Improvement of selectivity in the Fries rearrangement and direct acylation reactions by means of P2O5/SiO2 under microwave irradiation in solvent-free media

P2O5/SiO2 as a New, Efficient and Reusable Catalyst for Preparation of 4,4′‐Epoxydicoumarins Under Solvent‐free Conditions

“…Phosphorus pentoxide/silica gel (P 2 O 5 /SiO 2 ) is inexpensive, green, commercially available and heterogeneous catalytic system which has been used in several organic transformations, such as synthesis of N-sulfonyl imines 4 , condensation of indoles with carbonyl compounds 5 , esterification 6 , oxidation of sulfides to sulfoxides 7 , schmidt reaction 8 , Fries rearrangement 9 , direct sulfonylation of aromatic rings 10 , oxime preparation 11 , conversion of aldehydes to acylals 12 , selective deprotection of 1,1-diacetals 13 and acetalization of carbonyl compounds 14 .…”

P2O5/SiO2 as an Efficient, Green and Heterogeneous Catalytic System for the Solvent‐Free Synthesis of 3,4‐Dihydropyrimidin‐2‐(1H)‐ones (and ‐Thiones)

“…Phosphorus pentoxide/silica gel is an inexpensive, green, commercially available and heterogeneous catalytic system which has been used in several organic transformations, such as synthesis of N-sulfonyl imines 25 , condensation of indoles with carbonyl compounds 26 , esterification 27 , oxidation of sulfides to sulfoxides 28 , Schmidt reaction 29 , Fries rearrangement 30 , direct sulfonylation of aromatic rings 31 , oxime preparation 32 , conversion of aldehydes to acylals 33 , selective deprotection of 1,1-diacetals 34 , and acetalization of carbonyl compounds 35 .…”

ChemInform Abstract: Silica Gel Supported Phosphorus Pentoxide: A Simple and Efficient Solid‐Supported Reagent for Esterification of Long‐Chain Carboxylic Acids and Their Antimicrobial Screening.

“…30 In view of the above mentioned pharmacological and industrial uses of fatty esters and our ongoing efforts to synthesize fatty acid derivatives, 31 we have found that P 2 O 5 /SiO 2 can be used for the esterification of fatty acids with aromatic alcohols under solvent-free conditions. According to the literature P 2 O 5 /silica gel has been used in acylation, 32,33 Fries rearrangement, 34 protection and deprotection of aldehydes or alcohols, 35 nitration, 36 oxidation, 37 and Beckmann or Schmidt rearrangements. 38 To the best of our knowledge, it is the first example of esterification of fatty acids with various aromatic alcohols by solid-phase approach.…”