A new and versatile class of cyclic diazodicarboxamides that reacts efficiently and selectively with phenols and the phenolic side chain of tyrosine through an ene-like reaction is reported. This mild aqueous tyrosine ligation reaction works over a broad pH range and expands the repertoire of aqueous chemistries available for small molecule, peptide, and protein modification. The tyrosine ligat...

A simple, highly efficient and green procedure for the condensation of o-phenylenediamines with 1, 2-dicarbonyl compounds in the presence of vitamin C, as an inexpensive organocatalyst, is described. Using this method, variety of quinoxaline derivatives with different electron releasing and electron withdrawing substituents, are produced in high to excellent yields at room temperature in ethano...

A green and efficient protocol for the synthesis of 3,3,6,6-tetramethyl-9-aryl-1,8-dioxooctahydroxanthene derivatives via cyclocondensation of 5,5-dimethyl-1,3-cyclohexanedione and aromatic aldehydes in the presence of catalytic amount of 10-molybdo-2-vanadophosphoric acid under solvent-free conditions has been described. The 10-molybdo-2-vanadophosphoric acid was prepared and characterized by ...

A green and efficient protocol for the synthesis of 3,3,6,6-tetramethyl-9-aryl-1,8-dioxooctahydroxanthene derivatives via cyclocondensation of 5,5-dimethyl-1,3-cyclohexanedione and aromatic aldehydes in the presence of catalytic amount of 10-molybdo-2-vanadophosphoric acid under solvent-free conditions has been described. The 10-molybdo-2-vanadophosphoric acid was prepared and characterized by ...

Nanomagnetite-Fe3O4 is used as a highly efficient, mild, green and recyclable nanomagnetite catalyst for the synthesis of 4,4´-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol) derivatives in solvent-free conditions. The condensation reaction of 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one with aromatic aldehydes affords the title compounds in high yields and short reaction times. The nanocataly...