Poly(4-vinylpyridinium) perchlorate as an efficient and recyclable catalyst for the synthesis of biscoumarins and bisindoles

Recent Advances in the Synthesis of Biscoumarin Derivatives

“…A variety of aromatic, aliphatic, and heterocyclic aldehydes reacted with 4‐hydroxy coumarin under optimized reaction conditions to give the corresponding biscoumarins in high yields and short reaction times. Furthermore, the catalytic activity of P(4‐VPH)ClO 4 did not reduce significantly after at least five runs (Table , entry 6) …”

“…Furthermore, the catalytic activity of P(4-VPH)ClO 4 did not reduce significantly after at least five runs (Table 1, entry 6). 24 Tabatabaeian et al synthesized bis-(4-hydroxycoumarin)methanes with different amounts of RuCl 3 ċnH 2 O (2-15 mol%), different solvents, and different temperatures (25-100 C). Finally, the optimized reaction condition with 5 mmol% (10.7 mg) of the catalyst in water at 80 C led to the products in 23-35 min with 75-95% 18 37 Zn(proline) 2 5 mol% H 2 O R e flux 5-9 min 91-96 10 51…”

[PVP‐SO3H] HSO4: An Efficient Polymeric Solid Acid Catalyst for the Formylation and N‐Boc Protection Reactions

“…The heterogeneous solid acid catalysts play as the main practical constituents in the industrial processes . These types of catalysts have some advantages with regard to the homogeneous Brönsted acidic catalysts such as: easy production and separation, high surface area, low cost and energy saving, being non‐toxic and non‐corrosive, high resistance in washing, the low cost of waste discarding and creating low hazard for the environment, performing the reaction in mild conditions and decreasing the reaction steps …”