Issue in Honor of Prof. Lutz F. Tietze ARKIVOC 2007 (v) 231-242
Synthesis of novel 3-arylcyclopenta[c]quinolines via acid-induced domino cyclization of 2-arylamino-2-methylthioethenyl 2-arylcyclopropyl ketones
S. K. S. Yadav, A. K. Yadav, G. S. M. Sundaram, H. Ila,* and H. Junjappa Department of Chemistry, Indian Institute of Technology, Kanpur-208016, India E-mail: hila@iitk.ac.in
Dedicated to Professor Lutz F. Tietze on his 65th birthday
Abstract A novel acid-induced domino cyclization of N,S-anilinoacetals of type 3 derived from 2arylcyclopropyl ketones, is reported which yields a wide range of substituted- and fused- 3- arylcyclopenta[c]quinolines 6 with concomitant formation of a cyclopentane and a quinoline ring.
Keywords: Domino cyclization, cyclopenta[c]quinolines, N,S-anilinoacetals
Introduction
Substituted quinolines and their benzo- or hetero- fused analogues represent an important class of heterocyclic compounds because of their presence in numerous biologically active natural products, along with the wide spectrum of physiological activities displayed by these class of compounds.1,2 As a consequence, much attention has been focused towards developing new synthetic methods for substituted- and fused quinolines.1,3 Domino reactions are of growing interest in synthetic organic chemistry because they allow rapid construction of polycyclic structures in a single operation and confer great strategic value in molecular construction.4 Our own interest in this regard has been concerned with the elaboration of domino reactions involving acid-induced rearrangements of 2-aryl-(or heteroaryl-)cyclopropyl ketones with an a( bismethylthio)-methylene functionality as the cationic cyclization terminator, which yield a range of carbocyclic products such as substituted cyclopentanones,5a,b cyclopenta[b]indanes,5c–d diquinanes,5d 1-arylindanes,5e bicyclo[3.2.1]octene,5f and other cyclopentano-fused heterocycles.5g–i In continuation of these studies, we now report the domino carbocationic cyclization of arylcyclopropyl ketones of type 3 carrying an (N,S-aminomethylene) functionality, yielding 3- arylcyclopenta[c]quinolines (compound 6) in a single one-pot operation.
ISSN 1424-6376 Page 231 ©ARKAT USA, Inc.
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