A new preparative method and some chemical properties of 4-R-furazan-3-carboxylic acid amidrazones

FSO2N3-Enabled Synthesis of Tetrazoles from Amidines and Guanidines

Herein we report the facile syntheses of tetrazoles enabled by FSO2N3 under mild conditions. FSO2N3 has been shown as the most powerful diazotizing reagent, which converts thousands of primary amines to azides fast and orthogonally. As the follow-up studies of the diazo transfer reaction using FSO2N3, we discover that amidines and guanidines are rapidly transformed into tetrazole derivatives when reacting with FSO2N3 under an aqueous environment, which is unprecedented for tetrazole synthesis.

A Review of the Biological Activity of Amidrazone Derivatives

Amidrazones are widely used in chemical synthesis, industry and agriculture. We compiled some of the most important findings on the biological activities of amidrazones described in the years 2010-2022. The data were obtained using the ScienceDirect, Reaxys and Google Scholar search engines with keywords (amidrazone, carbohydrazonamide, carboximidohydrazide, aminoguanidine) and structure strategies. Compounds with significant biological activities were included in the review. The described structures derived from amidrazones include: amidrazone derivatives; aminoguanidine derivatives; complexes obtained using amidrazones as ligands; and some cyclic compounds obtained from amidrazones and/or containing an amidrazone moiety in their structures. This review includes chapters based on compound activities, including: tuberculostatic, antibacterial, antifungal, antiparasitic, antiviral, anti-inflammatory, cytoprotective, and antitumor compounds, as well as furin and acetylocholinesterase inhibitors. Detailed information on the compounds tested in vivo, along the mechanisms of action and toxicity of the selected amidrazone derivatives, are described. We describe examples of compounds that have a chance of becoming drugs due to promising preclinical or clinical research, as well as old drugs with new therapeutic targets (repositioning) which have the potential to be used in the treatment of other diseases. The described examples prove that amidrazone derivatives are a potential source of new therapeutic substances and deserve further research.

Selective Synthesis of Bis(3-(3-(trifluoromethyl)-1H-1,2,4-triazol-5-yl)-4,4'-azo- and -azoxyfurazan Derivatives

In this paper, we report the synthesis of two new derivatives, bis(3-(3-(trifluoromethyl)-1H-1,2,4-triazol-5-yl)-4,4'-azo- and -azoxyfurazans by selective oxidation of 4-(3-(trifluoromethyl)-1H-1,2,4-triazol-5-yl)-1,2,5-oxadiazol-3-amine. Ammonium salts of these derivatives were prepared, and all of them were fully characterized by multinuclear NMR, FTIR spectroscopy, elemental analysis, differential scanning calorimetry (DSC), and single-crystal X-ray diffraction. All of the new compounds have high measured crystal densities, and the energetic properties have been investigated.

A promising cation of 4-aminofurazan-3-carboxylic acid amidrazone in desensitizing energetic materials

For the development of energetic materials, insensitive compounds have attracted considerable attention due to their improved safety and lower cost than those of sensitive energetic compounds during production, transportation, and application. In this study, insensitive 4-aminofurazan-3-carboxylic acid amidrazone was used as a cation to obtain four derivatives which were determined by X-ray single crystal diffraction. It is interesting to note that all four derivatives are insensitive to impact and friction, while the velocities of detonation for derivatives are superior to that of insensitive TATB (1,3,5-triamino-2,4,6-trinitrobenzene). Multi-factors analysis shows that the cation of 4-aminofurazan-3-carboxylic acid amidrazone is a promising furazan-based cation in desensitizing energetic compounds.

4-Aminofurazan-3-carboxylic acid amidrazone was used to obtain four derivatives confirmed by X-ray diffraction. The derivatives are insensitive to impact and friction, while the velocities of detonation are superior to that of 1,3,5-triamino-2,4,6-trinitrobenzene.

Discovery of Amino-cyclobutarene-derived Indoleamine-2,3-dioxygenase 1 (IDO1) Inhibitors for Cancer Immunotherapy

Checkpoint inhibitors have demonstrated unprecedented efficacy and are evolving to become standard of care for certain types of cancers. However, low overall response rates often hamper the broad utility and potential of these breakthrough therapies. Combination therapy strategies are currently under intensive investigation in the clinic, including the combination of PD-1/PD-L1 agents with IDO1 inhibitors. Here, we report the discovery of a class of IDO1 heme-binding inhibitors featuring a unique amino-cyclobutarene motif, which was discovered through SBDD from a known and weakly active inhibitor. Subsequent optimization efforts focused on improving metabolic stability and were greatly accelerated by utilizing a robust S_NAr reaction of a facile nitro-furazan intermediate to quickly explore different polar side chains. As a culmination of these efforts, compound 16 was identified and demonstrated a favorable overall profile with superior potency and selectivity. Extensive studies confirmed the chemical stability and drug-like properties of compound 16, rendering it a potential drug candidate.

Energetic furazan-triazole hybrid with dinitromethyl and nitramino groups: decreasing sensitivity via the formation of a planar anion

Enlarging the skeleton containing two heterocyclic five-membered rings can decrease sensitivity in comparison with most highly nitro-functionalized mono nitrogen-rich rings.

Mild Synthesis of Substituted 1,2,5-Oxadiazoles Using 1,1'-Carbonyldiimidazole as a Dehydrating Agent

1,1'-Carbonyldiimidazole was found to induce the formation of a variety of 3,4-disubstituted 1,2,5-oxadiazoles (furazans) from the corresponding bisoximes at ambient temperature. This method enables these inherently energetic compounds to be prepared at temperatures well below their decomposition points and with improved functional group compatibility relative to prior methods. Conditions were developed that allowed for the first high-yielding synthesis of chlorofurazans from their amino counterparts, enabling the mild synthetic manipulation of these heterocycles.