Investigating Scale-Up and Further Applications of DABAL-Me3 Promoted Amide Synthesis

Methods for the batch scale up of DABAL-Me3 promoted direct ester to amide synthesis have been demonstrated at 10–100 g scales using a tert-amide model compound. Procedures for 20 g scale couplings in standard laboratory glassware and up to 0.1 kg in industry-standard jacketed glass reactors in near quantitative yields are given. A derivative of the anticancer agent Imatinib (Gleevec) has been synthesized on a 26 g scale (98% yield, >98% purity) establishing DABAL-Me3 as a potential alternative for the synthesis of amides in API scale preparations. Continuous flow methodology provides a method for larger scales (productivities of >50 g h–1). In addition, nitriles were coupled to primary amines and hydrazines with DABAL-Me3, resulting in the clean formation of free amidines (16 examples) and amidrazones.