Synthesis,PM3‐Semiempirical,and Biological Evaluation of Pyrazolo[4,3‐c]quinolinones

A series of α,β‐unsaturated ketones containing quinolone moieties 2 , 3 , 4 , 5 , 6 were synthesized by condensation of 7‐methoxyquinoline‐2,4(1H,3H)‐dione ( 1 ) with different aryl aldehydes. Pyrazole derivatives 8 , 9 , 10 , 11 were also synthesized via refluxing of α,β‐unsaturated ketones 2 , 3 , 4 , 5 , 6 with hydrazine derivatives. Newly synthesized compounds were characterized by elemental analyses, spectral data, and screened for their antioxidant and antitumor activities. Geometrical optimizations of the molecular structures for different synthesized compounds were studied.     

Convenient synthesis,antimicrobial evaluation and molecular modeling of some novel quinoline derivatives

α, β-Unsaturated carbonyl compounds 2a, 2b, 3, and 4 were synthesized by the Knoevenagel condensation between 2-substituted quionoline-3-carboxaldehyde 1a and/or 1b with active methylene compounds. In addition, the synthesis of azlactone is achieved starting from 1a and N-acetylglycine. Synthesis of pyridine, pyrene, and pyrimidine derivatives 6–8 were accomplished via one-pot multicomponent reaction of 1b with acetyl acetone, malononitrile, and ammonium acetate; acetophenone, malononitrile, and NaOH; or acetyl acetone and urea in acidic medium. The new synthesized compounds showed good antimicrobial activities. The DFT calculations have been used to predict the electronic properties of the studied compounds.     

Overview of the synthetic routes to sildenafil and its analogues

The biological and medicinal properties of sildenafil and its analogues have prompted enormous research aimed at developing synthetic routes to these heterocycles. This review focuses on the chemical properties associated with this system.     

Measurement of the ground state 2n pickup probability for 28Si+68Zn and its role in sub-barrier fusion enhancement

The ground state and excited state transfer yields for the 2-neutron pickup channel in the ²⁸Si+⁶⁸Zn system have been measured explicitly. The recoil mass separator at the nuclear Science Centre, New Delhi was used for the measurement. A NaI(T1) detector was used for detecting the deexcitation γ’s from the transfer products. The kinematic coincidence technique was employed for the transfer measurement. Simplified coupled channels calculations show that out of all transfer channels the major contribution to the sub-barrier enhancement comes from the ground state 2 neutron pickup channel with a ground state Q-value of+1.83 MeV.     

Comparison of thermomagnetic history effects in weakly pinned single crystals of R 3Rh4Sn13 (R=Yb, Ca)

A comparative study of the thermomagnetic memory effects of J _c in two weakly pinned low T _c superconductors, Ca₃Rh₄Sn₁₃ (CaRhSn) and Yb₃Rh₄Sn₁₃ (YbRhSn), is presented. In both the systems, the peak effect (PE) phenomenon appears as an order-disorder transformation through stepwise amorphization of the flux line lattice (FLL). However, in CaRhSn. we can witness another disorder-driven transition (Bragg glass (BG) to a vortex glass (VG) in a distinct manner as in a single crystal of high T _c YBa₂Cu₃O_7-δ for H‖c.     

Behavior of 2‐iminothiazolidin‐4‐one with different reagents

Annulations of 2‐imino‐4‐thiazolidinone ( 5 ) via cycloaddition followed by cyclocondensation reaction with 1,3‐diphenylpropenone ( 6 ), benzylidenemalonate, and 1,2‐bis(chloromethyl)benzene gave 7 , 19 and 20 , respectively. Reaction of 5 with suitable electrophiles (Mannich bases of arylalkanone), 1,4‐dichlorobenzene (diarylmethylation), and formylation afforded 8 / 9 , 21 / 22 , and 23 , respectively. J. Heterocyclic Chem., (2011).     

Recent Advances in the Chemistry and Synthetic Uses of Amino‐1,3,4‐thiadiazoles

Amino‐1,3,4‐thiadiazoles, although scarce in nature, constitute a group of nitrogen and sulfur heterocyclic compounds that have shown significant biological activities. Their transformations into other biologically active compounds have been exploited. This review describes the work on the synthesis and reactions of amino‐1,3,4‐thiadiazoles as well as their biological evaluation.     

Progress in the chemistry of 4‐ thiazolidinones

This review article includes a recent development in the chemistry of 4‐thiazolidinones. Structure, basicity, synthetic aspects, reactions, and applications were also reported.