Pyrimidine derivatives, adsorption

Photochemical transformations were carried out to determine whether the 4-amino-pyrimidine wave I reduction product is susceptible to photochemical oxidation, as in the case of other pyrimidine derivatives 2> 3,5 96). The resulting data are summarized in Table III. Irradiation at 300 nm or 254 nm of a freshly electrolyzed solution subsequently brought to pH 0.5, in the presence of mercury, did in fact lead to partial (about 50 %) regeneration of 4-aminopyrimidine. Such partial regeneration, however, also occurred spontaneously in the presence, but not in the absence, of air (oxygen). The fact that this reaction occurred only in the presence of mercury is rather puzzling, but points to involvement of some adsorption process(es). 

Consideration of the inhibitor concentration markedly improves the quality of the correlations. Figure 9-51 shows the relationship between experimental and estimated inhibition efficiencies of pyrimidine derivatives (Lukovits et al., 1997) obtained by assuming the Langmuir adsorption. A similar technique can be used for the Free - Wilson variables (Lukovits et al., 1995), again yielding much better results than those obtained using a fixed concentration approach (Dupin et al., 1982). 

Other applications involved photon adsorption or emission. An FTIR spectroscopic study of the adsorption of pyrimidine on loughlinite was conducted to characterize the surface interaction <04JMS147>, and new mono-, poly-, and macrocyclic mesoionic pyrimidinium-olates were prepared and their propensity toward photochemical rearrangement to his(P-lactam) derivatives was studied <04710011>. Sequential nucleophilic addition of aryl anions to 2-methylthiopyrimidine 76 followed hy DDQ oxidation gave 4-aryl-2-methylthiopyrimidines, then... 

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