Scale-up of the green synthesis of azacycloalkanes and isoindolines under microwave irradiation

A green approach to N-heterocyclization reactions ranging in scale from 20 mmol to 1 mol performed under microwave irradiation in open vessels has been investigated. By using water as the solvent and no transition metal catalysts, N-heterocycles are formed in a fraction of the time needed for conventional synthesis of these compounds. The obtained yields indicate that reactions can be performed at atmospheric pressure using the same reaction conditions as the corresponding sealed-vessel reactions. Single-mode and multimode microwave cavities have been used for open-vessel synthesis without changing reaction times producing similar yields.