http://nopr.niscair.res.in/handle/123456789/10529 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/10548 Title: Recombination of propargyl radicals to form benzene: A computational study <br/> <br/>Authors: Singh, Hari Ji; Gour, Nand Kishor <br/> <br/>Abstract: Present study involves QCISD(T)/6-311G(d,p) level calcula­tions to analyze reaction pathways during the recombination of propargyl radicals leading to the formation of benzene. A new path on the C₃H₃ recombination potential energy surface that connects 3,4-dimethylenecyclobutene (34DMCB) to benzene involving four-membered bicyclic compounds such as bicycle­[2.2.0]hexa-1(4),2-diene and bicyclo[2.2.0]hexa-2,5-diene have been determined. Geometries of all the species are optimized at HF/6-31G(d) level. All the stationary points along this path on the potential energy surface have been characterized. Single point energy calculation have been performed using QCISD(T) with 6-311G(d,p) basis set. Transition states are determined and characterized by the observation of only one imaginary frequency. Intrinsic Reaction Coordinate (IRC) calculation has also been performed in order to ascertain the existence of the transition states. <br/> <br/>Page(s): 1565-1570 http://nopr.niscair.res.in/handle/123456789/10547 Title: An excellent protocol for the synthesis of benzopyrans using basic resin under MWI <br/> <br/>Authors: Tripathi, A K; Koul, S; Taneja, Subhash C <br/> <br/>Abstract: A convenient, microwave promoted novel protocol for the synthesis of diverse kinds of substituted benzopyrans from the corresponding variety of substituted hydroxy acetophenones and keto compounds using Amberlite IRA 400 resin (basic resin) under solvent-free conditions, has been developed. This protocol is mild and more efficient than the other reported methods. <br/> <br/>Page(s): 1561-1564 http://nopr.niscair.res.in/handle/123456789/10546 Title: Solid state synthesis of ring-substituted aminobenzenesulphonic acids <br/> <br/>Authors: Kapoor, Inder Pal Singh; Kapoor, Manisha; Singh, Gurdip <br/> <br/>Abstract: &nbsp;Treatment of 2-methoxyaniline and 3,5-dichloroaniline with conc.H₂SO₄in 2:1 molar ratio at RT affords the corresponding sulphate salts. These salts have been characterized by X-ray diffraction and spectral analyses. Both these salts are found to form ring substituted aminobenzenesulphonic acids in solid state, <i style="">via</i> proton transfer, under thermal and microwave irradiations. <br/> <br/>Page(s): 1556-1560 http://nopr.niscair.res.in/handle/123456789/10545 Title: Microwave-assisted zeolite catalyzed Claisen rearrangement of allyl aryl ethers under solvent-free conditions <br/> <br/>Authors: Deodhar, Deepak K; Tipnis, Amol S; Samant, Shriniwas D <br/> <br/>Abstract: Claisen<i style=""> </i>rearrangement of allyl aryl ethers has been studied extensively over various zeolites under microwave activation and solvent free conditions at 80^oC. Hβ-zeolite is found to be an efficient catalyst for the rearrangement. The reaction gives <i style="">o</i>-rearranged product selectively instead of expected further cyclized dihydrobenzofuran derivative. <br/> <br/>Page(s): 1552-1555