azad hossain - Academia.edu (original) (raw)
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Indian Institute of Chemical Technology
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Papers by azad hossain
Organic Letters, 2004
The first practical and economical process for synthesis of 2,3-disubstituted indole compounds ha... more The first practical and economical process for synthesis of 2,3-disubstituted indole compounds has been developed with high regioselectivity by palladium-catalyzed indolization of 2-bromo-or chloroanilines and their derivatives with internal alkynes. The indole nucleus is a prominent structural motif abundantly found in numerous natural products and pharmaceutically active compounds. 1 Many methods have been developed to meet the need of building indole structures. 2 However, regioselective formation of 2,3-disubstituted indoles is challenging with these classical approaches. The recently developed palladium-catalyzed indolization method by Larock et al. 3 provided a solution to the aforementioned issues of regioselectivity, and has been widely applied to preparation of heterocycles. 4 This versatile "ligandless" heteroannulation of internal alkynes with 2-iodoanilines allows easy access to a variety of indoles that may not be available by conventional methods in terms of substitution and functionality (eq 1). Inspired by Larock's work, we were interested in exploring the possibility of replacing the iodoanilines with the much cheaper 2-bromo or 2-chloro derivatives. If such a transformation were feasible, it would be of significant practical and economical value from a cost and throughput
Organic Letters, 2004
The first practical and economical process for synthesis of 2,3-disubstituted indole compounds ha... more The first practical and economical process for synthesis of 2,3-disubstituted indole compounds has been developed with high regioselectivity by palladium-catalyzed indolization of 2-bromo-or chloroanilines and their derivatives with internal alkynes. The indole nucleus is a prominent structural motif abundantly found in numerous natural products and pharmaceutically active compounds. 1 Many methods have been developed to meet the need of building indole structures. 2 However, regioselective formation of 2,3-disubstituted indoles is challenging with these classical approaches. The recently developed palladium-catalyzed indolization method by Larock et al. 3 provided a solution to the aforementioned issues of regioselectivity, and has been widely applied to preparation of heterocycles. 4 This versatile "ligandless" heteroannulation of internal alkynes with 2-iodoanilines allows easy access to a variety of indoles that may not be available by conventional methods in terms of substitution and functionality (eq 1). Inspired by Larock's work, we were interested in exploring the possibility of replacing the iodoanilines with the much cheaper 2-bromo or 2-chloro derivatives. If such a transformation were feasible, it would be of significant practical and economical value from a cost and throughput