Sulfonic acid-functionalized mesoporous silica nanoparticles (SAMSNs): a recoverable heterogeneous acid catalyst for green synthesis of dicoumarols Ebrahim Mehrasbi • Yaghoub Sarrafi • Amir Vahid • Heshmatollah Alinezhad Received: 24 October 2013 / Accepted: 25 February 2014 Ó Springer Science+Business Media Dordrecht 2014 Abstract Sulfonic acid-functionalized mesoporous silica nanoparticles (SAMS- Ns) have been used as a highly efficient and recoverable heterogeneous acid catalyst for green synthesis of dicoumarols by reaction of different aldehydes with 4-hy- droxycoumarin in aqueous media. High to excellent yields were obtained. This mesoporous catalyst is readily recovered and can be reused at least six times without significant loss of its catalytic activity. Keywords Green synthesis Á Dicoumarols Á 4-Hydroxycoumarin Á Sulfonic acid-functionalized mesoporous silica Á Aqueous medium Introduction Coumarins constitute a prominent class of organic compounds utilized in the cosmetics, food, pharmaceutical, and agrochemical industries [1–3]. Among the coumarin derivatives, dicoumarols have attracted much attention because of their biological importance and wide-ranging pharmacological activity, for example anticoagulant, antitumor, antihelminthic, insecticidal, hypnotic, antifungal, and HIV protease inhibitory activity [3–12]. Dicoumarol, 3,3 0 -methylenebis(4-hydroxycoum- arin), a naturally occurring anticoagulant drug that functions as a vitamin K antagonist, was first isolated from sweet clover (Melilotus alba and Melilotus officinalis)[13, 14]. Neodymium(III) and lanthanum(III) complexes of dicoumarol have substantial cytotoxic activity [15]. Notably, clinical trials have revealed that E. Mehrasbi Á Y. Sarrafi (&) Á A. Vahid Á H. Alinezhad Department of Organic Chemistry, Faculty of Chemistry, University of Mazandaran, 47416 Babolsar, Iran e-mail: ysarrafi@umz.ac.ir 123 Res Chem Intermed DOI 10.1007/s11164-014-1578-9