SO<sub>4</sub><sup>2-</sup>/SnO<sub>2</sub>-Catalyzed C3-alkylation of 4-hydroxycoumarin with secondary benzyl alcohols and <i>O</i>-alkylation with <i>O</i>-acetyl compounds

Abstract

Sulfated tin oxide (STO) has been found to be an efficient reusable solid superacid catalyst for C3-alkylation and O-alkylation of 4-hydroxycoumarins with benzylic, allylic alcohols/and corresponding acetates respectively, in acetic acid under reflux conditions with good yield of products

Zn(OAc)2.2H2O-Catalyzed C3-alkylation and O-alkylation of 4-Hydroxycoumarin derivatives

“…All synthesized compounds [3a-f and 5a-f] are known and accordingly reference numbers are provided. [23][24][25][26][27][28][29][30][31][32]…”

“…There are a few techniques for C3-alkylating 4-hydroxycoumarin with alcohols that have been documented thus far, including those that use potent acids like HCl, H2SO4, etc. [20][21][22] , Yb(OTf)3 23 , FeCl3.6H2O 24, , Amberlite IR-120 25 , molecular iodine 26 , Bi(OTf)3 27 Fe(ClO4)3.xH2O 28 , TMSOTf 29 , Bi(NO3)3.5H2O/Ionic liquid system 30 , sulphated tin oxide 31 and Ir-Sn bimetallic conventional acid methods 32 , however, are inevitably accompanied by issues such high toxicity, corrosion, catalyst waste, and difficulty in separation and recovery. Some of these catalytic systems have a number of drawbacks, including prolonged reaction durations, a lack of reusability, and low yields.…”

Synthesis of β-amino alcohols by ring opening of epoxides with amines catalyzed by sulfated tin oxide under mild and solvent-free conditions

“…They serve as the foundation for, or are components of, a wide range of industrial goods, such as lubricants, solvents, polymers, fuels, and explosives, as well as pharmaceuticals, petrochemicals, and agrichemicals. [1][2][3][4][5][6][7][8][9][10][11] In synthetic chemistry, the ability to open the rings of epoxides and introduce amino functionality into oxiranes to produce β-amino alcohols is becoming increasingly important. β-amino alcohols are a significant class of chemical molecules with several applications, including the production of unnatural amino acids, 12 chiral auxillaries for asymmetric synthesis, 13 and a wide range of physiologically active natural and synthesized products.…”

Electrochemical capacitor behavior of SO42-/MxOy (M-Fe, Ti, Zr, Sn)

“…Sulfated metal oxides (SO 4 2 À /M x O y ) are a useful group of strong solid acid catalysts. Due to their strong acidity, easy to separate, and recover from the product mixture, they are widely used in catalysis [31][32][33][34]. The ability of solid acid to act as a catalyst is due to the presence of different types of acid sites which provide active surface for the chemical reaction to take place on.…”