Organic Letters
Letter
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N- alkylation reaction. Thus, the dehydrogenative annulation
between 2-aminobenzyl alcohol and phenylacetonitrile fol-
lowed by the N-alkylation reaction with benzyl alcohol were
examined in the presence of cat. 1. Gratifyingly, a 61% yield of
the desired N-(4-methoxybenzyl)-3-phenylquinolin-2-amine
was isolated after column chromatography. Next, a wide
range of 2-(alkylamino)quinolines 9a−9i were synthesized as
summarized in Scheme 3. To the best of our knowledge, the
first Mn-catalyzed one-pot sequential dehydrogenative annu-
lation and N-alkylation reaction to synthesize 2-alkylamino-
quinolines have been achieved.
In conclusion, we report the first sustainable synthesis of
quinazoline and 2-aminoquinoline through dehydrogenative
annulation of 2-aminobenzyl alcohol with nitriles using a well-
defined Mn(I) pincer complex. The reaction proceeds via
dehydrogenation and concomitant formation of C−C and C−
N bond with high atom economy. Furthermore, the synthesis
of 2-(alkylamino)quinolines was achieved through sequential
dehydrogenative annulation and N-alkylation reaction with
alcohols. The structural importance of the obtained com-
pounds and the use of nontoxic, earth-abundant Mn metals
make this approach attractive and sustainable.
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ASSOCIATED CONTENT
* Supporting Information
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1
H NMR and 13C NMR spectra of all compounds; X-
ray crystallographic data for 8e, 8f, 8h, and 8p (PDF)
Accession Codes
tallographic data for this paper. These data can be obtained
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
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AUTHOR INFORMATION
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Corresponding Author
ORCID
(15) (a) Sklyaruk, J.; Borghs, J. C.; El-Sepelgy, O.; Rueping, M.
Angew. Chem. 2019, 131, 785−789. (b) Papa, V.; Cabrero-Antonino,
J. R.; Alberico, E.; Spanneberg, A.; Junge, K.; Junge, H.; Beller, M.
Chem. Sci. 2017, 8, 3576−3585. (c) Fu, S.; Shao, Z.; Wang, Y.; Liu, Q.
J. Am. Chem. Soc. 2017, 139, 11941−11948. (d) Espinosa-Jalapa, N.
A.; Kumar, A.; Leitus, G.; Diskin-Posner, Y.; Milstein, D. J. Am. Chem.
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2017, 129, 4293−4297. (f) Chakraborty, S.; Das, U. K.; Ben-David,
Y.; Milstein, D. J. Am. Chem. Soc. 2017, 139, 11710−11713.
(g) Zhang, G.; Irrgang, T.; Dietel, T.; Kallmeier, F.; Kempe, R.
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Trivelli, X.; Capet, F. d. r.; Paul, J.-F. o.; Dumeignil, F.; Gauvin, R. g.
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Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We are grateful to SERB, DST (ECR/2016/000108), and
DST-INSPIRE (IFA-14-CH-143) for financial support. We
acknowledge the Department of Chemistry and the CIF, IIT-
Guwahati, for the instrumental support and startup grant. K.D.,
A.M., and D.P. are thankful to IITG for their fellowships.
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