in the literature.…”

“…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. 13,16,17,20 A readily available and non-hazardous catalyst that promotes the formation of xanthenones in a short reaction time, under solvent-free condition, and simple work-up is highly desirable.…”

Two ligand oxidio-vanadium(IV) complexes as novel efficient catalysts in multicomponent reactions for synthesis of tetrahydrobenzopyran derivatives

“…More than ever, the industry requests organic chemists the expansion of new strategies and technologies, to gain novel compounds in a fast, convergent and efficient way. One of the most attractive apparatus in modern organic chemistry is the use of multicomponent reactions (MCRs), which combine in one-pot at least three simple building blocks, provide a most powerful to make functionalized compounds [1][2][3][4][5][6][7]. MCRs as efficient and effective methods are considered a vital technique in the synthesis of many important heterocyclic compounds such as tetrahydrobenzopyran derivatives nowadays.…”

Antioxidant, Antimicrobial and Antiproliferative Activities of Synthesized 2,2,5,5-Tetramethyl-9-aryl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione Derivatives

“…A wide variety of methods for the preparation of the xanthenes have been reported. [6][7][8][9][10][11] Antioxidants are necessary to control degenerative reactions produced by reactive oxygen and nitrogen species. These species are involved in several ailments including cancer, heart diseases and Alzheimer's disease.…”