Synthesis of Substituted (±)-3,4-Dihydrocoumarins Using H-Y Zeolite

Single-step synthesis of 4-phenyl and 3,4-dihydro-4-phenyl coumarins using a recyclable Preyssler heteropolyacid catalyst under solvent-free reaction conditions

“…In order to quantify how much 'greener' the methodology is, the atom economy, atomic efficiency factor, process mass intensity, and EcoScale were calculated for each reaction product and the results are also presented in Table 5. The resulting parameters were also compared with classic methods for the synthesis of coumarins and dihydrocoumarins [17,30]. The results (listed in Table 6) indicate an improvement in the synthesis of coumarins from a green chemistry viewpoint, with better yield, atom economy, environmental factor, process mass intensity and EcoScale factors.…”

“…The methods for the synthesis of 4-phenyl-3,4-dihydrocoumarins include the catalytic hydrogenation of coumarins [24][25][26], the Pondorff reaction for the condensation of phenols with a, b-unsaturated acids in the presence of an acid catalyst (for example, H 2 SO 4 [17], P 2 O 5 /H 3 PO 4 H 3 [27], TFA [28], BF 3 [29], zeolites [30], and montmorillonite K-10 using microwave irradiation [22]), arylacrylate lactonization [20,[31][32][33], Houben-Hoesch condensation of phenols with a,b-unsaturated nitriles in the presence of ZnCl 2 [17] or AlCl 3 /HCl [34], consecutive Friedel-Crafts alkylation-acylation [35], and via Fischer carbenes [36].…”

Catalytic activity of Keggin heteropolycompounds in the Pechmann reaction

“…Identified in the 1820s, coumarin has been synthesized in the laboratory since 1868 and used to make perfumes and flavours [3]. There are many synthetic routes to obtain coumarins, such as Pechmann [4], Perkins [5], Knoevenagel [6,7], Reformasky [8] and Wittig [9][10][11][12] reactions.…”