Parmentier, Michael, Hoehn, Pascale, Lanz, Marian and Gallou, Fabrice (2020) Synthesis of 5-iodo-7-aza-indazole by Diels–Alder cascade and se-lected examples of C–C and C–N cross-coupling reactions. Organic process research & development.

Abstract

Although pyrimidines are not among the most reactive partners in intramolecular inverse-electron demand [4s+2s] reactions with alkynes, they could be activat-ed under mild and practical conditions, leading to fused nitrogen-containing heterocycles. We report an opti-mized synthesis of a 5-iodo-7-aza-indazole by a one-pot Diels–Alder cascade that starts from a pyrimidine sub-stituted in the 2-position by an (alkynyl)hydrazone. The safety of the process and the environmental impact were thoroughly evaluated. Eventually, a selection of cross-coupling reactions of 17 was studied and allowed the introduction of carbon- and nitrogen-based nucleophiles at the C5-position in good to excellent yields.

Item Type:	Article
Date Deposited:	16 May 2020 00:45
Last Modified:	16 May 2020 00:45
URI:	https://oak.novartis.com/id/eprint/42564