A Single‐Pot Template Reaction Towards a Manganese‐Based T (1) Contrast Agent

Manganese‐based contrast agents (MnCAs) have emerged as suitable alternatives to gadolinium‐based contrast agents (GdCAs). However, due to their kinetic lability and laborious synthetic procedures, only a few MnCAs have found clinical MRI application. In this work, we have employed a highly innovative single‐pot template synthetic strategy to develop a MnCA, MnL(Me), and studied the most important physicochemical properties in vitro. MnL(Me) displays optimized r (1) relaxivities at both medium (20 and 64 MHz) and high magnetic fields (300 and 400 MHz) and an enhanced r (1) (b)=21.1 mM(−1) s(−1) (20 MHz, 298 K, pH 7.4) upon binding to BSA (K (a)=4.2×10(3) M(−1)). In vivo studies show that MnL(Me) is cleared intact into the bladder through renal excretion and has a prolonged blood half‐life compared to the commercial GdCA Magnevist. MnL(Me) shows great promise as a novel MRI contrast agent.