4
Tetrahedron
isolate intermediates from the reaction of 7a and 2a by lowering
Research Fund (DBG5480018), the Center of Excellence for
Innovation in Chemistry (PERCH-CIC), the Commission on
Higher Education (CHE), the Ministry of Education, the
Department of Chemistry, and the Faculty of Science, Kasetsart
University. The authors thank the Chulabhorn Research Institute
for providing high-resolution mass spectra.
the reaction temperature (Scheme 6). When the reaction was
carried out at 70 ºC, we were able to isolate only intermediate 16.
In addition, when this intermediate was subjected to the same
reaction conditions we typically performed to prepare indolo[1,2-
a]quinolines, product 9a was obtained. This is strong evidence in
support of the condensation taking place first in the cascade
process. However, it is also possible that intermediate 15 also
formed and we were just not able to isolate it.
Supplementary Material
Experimental procedures and characterization data for 7-10
(except those not isolated), 14, 16, 18 and 19 are available at……
References and Notes
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Scheme 6. Attempt to isolate reaction intermediates.
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cyclization (Scheme 7). In this reaction, compound 18 would be
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Scheme 7. Nucleophilic aromatic substitution and Knoevenagel
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Acknowledgments
Financial support was provided by the Kasetsart University
Research and Development Institute (KURDI), the Thailand
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