A highly practical and efficient preparation of 6-methy-4H-thiochromene and 7-methyl-thiochromene[2,3-d]pyrimidine derivatives was developed via a multi-component reaction of 3-methyl-thiophenol (1), aldehydes (2), and malononitrile (3). A series of pyrimidine nucleoside, thiochromene[2,3-d]pyrimidine and thiochromene[2,3-d]pyrimidine-10-sulfone was efficiently obtained. These hybrid compounds ...

The synthetic route for introduction of fluorophenylalkyl (compounds 5, 7, 14 and 15) and fluorophenylalkenyl (compounds 4E and 13) side chains at C-6 of the pyrimidine nucleus involved the lithiation of the pyrimidine derivatives 1, 2 and 11 and subsequent nucleophilic addition or substitution reactions of the organolithium intermediate thus obtained with 2-fluorophenylacetone, 4-fluoroacetoph...

The relationship between pyrimidine dimers (measured as endonuclease-sensitive sites) and newly-synthesized DNA has been examined in several different ways, with the following results:- 1. After UV-irradiation of normal human fibroblasts the frequency of pyrimidine dimer sites in sections of DNA which have been synthesized immediately before the UV-irradiation is similar to that in the bulk DNA...

We have investigated the hypothesis that pyrimidine dinucleotides are avoided in light-exposed genomes as the result of selective pressure due to high ultraviolet (UV) exposure. The main damage to DNA produced by UV radiation is known to be the formation of pyrimidine photoproducts: it is estimated that about 10 dimers per minute are formed in an Escherichia coli chromosome exposed to the UV li...

In the crystal structure of the title compound, [Ni(2)(NCS)(4)(C(4)H(4)N(2))(3)(CH(3)OH)(2)](n), each nickel(II) cation is coordinated by three N-bonded pyrimidine ligands, two N-bonded thio-cyanate anions and one O-bonded methanol mol-ecule in a distorted octa-hedral environment. The asymmetric unit consists of one nickel cation, two thio-cyanate anions and one methanol mol-ecule in general po...

Nucleoside : purine (pyrimidine) deoxyribosyltransferase activity (EC 2.4.2.6.) has been demonstrated in bacteria by a number of investigators (l-5). Similar activity in mammalian tissues was reported by deVerdier and Potter (6). With the mammalian enzyme, however, the substrate specificity of the transfer reaction appeared to be restricted to pyrimidine bases and their deoxyribonucleosides. Tr...

Considerable knowledge concerning purine metabolism has been obtained from chemical and isotopic studies of urinary uric acid. Corresponding information in man is lacking for the closely related field of pyrimidine metabolism. The availability of ring-labeled orotic acid as a specific pyrimidine precursor (1), together with the presence of pseudouridine (5-ribosyluracil) and uracil, as specific...

In the title mol-ecule, C(11)H(11)ClN(2)O, the pyrido[1,2-a]pyrimidine ring system is planar (maximum deviation = 0.0148 Å) and the methyl C and carbonyl O atoms are nearly coplanar to it. The chloro-ethyl side chain is in a synclinal conformation, nearly orthogonal to the pyrimidine ring, with a dihedral angle between the chloro-ethyl side chain and the pyrimidine ring of 88.5 (1)°. Weak inter...