Synthesis of guanidines via the I2 mediated desulfurization of N,N′-di-Boc-thiourea

Synthetic and natural guanidine derivatives as antitumor and antimicrobial agents: A review

Guanidines are fascinating small nitrogen-rich organic compounds, which have been frequently associated with a wide range of biological activities. This is mainly due to their interesting chemical features. For these reasons, for the past decades, researchers have been synthesizing and evaluating guanidine derivatives. In fact, there are currently on the market several guanidine-bearing drugs. Given the broad panoply of pharmacological activities displayed by guanidine compounds, in this review, we chose to focus on antitumor, antibacterial, antiviral, antifungal, and antiprotozoal activities presented by several natural and synthetic guanidine derivatives, which are undergoing preclinical and clinical studies from January 2010 to January 2023. Moreover, we also present guanidine-containing drugs currently in the market for the treatment of cancer and several infectious diseases. In the preclinical and clinical setting, most of the synthesized and natural guanidine derivatives are being evaluated as antitumor and antibacterial agents. Even though DNA is the most known target of this type of compounds, their cytotoxicity also involves several other different mechanisms, such as interference with bacterial cell membranes, reactive oxygen species (ROS) formation, mitochondrial-mediated apoptosis, mediated-Rac1 inhibition, among others. As for the compounds already used as pharmacological drugs, their main application is in the treatment of different types of cancer, such as breast, lung, prostate, and leukemia. Guanidine-containing drugs are also being used for the treatment of bacterial, antiprotozoal, antiviral infections and, recently, have been proposed for the treatment of COVID-19. To conclude, the guanidine group is a privileged scaffold in drug design. Its remarkable cytotoxic activities, especially in the field of oncology, still make it suitable for a deeper investigation to afford more efficient and target-specific drugs.

7-Guanidinyl Coumarins: Synthesis, Photophysical Properties, and Application to Exploit the Pd-Catalyzed Release of Guanidines

Molecular manipulation of guanidino-containing biomolecules in a cellular environment is fundamental to exploiting protein function and drug release, but currently, there is a lack of suitable methods for reaction screening and monitoring. To exploit the potential of the fluorescent method in this respect, herein, we evaluated a novel array of 7-guanidinyl coumarins by incorporating different substituted guanidino moieties into a coumarin scaffold. These compounds were prepared by guanidinylation reagent S-methylisothiourea or TFA-protected pyrazole-carboxamidine. Examination of their photophysical properties revealed that the fluorescence emission of alkyloxycarbonyl-substituted guanidinyl coumarin was significantly enhanced as compared with the unsubstituted analogue. This dramatic fluorescence difference enabled preliminary exploitation of the Pd-catalyzed release of allyloxycarbonyl (Alloc)-caged guanidinyl coumarin-6 in living cells.

Synthesis of Nitriles via the Iodine-Mediated Dehydrosulfurization of Thioamides

A simple general method for the synthesis of nitriles using the inexpensive and easy to handle iodine (I₂) is described herein. The reaction of thioamides with I₂ in the presence of triethylamine at room temperature under aerobic conditions afforded various nitriles bearing aryl, vinyl, and alkyl groups in good-to-excellent yields. This method was also effective for conversion from thioureas to cyanamides.

The chemistry and biology of guanidine secondary metabolites

Covering: 2017-2019Guanidine natural products isolated from microorganisms, marine invertebrates and terrestrial plants, amphibians and spiders, represented by non-ribosomal peptides, guanidine-bearing polyketides, alkaloids, terpenoids and shikimic acid derived, are the subject of this review. The topics include the discovery of new metabolites, total synthesis of natural guanidine compounds, biological activity and mechanism-of-action, biosynthesis and ecological functions.

Iodine-Promoted Synthesis of 4-Aryl-2-(arylsulfonyl)quinolones by Desulfurative C–S Cross-Coupling Reaction of Quinoline-2-thiones with Sodium Sulfinates

An iodine-induced sulfonylation of quinoline-2-thiones with sodium arenesulfinates as sulfur sources for the synthesis of 4-aryl-2-(arylsulfonyl)quinoline derivatives is described. The 4-aryl-2-(arylsulfonyl)quinoline derivatives can be obtained in a moderate to good yields. This C–S bond cleavage and C–S cross-coupling proceeds in the absence of a metal under inexpensive and nontoxic conditions and it displays a broad substrate scope.

Iodine-catalyzed guanylation of amines withN,N′-di-Boc-thiourea

Iodine-catalyzed guanylation of amines withN,N′-di-Boc-thiourea is especially useful for both electronically and sterically deactivated primary anilines.