A highly efficient, green, rapid, and chemoselective oxidation of sulfides using hydrogen peroxide and boric acid as the catalyst under solvent-free conditions

Synthesis of dipyrromethanes in aqueous media using boric acid

“…[23][24][25] Boric acid has been used as catalyst for synthesis of bis(indolyl)methanes, 26 benzoxanthenes, 27 dehydration of glucose, 28 protection and deprotection of alcohols and ethers, 29 Nacylation, 30 bromination, 31 aza Michael reactions, 32 Biginelli reactions 33 and other condensation reactions. [34][35][36] Herein, we have described the use of boric acid as an innocuous and highly efficient catalyst for the condensation reaction of pyrrole and aldehydes in aqueous medium to afford the corresponding dipyrromethanes. This investigation presents the simplest protocol for this type of reactions and anticipates as interesting for wide range of organic chemists.…”

Boric acid-catalyzed multi-component reaction for efficient synthesis of 4H-isoxazol-5-ones in aqueous medium

“…Recently, the organic synthesis of boric acid has attracted great interest because it is commercially available, environmentally benign, inexpensive, and easy to handle. Recently, this reagent has been used in various reactions including aza-Michael reaction [20], transesterification of ethyl acetoacetate [21], oxidation of sulfides [22], Biginelli reaction [23], and Mannich reaction [24]. In addition, it has also been used for the preparation of compounds such as the synthesis of 1,5-benzodiazepine derivatives [25], 2-amino-3,5-dicarbonitrile-6-thio-pyridines [26], 1-amidoalkyl-2-naphthols [27], dibenzoxanthenes [28], a-aminophosphonates [29], b-acetamido ketones [30], and a-hydroxyamides [31].…”

Keggin heteropolycompounds as catalysts for liquid-phase oxidation of sulfides to sulfoxides/sulfones by hydrogen peroxide

“…High conversion (100%) within a very short time was observed using molybdovanadophosphate heteropolycompounds, H 4 We have found a clean and convenient procedure for oxidizing sulfides to sulfoxides/sulfones, with 35% aqueous H 2 O 2 (2 or 20 mmol, respectively) and a catalytic amount of pyridinium salt from heteropolyacids. Reagents and catalysts are cheap and easily available.…”

“…The most widely used method for the preparation of sulfoxides and sulfones is the oxidation of the corresponding sulfide. For this reason, sulfide oxidation to sulfoxides and sulfones has been the subject of many studies, and several methods for this transformation have been reported in the literature [3][4][5][6][7][8]. Some traditional oxidizing reagents used for this purpose include nitric acid, trifluoroperacetic acid, hydrogen peroxide, nitromethane solution in dilute NO 3 H/H 2 SO 4 , iodic acid, other hypervalent iodine reagents, and CAN (cerium ammonium nitrate), among others [1,[8][9][10][11].…”