Yallamalla Srinivas

New diterpenoids from Caesalpinia species and their cytotoxic activity.

Chemical investigation on Caesalpinia crista afforded two new diterpenoids, 6beta-cinnamoyloxy-7beta-acetoxyvouacapen-5alpha-ol and 6beta,7beta-dibenzoyloxyvouacapen-5alpha-ol and on Caesalpiniapulcherrima another new diterpenoid, 12-demethyl neocaesalpin F along with several known constituents. The structures of the new compounds were settled from their 1D and 2D NMR spectral data. The cytotoxicity of these compounds was measured on two different cancer cell lines.

EFFICIENT SYNTHESIS OF 5-SUBSTITUTED 2,3-DIPHENYL AND 5-SUBSTITUTED 1-ARYL-2,3-DIPHENYL IMIDAZOLES USING POLYETHYLENE GLYCOL

Treatment of benzoin with an aldehyde and NH4OAc in polyethylene glycol (PEG-400) under reflux afforded a 5-substituted 2,3-diphenyl imidazole while the same reaction along with an additional aniline produced 5-substituted 1-aryl 2,3-diphenyl imidazole. No any catalyst or solvent was required to carry out this conversion, and the imidazoles were formed in excellent yields.

Efficient Bromination of Alkenes and Alkynes Using Potassium Bromide and Diacetoxy Iodobenzene

Abstract Bromination of alkenes and alkynes has efficiently been carried out at room temperature in short reaction times using KBr and diacetoxy iodobenzene in CH2Cl2-H2O (1:1) to prepare the corresponding trans-dibromo compounds in excellent yields.

Bromination of alkenes and alkynes with (bromodimethyl)sulfonium bromide

Alkenes and alkynes were brominated efficiently in high yields with (bromodimethyl)sulfonium bromide in acetonitrile at room temperature. Alkenes produced the corresponding trans-dibromo compounds while alkynes (except phenylacetylene) afforded both the trans-dibromo products (major) and the tetrabromo derivatives (minor). However, phenylacetylene furnished solely the tetrabromo compound.

PMA/SiO2: An Efficient and Reusable Heterogeneous Catalyst for the Synthesis of β-Acetamidocarbonyl Compounds by Multicomponent Reaction

Abstract Phosphomolybdic acid supported on silica (PMA/SiO2) has been used as an efficient heterogeneous catalyst for the preparation of β-acetamidoketones and esters in good yields. The reaction conditions are mild, and the catalyst can be recycled.

Zirconium tetrachloride catalysed synthesis of symmetric and unsymmetric ethers from secondary benzylic alcohols

Secondary benzylic alcohols are coupled in the presence of zirconium tetrachloride to afford the corresponding symmetrical ethers in good yields. Unsymmetric ethers are obtained with good selectivity by condensation of two different secondary benzylic alcohols under the action of the same catalyst.