Guanylated Diamines, Triamines, and Polyamines: Chemistry and biological properties

Daniele Castagnolo, Silvia Schenone, Maurizio Botta

Research output: Contribution to journalArticlepeer-review

105 Citations (Scopus)


Naturally occurring polyamines (PAs) play a pivotal role in the life of all organisms from bacteria to man. The human PAs putrescine, spermidine, and spermine are fundamental for cell viability, having a multitude of in vivo functions, and their study is an expanding field of research. The polycationic nature of these polyamines is important for their biological activities and for their in vivo interaction with macromolecules such as enzymes or the polyanionic nucleic acids. Several reviews have been reported so far on the chemistry, synthesis, and biological properties of polyamines. However, a particular class of polyamines, namely, the guanylated polyamines, attracted the attention of many chemists and biologists in the last decades. A guanylated polyamine is a polyamine with one or more of its amino moieties as part of a guanidine function. These compounds can be sometimes referred to as polyaminoalkylguanidines. Replacement of an amino group in a biologically active polyamine compound by the strongly basic guanidinium results often in a significant increase of its potency and/or selectivity. In fact, the guanidine group is a common structural key element in a variety of natural and synthetic compounds, which show interesting biological properties or chemical behavior and have therefore found important applications in medicinal, bioorganic, supramolecular chemistry, and, most recently, asymmetric synthesis. A guanidinium group is commonly used by proteins and enzymes to recognize and bind anions through ion pairing and hydrogen bonding. The specific patterns of hydrogen bonding recognition together with the high basicity (pKa ≈ 13.5) makes the guanidium group able to play several key roles in recognition, electrophilic catalysis, and biological activity in many enzymes. As a consequence, guanylated polyamines may possess biochemical and biophysical properties amplified with respect to their parent polyamines. Moreover, being strictly related to natural bioamines and amino acids, the guanylated polyamines often have high solubility in water and bioavailability, which makes them excellent drugs or lead compounds. Guanylated polyamines (in particular guanylated diamines and triamines) play important roles in biological processes and might be produced directly by plants, animals, and humans. However, despite their simple chemical structures, these compounds showed difficulties from a synthetic point of view, mostly due to the nature of guanidine moiety, which makes these compounds highly polar and hard to handle and to purify. In addition, the presence of two or more nitrogens or guanidine moieties represents an additional issue: for instance, the regioselctive guanylation of polyamines still represents a big challenge for chemists. Different synthetic methodologies have been reported to overcome these issues such as the shrewd use of a protecting group strategy or the use of solid-phase synthesis. Moreover, possessing these compounds different reactive moieties, side reactions sometimes constitute a problem. This review will cover systematically the preparation methodologies and chemical properties of guanylated diamines, triamines, and, more generally, polyamines. Finally, a description of their most important biological properties will be reported.
Original languageEnglish
Pages (from-to)5247-5300
JournalChemical Reviews
Issue number9
Publication statusPublished - 2011


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