The naturally occurring alkaloid tryptanthrin is a valuable scaffold in medicinal chemistry with anti-inflammatory, antibacterial, antiparasitic, and anticancer properties. However, its conventional synthesis requires harsh conditions and harmful solvents like toluene, whereas previous microwave methods yielded only 30%. To address this, we present an efficient and eco-friendly microwave-assisted synthesis. Using isatin and isatoic anhydride as starting materials, this completely solvent-free methodology reduces reaction time to just 7 min, suppresses by-product formation, and achieves a superior yield. Additionally, we provide the complete assignment of its ¹H and ¹³C-NMR spectra. This advance offers a clean and sustainable route for pharmaceutical development.

The Gould–Jacobs reaction for the synthesis of ethyl 4-quinolone-3-carboxylate derivatives is described. Thus, the condensation of 4-subtituted anilines and EMME to give the corresponding diethyl anilinomethylene malonate was carried out via neat MW irradiation or refluxing ethanol. These intermediates underwent Eaton’s reagent-catalyzed cyclisation with good to excellent yields. For the first step, the MW reaction took only 7 min compared with the two hours required for conventional heating, yet the yields were comparable in almost all cases. A series of eight 4-quinolone derivatives was obtained with good yields under mild conditions and with short reaction times.

Tungstophosphoric acid (TPA) has been supported on mesoporous silicas prepared using urea as the pore forming agent. The amount of urea (20, 30, or 40% w/w) influences the silica specific surface area (S_BET), total pore volume (Vp), and average pore diameter (Dp). The materials synthetized using 20% w/w (SiU20) display mainly mesoporous structures, with the highest Vp and Dp values being chosen to be used as TPA support. The SiU20-TPA solids with different TPA loadings (10, 20, or 30% w/w) have been used as supports for chiral copper catalysts with bis(oxazoline) or azabis(oxazoline) ligands. The catalytic efficiency of enantioselective cyclopropanation strongly depends on support morphology and TPA loading. SiU-TPA20 has been shown to be the optimal one. The stability of the complex is also a very important parameter, and the best results are obtained with an excess of chiral ligand to ensure the correct formation of the complex on the solid. In this way, with azabox-Cu/SiU20-TPA20 it is possible to obtain a highly selective (90% ee for the trans-cyclopropanes) and recoverable catalyst.