16710-11-5Relevant academic research and scientific papers
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
6-Substituted and 5,6-disubstituted derivatives of uridine: Stereoselective synthesis, interaction with uridine phosphorylase, and in vitro antitumor activity
Felczak, Krzysztof,Drabikowska, Alicja K.,Vilpo, Juhani A.,Kulikowski, Tadeusz,Shugar, David
, p. 1720 - 1728 (2007/10/03)
Stereoselective procedures are described for the synthesis of 6- alkyluridines by Lewis acid-catalyzed condensation of (a) trimethylsilylated 6-alkyl-4-alkylthiouracils with 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D- ribofuranose (ABR) and (b) trimethylsilylated 6-alkyl-3-benzyluracils with ABR. The 4-methylthio group was subsequently removed with the use of 1 N trifluoroacetic acid and the 3-benzyl group by a new modified procedure with the use of the complex BBr3-THF. Furthermore, 6-(hydroxymethyl)uridine (39) and 5-fluoro-6-(hydroxymethyl)uridine (40) were obtained by sequential oxidation with SeO2 and reduction with tetrabutylammonium borohydride of the 6-methyl group of 6-methyluridine (5) and 5-fluoro-6-methyluridine (35), and their corresponding 6-fluoromethyl congeners 41 and 42 were obtained by DAST treatment of 39 and 40, respectively. For all the foregoing nucleosides in the fixed syn conformation about the glycosyl bond, 1H NMR spectroscopy further demonstrated that the pentose rings exist predominantly in the conformation N (3'-endo). Most of the nucleosides were weak substrates of Escherichia coli pyrimidine nucleoside phosphorylase. Enhanced susceptibility to phosphorolysis was exhibited by two of them, 39 and 41, with 6-CH2OH and 6-CH2F substituents capable of formation of an additional hydrogen bond with the enzyme. The 5-fluoro-6-substituted uridines were the poorest substrates. Cytotoxicities of the nucleosides were examined vs the human tumor cell lines MOLT-3, U-937, K-562, and IM-9, as well as PHA-stimulated human lymphocytes. Two of the analogues, 5-fluoro-6-(fluoromethyl)uridine (42) and 5-fluoro-6- (hydroxymethyl)uridine (40), exhibited cytotoxicities comparable to that of 5-fluorouracil.
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).
