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Selective N2-Alkylation of 1H-Indazoles and 1H-Azaindazoles

Jennifer Clemens, Emily L. Bell, Allyn T. Londregan*

*Rare Disease Medicine Design, Pfizer Inc., Eastern Point Road, Groton CT 06340, USA, Email:

J. Clemens, E. L. Bell, A. T. Londregan, Synthesis, 2022, 54, 3215-3226.

DOI: 10.1055/s-0040-1719917

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Either trifluoromethanesulfonic acid or copper(II) triflate promote general and selective procedures for the N2-alkylation of 1H-indazoles and 1H-azaindazoles with various primary, secondary, and tertiary alkyl 2,2,2-trichloroacetimidates to afford the corresponding 2-alkyl-2H-indazoles/azaindazoles.

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Key Words

regioselectivity, 2H-indazoles, alkylation, trichloroacetimidates, azaindazoles

ID: J66-Y2022