5-hydroxy methyluracil

Thymine-uraciluria in R.E, The gas chromatogram of the trimethyl si lylated organic acids displayed two mediimi size abnormal peaks, which turned out to be due to uracil and thymine according to GLC-MS analysis. The two-dimensional thin-layer chromatogram showed except uracil and thymine a third abnormal spot. Isolation of this compound from a two-dimensional chromatogram, followed by trimethylsilylation and GLC-MS showed the compound to be 5-hydroxy-methyluracil. This compound is not extracted with ethylacetate and is therefore absent in the gas chromatogram. 

Plant The major degradation products of [2- C]terbacil identified in alfalfa using a mass spectrometer were (% of applied amount) 3-/er/-butyl-5-chloro-6-hydroxymethyluracil (11.9) and 6-chloro-2,3-dihydro-7-(hydroxymethyl)-3,3-dimethyl-5//-oxazolo[3,2-a]pyrimidin-5-one (41.2). Two additional compounds tentatively identified by TLC were 3-/er/-butyl-6-hydroxy-methyluracil and 6-chloro-2,3-dihydro-7-methyl-3,3-dimethyl-5//-oxazolo[3,2-a]pyrimidin-5-one (Rhodes, 1977). 

Bromo -3 - (3 -hydroxy-1 -methylpropyl) -6-methyluracil, see Bromacil 2-Bromo-3-hydroxypropene, see l,2-Dibromo-3-chloropropane... 

CASRN 314-40-9 molecular formula C9Hi3BrN202 FW 261.12 Soil Metabolites tentatively identified in soil were 5-bromo-3-(3-hydroxy-l-methylpropyl)-6-methyluracil, 5-bromo-3-5ec-butyl-6-hydroxymethyluracil, 5-bromo-3-(2-hydroxy-l-methylprop-yl)-6-methyluracil, and carbon dioxide. The presence of uracil products suggests that bromacil was degraded via hydroxylation of the side chain alkyl groups. In the laboratory, 25.3% of C-bromacil degraded in soil to carbon dioxide after 9 wk but mineralization in the field was not observed. The half-life of bromacil in a silt loam was 5-6 months (Gardiner et al, 1969). 

Cytosine (2-hydroxy-6-amino-pyrimidine), uracil (2,6-dihydroxypyrimidine), and thymine (5-methyluracil) are pyrimidine derivatives adenine (6-aminopurine), guanine (2-amino-6-hy-droxypurine), and xanthine (2,6-dihydroxypurine) are purine derivatives (Fig. 5). 

Tertiary amines boost the reactivity of POCl3 in the substitution of hydroxy pyrimidines774. Thus 6-methyluracil is reacted with POCl3 in the presence of tri- -propylamine to yield 2,4-dichloro-6-methylpyrimidine, while triethylamine gives some amination products as well (equation 105)775. 

Fig. 15.1. The four bases found in the nucleic acids. Uracil occurs in RNA and is substituted by the analogous thymine (5-methyluracil) in DNA. Uracil is the keto tautomer of 2,4-dihydroxy pyrimidine with two donors N(1)H, N(3)H and two acceptors 0(2), 0(4). Cytosine is the keto tautomer of 4-amino, 2-hydroxy pyrimidine with three donors N(4)H2, N(1)H and two acceptors 0(2), N(3). Adenine is 6-aminopurine with three donors N(6)H2, N(9)H and three acceptors N(l), N(3), N(7). Guanine is the keto tautomer of 2-amino, 6-hydroxy purine with three donors N(2)H2, N(9)H and three acceptors, N(3), N(7), 0(6). In the nucleosides, pyrimidine N(l) and purine N(9) are substituted by ribose or deoxyribose (see Fig. 17.1)...

The absorption of uracil on the Si(0 0 1) surface has been investigated by density-functional theory calculations using a plane-wave basis in conjunction with ultrasoft pseudopotentials. The absorption of dihydroxy tautomer is energetically not favored. However, the absorption of hydroxy(oxo) tautomers is favorable if two Si dimers are involved in the reaction thus, the presence of these tautomers is more likely on the Si(00 1) surface than in the gas phase (03JPC(B)5031). A systematic theoretical investigation of the effects of intermolecular association on the structure of uracil and its methyl derivatives combined with the solid-state studies indicated that the preferred associations are dimer for 1-methyluracil, trimer for thymine, and hexamer for uracil (99ACSA57). 

Thymine (2,6-hydroxy-5-methylpyrimidine or 5-methyluracil) was first isolated in 1893 by Kassel and Newman from nucleic acid hydrolysates obtained from calf thymus. Thymine is found in all DNA and is rarely present in RNA. It has never been found free in nature except in sponges in the form of xyloside. 

C10H13N5, N -(A -Isopentenyl)adeninej 38B, 427 C10H13N5, 6-Amino-3-dimethylallylpurine, 43B, 521 Cl0H14CI2N1oO, Adenine hydrochloride hemihydrate, 11, 723 15, 492 CioHi N,05, cis syn 6-Methyluracil photodimer monohydrate, 37B, 227 Cl0H14N,05, 5a-Hydroxy-6,4 -(5 -methylpyrimidin-2 -one)-dihydrothy-mine monohydrate, 34B, 240... 

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