title: N-Sulfonic acid poly(4-vinylpyridinium) hydrogen sulfate as an efficient and reusable solid acid catalyst for one-pot synthesis of xanthene derivatives in dry media under ultrasound irradiation.
abstract: N-Sulfonic acid poly(4-vinylpyridinium) hydrogen sulfate catalyzed efficiently the synthesis of xanthene derivatives under ultrasonic irradiation at room temperature, which has prompted various concerns involving cost and environmental persistence. This methodology shows the effect of presence of anion hydrogen sulfate as an important and effective factor on the promotion of the one-pot multi-components and condensation reactions. The catalyst can be recovered by simple filtration and used for several times without a significant loss of catalytic activity.
authors.affiliation: Research House of Professor Reza, Education Guilan, District 1, Rasht 41569-17139, Iran. Electronic address: ngkhaligh@guilan.ac.ir.
authors.forename: Nader Ghaffari
authors.initials: NG
authors.lastname: Khaligh
authors.affiliation: Department of Chemistry, College of Science, University of Guilan, Rasht 41335-19141, Iran.
authors.forename: Farhad
authors.initials: F
authors.lastname: Shirini
keywords: Anion effect; Heterogeneous catalyst; Multi-component; Ultrasound; Xanthene