Meldrum's Acid Furfural Conjugate MAFC: A New Entry as Chromogenic Sensor for Specific Amine Identification

Bioactive amines are highly relevant for clinical and industrial application to ensure the metabolic status of a biological process. Apart from this, generally, amine identification is a key step in various bioorganic processes ranging from protein chemistry to biomaterial fabrication. However, many amines have a negative impact on the environment and the excess intake of amines can have tremendous adverse health effects. Thus, easy, fast, sensitive, and reliable sensing methods for amine identification are strongly searched for. In the past few years, Meldrum's acid furfural conjugate (MAFC) has been extensively explored as a starting material for the synthesis of photoswitchable donor-acceptor Stenhouse adducts (DASA). DASA formation hereby results from the rapid reaction of MAFC with primary and secondary amines, which has so far been demonstrated through numerous publications for different applications. The linear form of the MAFC-based DASA exhibits intense pink coloration due to its linear conjugated triene-2-ol conformation, which has inspired researchers to use this easy synthesizable molecule as an optical sensor for primary, secondary, and biogenic amines. Due to its new entry into amine identification, a collection of the literature exclusively on MAFC is demanded. In this mini review, we intend to present the state-of-the-art of MAFC as an optical molecular sensor in hopes to motivate researchers to find even more applications of MAFC-based sensors and methods that pave the way to their usage in medicinal applications.