title: Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions.
abstract: A convenient and efficient methodology for the synthesis of densely substituted pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA) as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused isocoumarins were formed in good yields. This synthetic method has several advantages such as the employment of solvent-free reaction conditions without the use of any toxic reagents and metal catalysts, the ease of product isolation, the use of a recyclable catalyst, the low cost, the easy availability of the starting materials, and the excellent yields of products.
authors.affiliation: Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata-700 009, India; ; Tel: +91-33-2484-1647.
authors.forename: Sudipta
authors.initials: S
authors.lastname: Pathak
authors.affiliation: Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata-700 009, India; ; Tel: +91-33-2484-1647.
authors.forename: Kamalesh
authors.initials: K
authors.lastname: Debnath
authors.affiliation: Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata-700 009, India; ; Tel: +91-33-2484-1647.
authors.forename: Animesh
authors.initials: A
authors.lastname: Pramanik
keywords: green chemistry; pyrrole-fused isocoumarin; reusable solid support; silica sulfuric acid; solvent-free condition