16710-11-5Relevant articles and documents
4-arylamino-2-(2-acetoxyethyl)amino-6-methylpyrimidines: Synthesis, deacetylation, and biological activity
Erkin,Krutikov
, p. 1939 - 1943 (2008/09/17)
The reaction of 2-(2-acetoxyethyl)amino-4-chloro-6-methylpyrimidine with aromatic amines leads to a series of 4-arylamino-2-(2-acetoxyethyl)amino-6- methylpyrimidines. Deacetylation of these compounds proceeds in both acidic and basic media. Most of the a
Tautomerism and infrared spectra of thiouracils. Matrix isolation and ab initio studies
Rostkowska,Szczepaniak,Nowak,Leszczynski,KuBulat,Person
, p. 2147 - 2160 (2007/10/02)
A study of the infrared (IR) spectra of a variety of thiouracils isolated in low-temperature inert matrices demonstrated that 2- and 4-thiouracils together with their N1- and N3-methylated derivatives as well as 2,4-dithiouracil exist under these conditions only in the oxothione or dithione tautomeric forms. In contrast, S2- and S4-methylated derivatives under the same conditions exist as a mixture of hydroxy and oxo tautomeric forms. The ratio of concentrations of the tautomers K(o/h) = ([oxo]/[hydroxy]) and the free energy differences, ΔG, were experimentally estimated from the ratio of the absorbances of the NH and OH stretches. The values obtained are K(o/h) = 1.5 and ΔG = -1.7 kJ/mol for 2-(methylthio)uracil and K(o/h) = 0.5 and ΔG = +2.5 kJ/mol for 4-(methylthio)-6-methyluracil. An assignment of the observed infrared bands, particularly those related to the C=S stretching vibrations, is proposed on the basis of the comparison of the matrix spectra from different derivatives and of the spectra calculated by using ab initio methods (3-21G* basis set).
