* Corresponding author. E-mail address: nsboukhris@yahoo.com (S. Boukhris) © 2015 Growing Science Ltd. All rights reserved. doi: 10.5267/j.ccl.2016.4.001 Current Chemistry Letters 5 (2016) 99–108 Contents lists available at GrowingScience Current Chemistry Letters homepage: www.GrowingScience.com Snail shell as a new natural and reusable catalyst for synthesis of 4H-Pyrans derivatives Zakaria Benzekri a , Houdda Serrar a , Said Boukhris *a , Brahim Sallek b and Abdelaziz Souizi a a Laboratory of Organic Chemistry, Organometallic and Theoretical. Faculty of Sciences, Ibn Tofaïl University, BO 133, 14000 Kenitra, Morocco b Laboratoire d’Agroressources et Génie des Procédés. Faculté des Sciences, Université Ibn Tofaïl, 14000 Kenitra, Morocco C H R O N I C L E A B S T R A C T Article history: Received October 21, 2015 Received in revised form December 20, 2015 Accepted 7 April 2016 Available online 7 April 2016 A simple, efficient and general method for the synthesis of 4H-pyrans is established through a multi component cyclocondensation of aromatic aldehydes, malononitrile and ethyl acetoacetate or acetyl acetone using snail shell as a natural catalyst. In this method the snail shell was used as green and reusable natural catalyst. Excellent yields, short reaction times and availability of the catalyst are the advantages of this method. © 2016 Growing Science Ltd. All rights reserved. Keywords: Heterogeneous catalysis 4H-pyrans Snail shell Natural catalysts Green catalysts 1. Introduction Compared with classical methods, the heterogeneous catalysis solid-liquid has been shown to have desirable effects on reactions performance such as: good yields, short reaction times, easier work-up procedure, formation of pure products in milder conditions and waste minimization. In addition, introduction of clean procedures utilizing eco-friendly green catalysts has attracted great attention of workers. 1 Thus, development of a mild, inexpensive, and reusable catalyst for synthesis of organic compounds, still remains an attractive goal for researchers. 4H-Pyran derivatives occupy an important place in the realm of synthetic organic chemistry because of their biological and pharmacological properties as anticancer, 2 cytotoxic, 3 anti-HIV, 4-6 anti-inflammatory, 7 anti-malarial, 8-9 antimicrobial, 10 antihyperglycemic and antidyslipidemic. 11 In addition, these compounds are a common structural unit in a number of natural products. 12-14