Utilização de Oxone® e ultrassom na síntese de 4-calcogenil- 1H-isocromen-1-onas e 4-calcogenilisoquinolínio(tosil)amidas

Abstract

In the present work, a method for the synthesis of 4-chalcogenyl-1Hisochromen- 1-ones from the reaction between alkyl 2-(organylethynyl)benzoates and electrophilic chalcogen species was described. These species were generated in situ by the reaction between diorganyl dichalcogenides and Oxone®, using ethanol or glycerol as solvent and ultrasound irradiation. Using the developed method, it was possible to synthesize twenty-five products satisfactorily (74-95%) in short reaction times (30-70 min). Furthermore, 4- chalcogenyl-1H-isochromen-1-ones were applied as substrates in the thionation reaction, employing Lawesson's reagent and microwave irradiation in a solventfree medium, obtaining the thio-derivatives compounds in yields of up to 99% in 15 min of reaction time. Additionally, a one-pot two-step method for the synthesis of 4- (chalcogenyl)isoquinolinium(tosyl)amides using Oxone® and ultrasound was developed. Firstly, N’-(2-alkynylbenzylidene) hydrazides were synthesized under ultrasound irradiation, for subsequent addition of diorganyl dichalcogenides and Oxone® to the reaction medium. This method proved to be efficient for a wide range of diorganyl dichalcogenides and N’-(2-alkynylbenzylidene)hydrazides, allowing the synthesis of twenty-eight 4-chalcogenylisoquinolinium(tosyl)amides with good to excellent yields (70-95%) and in short reaction times (50-140 min).