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Synthesis 2005(13): 2161-2170  
DOI: 10.1055/s-2005-870004
PAPER
© Georg Thieme Verlag Stuttgart · New York

The tert-Amino Effect in the Synthesis of Hetaryl- and Arylsulfonyl-Substituted Pyrrolo- and Pyrido[1,2-a]quinoline Derivatives and their Pyrazolo Annulated Analogues

Anton V. Tverdokhlebov*a, Alexander P. Gorulyaa, Andrey A. Tolmachevb, Alexander N. Kostyukc, Alexander N. Chernegac, Eduard B. Rusanovc
a Enamine Ltd., Alexandra Matrosova str. 23, 01103, Kiev, Ukraine
e-Mail: atver@univ.kiev.ua;
b Kiev National Taras Shevchenko University, Volodimirska str. 62, 01033, Kiev, Ukraine
c Institute of Organic Chemistry NAS, Murmanskaya str. 5, 02094, Kiev, Ukraine
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Publication History

Received 3 February 2005
Publication Date:
07 July 2005 (online)

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Abstract

4-Hetaryl and 4-tosyl-1,2,3,3a,4,5-hexahydropyrrolo[1,2-a]quinoline-4-carbonitriles were prepared in two steps by the condensation of 2-(1-pyrrolidinyl)benzaldehydes with substituted acetonitriles XCH2CN (X = hetaryl, tosyl), followed by the thermal cyclization of the corresponding arylidene derivatives. Similarly, starting from 2-(1-piperidinyl)benzaldehydes 5-hetaryl and 5-tosyl-2,3,4,4a,5,6-hexahydro-1H-pyrido[1,2-a]quinoline-5-carbonitriles were obtained. For the hetaryl-substituted derivatives the cyclization step was found to be assisted by protons. In addition 4,5,5a,6,7,8-hexahydro-1H-pyrazolo[3,4-e]indolizine and 1,4,5,5a,6,7,8,9-octahydro-pyrazolo[4,3-c]quinolizine derivatives were prepared by the same method starting from 5-(1-pyrrolidinyl)- and 5-(1-piperidinyl)-3-methyl-1-phenylpyrazole-4-carbaldehydes. The relative configuration between the bridgehead hydrogen and the cyano group was assigned as trans on the basis of x-ray crystallographic data.

Key words

heterocycles - pyrazolo[3,4-e]indolizines - pyrazolo[4,3-c]quinolizines - pyrrolo[1,2-a]quinolines - ring closure