Vapor Phase Synthesis of Annelated Pyridines over Metal Modified Zeolite Beta Arun Kumar Macharla 1 • Mahender Reddy Marri 1 • Swamy Peraka 1 • Naresh Mameda 1 • Srujana Kodumuri 1 • V. V. Krishna Mohan Kandepi 1 • Narender Nama 1 Received: 2 June 2015 / Accepted: 24 July 2015 Ó Springer Science+Business Media New York 2015 Abstract Vapor phase synthesis of annelated pyridines from cyclic ketones, aldehydes and ammonia was carried out over various zeolite molecular sieves like Hb, HZSM-5 (240), HZSM-5 (40), HY, HX, HMCM-41 and Mordenite. The preliminary screening of catalyst clearly shows that Hb catalyst was found to be more active for the vapor phase synthesis of annelated pyridines. Hb was further modified with transition metals like Fe, Cu, Pb, Mo, Zn, Ni, Co, Ce, W and Sn to get higher yields. Graphical Abstract O n R H O NH 3 Zeolite, 350 o C 0.5 h -1 W.H.S.V N n n R + + n = 1/2/3 R = H/Alkyl Keywords Cyclization Á Annelated pyridines Á Heterogeneous catalysis Á Impregnation Á Zeolites 1 Introduction Annelated pyridines and their derivatives are an important class of organic compounds. They provide valuable syn- thetic templates for the preparation of new compounds with specific biological (anti-inflammatory agents [1, 2], anti- bacterial agents [3], inhibitors of gastric acid secretion [4] and calcium channel blockers [5]) or material properties. Octahydroacridines and its derivatives are a class of com- pounds with pharmacological interest [6–9] as illustrated by the preparation of hydrogen-bonding synthetic receptors and polydentate ligands from 1,2,3,4,5,6,7,8-octahy- droacridine (3a) and 9-substituted octahydroacridine derivatives [10]. They also play an important role in the preparation of alkaloids, dyes, drugs and other biologically active compounds with intriguing pharmacological and therapeutic properties [11–13]. 1,2,3,5,6,7-hexahydrodicy- clopenta[b,e] pyridine (3f) is an important anti-ulcer agent [14]. Annelated pyridines are commonly prepared by the condensation of cyclic ketones with an appropriate nitro- gen containing species to build up the pyridine ring. Thus, the Friedlander condensation of cyclopentanone or cyclo- hexanone with b-aminoacrolein affords 2,3-fused pyridines [7]. Conventionally, diannelated pyridines are prepared by the partial hydrogenation of isooxazole over Raney nickel catalyst to b-amino acrolein, further on Friedlander con- densation with cyclopentanone gives 2,3-fused pyridines [15]. bis-Annelated pyridines were synthesized in multi- step by Tabyaoui et al. [16] using cycloalkane carbox- aldehyde-NaN 3 -triphenylphosphines. Pilato et al. elabo- rated a multi-step synthesis of octahydroacridines via condensation of cyclohexanone with formaldehyde [10]. Regas et al. described a multi-step synthesis of 1,2,3,4,5,6,7,8-octahydro-9-methylacridine via an intra- Electronic supplementary material The online version of this article (doi:10.1007/s10562-015-1598-0) contains supplementary material, which is available to authorized users. & V. V. Krishna Mohan Kandepi krizmohan@yahoo.com & Narender Nama narendern33@yahoo.co.in 1 I&PC Division, CSIR-IICT, Hyderabad 500 007, India 123 Catal Lett DOI 10.1007/s10562-015-1598-0