ABSTRACT4-Arylmethylene-2-phenyl-2-oxazolin-5-ones 1 a,b reacted with some active methylene reagents to afford pyrrolidine-3,5-dione, pywolo[2,3-b] Polyfunctionally substituted pyrrolones are interesting as potential pharmaceuticals [ 1-31 and intermediates in the dye industry [4]. In previous work, it has been reported that 4-phenylmethylene-2-oxazolin-5-one (lc) reacts with ethyl cyanoacetate (2a) in benzene in the presence of potassium metal to yield an acyclic p-ketoester, which could readily be cyclized to give an amino pyrrolone or pyrrolidine-3,5-dione, depending on the reaction conditions [ 5 ] . Attempted extension of this synthesis, utilizing benzoylacetonitrile (2b), afforded only products of a Michael addition across the double bond in 1 [5]. In continuation of our previous work [6,7], we report here results of our
Following the modified model used in our previous paper for the study of laser-induced breakdown of molecular nitrogen, in this work we present the influence of secondary ionization processes on the breakdown phenomenon. The analysis is based on the calculation of the electron energy distribution function and its parameters for laser wavelengths covering the range 266-1064 nm, in irradiated molecular nitrogen at atmospheric pressure. The result of computations revealed that no evidence is observed for collision and photoionization processes of ground-state molecules. Under the experimental conditions applied in this analysis, collision processes lead only to the population of excited states. Breakdown of nitrogen at laser wavelengths 532, 355 and 266 nm proceeds totally via photoionization of the excited states. For
= 1064 nm, electron growth is obtained due to multi-photoionization of the excited states, in addition to the contribution of collisional ionization of these states.
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