Ultrasound-assisted catalyst free synthesis of 1,4-/1,5-disubstituted-1,2,3-triazoles in aqueous medium

Ultrasound-assisted transition-metal-free catalysis: a sustainable route towards the synthesis of bioactive heterocycles

“…Recently, Karthikeyan et al 95 demonstrated a convenient and straightforward strategy to access a vast array of 1,5-substituted triazoles 87 and 1,4-substituted triazoles 89 ( Scheme 22 ). By employing metal- and catalyst-free conditions, the ultrasound-assisted treatment of various azides 85 and nitroolefins 86 or β-enaminones 88 with water as the green solvent at room temperature efficiently produced the respective products 87 and 89 in 72–92% and 72–90% yield respectively at 30 minutes.…”

Recent Progress in Catalytic Synthesis of 1,2,3-Triazoles

“…The reaction consists of metal-free annulation reactions of alkyl propiolates 152 with tosyl hydrazine 135 to give 1,5-disubstituted 1,2,3-triazoles 154 in according to Scheme 49. More recently, Kiranmye and co-workers [106] published the synthesis of 1,5-disubstitu ted 1,2,3-triazoles 160 in aqueous medium under ultrasound-assisted catalyst-free reaction conditions. The synthetic route is straightforward, convenient, and consists of preparation of 1,5-disubstituted 1,2,3-triazoles 160 via eliminative 1,3-dipolar cycloaddition of azides 158 with nitroolefins 159 (Scheme 51).…”

Ultrasound Probe‐assisted Telescopic One‐pot Synthesis of Spiro[indene‐2,2’‐naphthalene]‐4’‐carbonitrile Derivatives using Fe3O4@SCH2CO2H@Ni‐NH2as a Reusable Nanocatalyst

“…[9,10] Compared to thermal methods, milder reaction condition, great yields in short times, and decrease of side products have been reported with the help of ultrasonic technique. [11] Nanoporous materials have received a lot of attention owing to their fascinating features, involving large pore volume, high special surface area, and acceptable thermal stability. Nevertheless, the isolation and retrieval of them are not convenient so that magnetic nanoparticles (MNPs) can be employed in their structure to overcome those obstacles.…”

“…Ultrasound waves generate not only extreme heating but also high pressure by imploding of bubbles which can accelerate an organic transformation at the synthesis pathway [9,10] . Compared to thermal methods, milder reaction condition, great yields in short times, and decrease of side products have been reported with the help of ultrasonic technique [11] …”