ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Phospho sulfonic acid as efficient heterogeneous Brønsted acidic catalyst for one-pot synthesis of 14H-dibenzo[a,j ]xanthenes and 1,8-dioxo-octahydro-xanthenes

Sobhan Rezayati, Zahra Erfani, and Rahimeh Hajinasiri

Chemistry Department, Qaemshahr Branch, Islamic Azad University, PO BOX 163, Qaemshahr, Iran

E-mail: rhmhajinasiri@yahoo.com

Abstract: A simple, efficient procedure for the preparation of phospho sulfonic acid PO(OSO₃H)₃ as a Brønsted acidic and recoverable heterogeneous catalyst is described, used for the one-pot synthesis of aryl-14H-dibenzo[a,j ]xanthenes and 1,8-dioxo-octahydro-xanthenes. A cost-effective, simple and convenient procedure for the synthesis of aryl-14H-dibenzo[a,j]xanthenes was developed via a onepot condensation from substituted benzaldehydes and β-naphthol under solvent-free conditions. The one-pot condensation of substituted benzaldehydes and 5,5-dimethyl-1,3-cyclohexanedione (dimedone) under solvent-free conditions leads to 1,8-dioxo-octahydro-xanthenes. These protocols afford a number of advantages, such as: excellent yields, very short reaction times, easy procedure, simple methodology and ease of preparation and regeneration of the catalyst.

Keywords: phospho sulfonic acid – Brønsted acidic catalyst – aryl-14H-dibenzo[a,j ]xanthenes – 1,8- dioxo-octahydro-xanthenes – solvent-free conditions – reuse of catalyst

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0058

Chemical Papers 69 (4) 536–543 (2015)