B(HSO4)3: a novel and efficient solid acid catalyst for the regioselective conversion of epoxides to thiocyanohydrins under solvent-free conditions

Abstract

B(HSO 4 ) 3 foi facilmente preparado e usado como um novo e eficiente catalisador ácido sólido, para conversão de epóxidos às correspondentes tiocianohidrinas sob condições livre de solvente, com altos rendimentos. As principais características desta metodologia são o baixo custo do processo, a facilidade de obtenção do catalisador, a versatilidade e alta regiosseletividade do procedimento.B(HSO 4 ) 3 was easily prepared and used as a novel and efficient solid acid catalyst for conversion of epoxides to the corresponding thiocyanohydrins under solvent-free conditions with high isolated yields. The salient features of this methodology are cheaper process, easy availability of the catalyst, versatility, and high regioselectivity of the procedure.

Silica supported boric tri-sulfuric anhydride as a novel and efficient catalyst for solvent-free synthesis of coumarins via Pechmann condensation

“…This catalyst was prepared by supporting boric tri-sulfuric anhydride (8 meq., 0.87 g, purity = 92.5%) on the surface of silicagel (0.13 g). Boric trisulfuric anhydride (B(OSO 3 H) 3 , MW = 302.02 g/mol) was prepared according to reported procedure 26 by gradual addition of chlorosulfonic acid to anhydrous boric acid. In order to calculate the acidic strength of the catalyst we performed the pH-metric titration of the catalyst using aqueous NaOH solutions with three different concentrations.…”

Boron sulfonic acid (BSA) catalyzed selective synthesis of aryl-bis(2-hydroxynaphth-1-yl)methanes and 14-alkyl- and 14-aryl-14H-dibenzoxanthenes under solvent-free condition

“…The boron sulfonic acid (BSA) catalyst was prepared via the reaction of boric acid with chlorosulfonic acid by following the procedure reported by Kiasat et al in 2008. 3 A 50 mL suction flask fitted with a constant pressure dropping funnel was connected to a vacuum system through water and an alkali trap. To the flak, 12 mmol of boric acid was introduced and after that, 36 mmol of chlorosulfonic acid was added drop wise over a period of an hour at ambient temperature with the help of pressure dropping funnel.…”

“…2 Boron sulfonic acid (BSA) is a versatile solid acid which was first introduced by Kiasat et al that makes reaction processes convenient, more economic, and environmentally benign (Scheme 1). 3 Owing to the numerous advantages associated with this cheap and non-hazardous reagent, BSA has been explored as a powerful catalyst for various organic transformations under mild conditions. 4 In continuation of our research work on solid acid catalysed organic transformations, [5][6] we have the opportunity to explore the catalytic activity of BSA for the selective generation of 14-alkyl or aryl 14H-dibenzoxanthenes and its precursors aryl or alkyl-bis(2-hydroxy-1-naphthyl)methane from the acid catalysed reaction of 2-naphthol with aldehydes (Scheme 2).…”

2,6-Pyridinedicarboxylic acid as an efficient and mild organocatalyst for the one-pot synthesis of xanthene derivative

“…For example, high efficiency and selectivity, operational simplicity, environmental compatibility, nontoxic, reusability, low cost, ease of isolation and benefit for industry as well as environment [27][28][29][30].…”