Synthesis of 1H-1,2,3-triazoles—Rufinamide analogs by 1,3-dipolar cycloaddition and eletrocyclization reactions of trifluoroacetyl enolethers under thermal solventless conditions

Furan Dearomatization: A Route to Diverse Fluoroalkyl/Aryl Triazoles

The 5-fluoroalkyl-1,2,3-triazoles, serving as a pivotal element in medicinal chemistry, hold substantial research significance. In this work, we developed a furan dearomatization reaction for the synthesis of various 5-fluoroalkyl-1,2,3-triazoles, which contains -CF3, -CF2H, -CF2CF3, -CF2CF2CF3, -CF2CO2Et, and -C6F5. This methodology relies on the intermolecular [3 + 2] cycloaddition/furan ring-opening triggered by α-fluoroalkyl furfuryl cation with azides to stereoselectively synthesize a series of (E)-fluoroalkyl enone triazoles. The reaction proceeds without metal participation, exhibits excellent substrate tolerance, and has excellent synthetic utility.

Synthesis of 5-trifluoromethyl-1,2,3-triazoles via base-mediated cascade annulation of diazo compounds with trifluoroacetimidoyl chlorides

A metal-, azide- and CF₃-reagent free approach for the synthesis of 5-trifluoromethyl-1,2,3-triazoles via base-mediated cascade annulation of diazo compounds with trifluoroacetimidoyl chlorides has been developed.

Catalytic Enantioselective Addition of an Allyl Group to Ketones Containing a Tri-, a Di-, or a Monohalomethyl Moiety. Stereochemical Control Based on Distinctive Electronic and Steric Attributes of C-Cl, C-Br, and C-F Bonds

We disclose the results of an investigation designed to generate insight regarding the differences in the electronic and steric attributes of C-F, C-Cl, and C-Br bonds. Mechanistic insight has been gleaned by analysis of variations in enantioselectivity, regarding the ability of electrostatic contact between a halomethyl moiety and a catalyst's ammonium group as opposed to factors lowering steric repulsion and/or dipole minimization. In the process, catalytic and enantioselective methods have been developed for transforming a wide range of trihalomethyl (halogen = Cl or Br), dihalomethyl, or monohalomethyl (halogen = F, Cl, or Br) ketones to the corresponding tertiary homoallylic alcohols. By exploiting electrostatic attraction between a halomethyl moiety and the catalyst's ammonium moiety and steric factors, high enantioselectivity was attained in many instances. Reactions can be performed with 0.5-5.0 mol % of an in situ generated boryl-ammonium catalyst, affording products in 42-99% yield and up to >99:1 enantiomeric ratio. Not only are there no existing protocols for accessing the great majority of the resulting products enantioselectively but also in some cases there are hardly any instances of a catalytic enantioselective addition of a carbon-based nucleophile (e.g., one enzyme-catalyzed aldol addition involving trichloromethyl ketones, and none with dichloromethyl, tribromomethyl, or dibromomethyl ketones). The approach is scalable and offers an expeditious route to the enantioselective synthesis of versatile and otherwise difficult to access aldehydes that bear an α-halo-substituted quaternary carbon stereogenic center as well as an assortment of 2,2-disubstituted epoxides that contain an easily modifiable alkene. Tertiary homoallylic alcohols containing a triazole and a halomethyl moiety, structural units relevant to drug development, may also be accessed efficiently with exceptional enantioselectivity.

Novel triazoles of 3-acetylbetulin and betulone as anticancer agents

The CuAAC reaction of azides and acetylenic triterpenes was used for synthesis of new triazoles of 3-acetylbetulin and betulone. The triazole derivatives were evaluated for their anticancer activity in vitro against amelanotic melanoma C-32, ductal carcinoma T47D and glioblastoma SNB-19 cell lines. 28-[1-(3’-Deoxythymidine-5’-yl)-1H-1,2,3-triazol-4-yl]carbonylbetulone 6e exhibited a significant IC₅₀ value (0.17 µM) against the human glioblastoma SNB-19 cell line, an almost 5-fold higher potency while compared with reference cisplatin.

Discovery of a novel 6,7-disubstituted-4-(2-fluorophenoxy)quinolines bearing 1,2,3-triazole-4-carboxamide moiety as potent c-Met kinase inhibitors

A series of 6,7-disubstituted-4-(2-fluorophenoxy)quinoline derivatives possessing 1,2,3-triazole-4-carboxamide moiety were designed, synthesized and evaluated for their in vitro cytotoxic activities against four typical cancer cell lines (A549, H460, HT-29, and MKN-45). Most compounds showed moderate-to-excellent antiproliferative activity. Compounds 32, 36, 37, 45, 51, and 52 were further examined for their inhibitory activity against c-Met kinase. The promising compound 37, with a c-Met IC50 value of 2.27 nM, was identified as a multitargeted receptor tyrosine kinase inhibitor. The analysis of their structure-activity relationships indicated that compounds with EWGs, especially chloro group, at 2-position on the phenyl ring (moiety B) have potent antitumor activity.

Promotion of 1,3-dipolar cycloaddition between azides and β-enaminones by deep eutectic solvents

The metal-free, high selectivity and efficient synthesis of 4-acyl triazoles in a DES (ChCl:ethylene glycol) is reported.