Time-Reduced N-Methylation: Exploring a Faster Synthesis Technique

Backbone N-methylation is a pivotal peptide modification that enhances lipophilicity, metabolic stability, and binding affinity or specificity, thereby improving bioactive peptides' bioavailability. Substitution of a backbone amide hydrogen with a methyl group is a three-step procedure which is fully integrated with solid-phase peptide synthesis strategy and usually takes about 4 h. We have revolutionized this process by optimizing the method and slashing the total N-methylation procedure time from 4 h to just 40 min. Moreover, we demonstrate that N-methylation can be equally efficient regardless of the laboratory equipment used, such as a standard laboratory shaker, microwave synthesizer, or common ultrasonic bath. Our study not only results in acceleration of the N-methylation process during solid-phase peptide synthesis but also offers a flexible choice of laboratory equipment, making peptide modifications more efficient and achievable.