Microwave-assisted flexible synthesis of 7-azaindoles.

7-Azaindoles are versatile building blocks, especially in medicinal chemistry, where they serve as bioisosteres of indoles or purines. Herein, we are presenting a robust and flexible synthesis of 1,3- and 1,3,6-substituted 7-azaindoles starting from nicotinic acid derivatives or 2,6-dichloropyridine, respectively. Microwave heating dramatically accelerates the penultimate reaction step, an epoxide-opening-cyclization-dehydration sequence. The functional group compatibility of the reaction is examined as well as the application of the products in further functionalizations.