Synthesis and characterization of some novel coumarin based various 2-aryl-pyrido [3,2-c] coumarins

A survey of the literature reveals that the number of coumarin derivatives having heterocyclic moieties either as substituent groups or fused with parent coumarin nucleus possesses a variety of functions and are widely used in drugs and dyes. Because of this wide utility, the synthesis of coumarin has remained a subject of active interest. Looking at the importance of these heterocoumarins and with a view to exploring new methods of their synthesis, the present work was undertaken and  this synthesis deals with  various 2-aryl-pyrido [3,2-c] coumarins. The compounds have been synthesized by reacting Mannich bases of various 4-hydroxy coumarins with pyridinium salts of various aroyl methyl bromides in the presence of ammonium acetate and acetic acid. All the compounds synthesized have been characterized by analytical and spectral data. Keywords: Pyrido, Coumarins, Krohanke’s reaction

An efficient and facile synthesis of the hybrid scaffold of Pyrazole-Triazole-Chromenes nucleus using PS-TBD as a green catalyst

A series of 16 derivatives of pyrazole-triazole-chromene moieties (4a-p) were synthesized via one-pot cyclocondensation reaction of pyrazole-triazole aldehyde (1a-d), 1, 3 diketone (3a-d) and malononitrile (2a) in presence of PS-TBD as catalyst. The reusability of PS-TBD (polystyrene supported 7-methyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene) catalyst makes this reaction quick and efficient. On the basis of various trials and its results, best performance and reusability of catalyst was observed at 5 mol% concentration. The reusability of catalyst founds up to 5 runs. A synthesized compound was characterized by 1HNMR, 13CNMR, FT-IR and C, H, N elemental analysis and confirms theoretical chemical reaction. Keywords: Chromenes, Pyrazole, Triazole, PS-TBD catalysis Chemistr

Synthesis of furano[2,3-c] /pyrrolo[2,3-c]coumarins and synthesis of 1(H)-[1]benzopyrano[3,4-b][1]benzopyrano[3’,4’-d] furan-7(H)-ones /1(H)-[1]benzopyrano[3,4-b][1]benzopyrano [3’,4’-d]pyrrole-7(H)-ones

A series of synthesis of various 1-aryl-furano[2,3-c] and 1-phenyl-2-methyl-furano [2,3-c]coumarins;1-aryl-pyrrolo[2,3-c]and1-phenyl-2methylpyrrolo[2,3c]coumarins; 1aryl1H1] benzopyrano[3,4,-b][1]benzpyrano [3’,4’-d]furan-7H-ones and 1-aryl-1(H)-[1]benzopyrano[3,4,-b][1]benzpyrano[3’,4’-d]pyrrole-7(H)-ones. 1-Aryl-furano [2,3-c]coumarins and 1-phenyl-2-methyl-furano[2,3-c]coumarin have been synthesized by reacting 3-hydroxy coumarin with various 2-aryl-1-nitro-ethenes and 1-phenyl-2-nitro-propene respectively in the presence of piperidine and methanol as solvent. 1-Aryl-pyrrolo [2,3-c]coumarins and 1-phenyl-2-methyl-pyrrolo[2,3-c] coumarin also have been synthesised by reacting 3-amino coumarin with  various 2-aryl-1-nitro-ethenes and 1-phenyl-2-nitro-propene respectively in the presence of piperidine and methanol. The formation of furan and pyrrole nucleus in all above compounds follows Nef reaction mechanism. Using the Nef reaction, synthesis of various 1-aryl-1(H)-[1]benzopyrano[3,4,-b][1]benzpyrano[3’,4’-d]furan-7(H)-ones have been carried out  by reacting various 4-hydroxy coumarins with various 3-nitro-2-aryl-2H-[1]benzopyrans in the presence of piperidine and methanol. Similarly synthesis of various 1-aryl-1(H)-[1]benzopyrano[3,4,-b][1]benzpyrano [3’,4’-d]pyrrole-7(H)-ones also have been carried out by reacting various 4-hydroxy coumarins with various 3-nitro-2-aryl-2H-[1]benzopyrans in the presence of ammoniun acetate  and acetic acid. Keywords: Furan, Pyrrolo,Coumarin, Benzopyrano

Surface initiated polydopamine grafted poly([2-(methacryoyloxy)ethyl]trimethylammonium chloride) coatings to produce reverse osmosis desalination membranes with anti-biofouling properties

Commercial polyamide (PA) reverse osmosis (RO) membranes were surface modified in a sequential two-step polymerization process to impart anti-biofouling properties to the membrane surface. In the first step, a 2-bromoisobutyryl bromide initiator-polydopamine (BiBBr-initiator-PDA) layer was deposited onto the membrane surface from a Tris(hydroxymethyl)aminomethane buffered solution of dopamine hydrochloride and 2-bromoisobutyryl bromide at ambient conditions. In the second step, polymer chains of [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MTAC) were grafted-from the BiBBr-initiator-PDA surface using activators regeneration by electron transfer-atom transfer radical polymerization for between 1 and 24 h. The modified surfaces were characterized using attenuated reflectance-Fourier transform infrared spectroscopy and water contact angle and their pure water flux, saline water flux and ability to reject salt were determined. Results showed that the water flux and salt rejection properties of the PDA-g-PMTAC modified membranes were similar to the unmodified PA RO membranes. Chlorine resistance tests showed the coating had enhanced stability in regards to salt rejection properties. Significantly, after six days of incubation in nutrient solution there was 93.2% less bacteria on the PDA-g-MTAC modified PA RO membranes, compared to the unmodified membranes