an efficient synthesis of polyhydroquinoline derivatives is achieved via hantzsch condensation reaction between aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of catalytic amount of sfhs in ethanol. this method gives remarkable advantages such as shorter reaction time, simple workup procedure and good to excellent yields. furthermore the catalyst can be recovered c...

maltose as an efficient, available, cheap and eco-friendly catalyst has been applied for the synthesis of 3,4,5-substituted furan-2(5h)one derivatives via a one-pot three-component reaction of arylamines, aromatic aldehydes and dialkyl acetylenedicarboxylates in water. this method has notable advantages in terms of simple workup, no need for column chromatography, short reaction time and high y...

sulfonic acid functionalized sba-15 (sba-pr-so3h) as a new nanoporous acid catalyst was used in the one-pot synthesis of polyhydroquinolines derivatives via the hantzsch four component condensation reaction of aldehydes, b-ketoesters, dimedone and ammonium acetate under solvent free conditions with short reaction time in excellent yields. sba-pr-so3h was proved to be an efficient heterogeneous ...

Kornblum's time estimation paradigm, together with the so-called 'race model', provides an appealing alternative for measuring the 'cut-off' which separates 'true' reaction times from anticipatory reaction times. However, the model is not precise enough to reveal the relation between the signal intensity and the 'cut-off'. Accordingly, Kornblum's model is extended with an emphasis on the measur...

an improved, simple, and facile synthesis of 3,4-dihydropyrimidin-2(1h)-ones by employing three-component, one-pot condensation reaction of β-keto ester, aromatic aldehydes, and urea or n-methylurea using lacl3/clch2cooh as an inexpensive and green chemistry catalyst system under solvent-free conditions described. compared with the classicalbiginelli reaction conditions, this method has the adv...

A highly efficient, simple and clean solvent-free protocol for the synthesis of polyhydroquinolines is described. The one-pot multi-component condensation reaction between arylaldehydes, dimedone (5,5-dimethylcyclohexane-1,3-dione), β-ketoesters and ammonium acetate in the presence of catalytic amount of (2.5 mol%) melamine trisulfonic acid (MTSA) as a recyclable, green and attractive sulfonic ...

radar transmitters emit high-power radiofrequency radiation by creation of a high-voltage and high-frequency alternating electrical current.health effects of occupational exposure to military radar were investigated. visual reaction time was recorded with a simple blind computer-assisted-visual reaction time test. to assess the short-term memory, modified wechsler memory scale test was performe...