6-Aminouracils

The methylated 5-aminouracils (110 and 113) were also converted into similar aminomethylenemalonates which cyclized to yield th corresponding pyridopyrimidines (121 and 122, R = COOEt). 

Z)wzoMraci7 — Diazotization of 5-aminouracil yields 5-diazouracU [316—318] (XXXIX). 

Aminouracil produces a block in the mitotic cycle of various plants. For example, cessation of mitosis occurred in Vida faba roots incubated 24 h with this compound [392—394]. Depending on different experimental conditions, thymidine or thymidylic acid may or may not alleviate these effects [392—394]. It was concluded that 5-aminouracil depressed the rate of DNA synthesis, which led to an accumulation of cells in the S phase. After removal of the agent, DNA synthesis resumed. Similar results have been observed with Allium cepa and Haplopappus gracilis [395, 396]. Inhibition of guanosine incorporation into RNA of meristematic cells in Vida faba by 5-aminouracil was also reported [397]. 

The deoxyriboside derivative of 5-methylaminouracil (LlVa) is a specific antiherpes agent [399]. The aglycone itself (LIVb) as well as 5-aminouracil, however, has no antiviral activity [399]. 

Aminosulfur trifluorides, 19 192 syntheses and properties of, 14 347-348 Aminotroponeimines, 32 29 5-Aminouracil, astatination, 31 75 Aminousulfanuryl fluoride ions, 19 226,... 

Hayon447 to absorb in this UV region. Similar measurements have been made for a number derivatives of uracil (5,6-dihydro, 1-, 3-, and 6-methyl, 1,3-dimethyl-, and 5-aminouracil, orotic acid, barbituric and isobarbituric acids also see similar measurements448 on 5-bromouracil and its iV-methyl derivatives), thymine itself and its derivatives (5,6-dihydro, 2-methylthymine). In the case of cytosine, Hayon447 has very tentatively suggested that species 47 and 48 are obtained on pulse radiolysis of the solution at pH 5.5, and 49 at pH 13.3. 

Preparation of 5-[bis(2-Hydroxyethyl)Amino] Uracil 20 grams (0.157 mol) of 5-aminouracil was mixed with 350 ml of water, 23 ml of glacial acetic acid, and 160 ml of ethylene oxide in a one-liter flask immersed in an ice bath. The reaction mixture was stirred and allowed to come to room temperature slowly (as the ice melted), and stirring was continued for two days. A clear solution resulted to which was added 250 ml of water and 60 grams of Dowex-50 in the acid form. The mixture was stirred for 15 minutes, and the resin was collected on a filter. It was washed with water and the crude 5-[bis(2-hydroxyethyl)amino] uracil was eluted with a 10% aqueous solution of ammonium hydroxide. This eluate was evaporated to dryness, and the solid that remained was heated with 350 milliliters of isopropyl alcohol. 

Capsules Fludiazepam HPLC Extract powder with H20, filter Cl8, Pharmex 0.05A/P04, pH 4.5, 1 ml/min 300 nm ISTD-5-aminouracil, stability review [499] USP 23 [889,890] Structurally similar to flunitrazepam expected to have similar chromatographic behavior [493 ... 

Thymine Uracil 5-Bromouracil 5-Aminouracil (Adenine) (Hypoxanthine) (6-Methyluracil ) (Purine ) Thymine Uracil 5-Bromouracil 5-Aminouracil 5-Bromouracil Adenine Guanine Hypoxanthine 6-Methyluracil Uracil Adenine Hypoxanthine Purine (Adenine)... 

The most common synthetic approaches to both types of pyrimidopyrimidine have been described in CHEC-I and in review articles by Delia . In addition some new strategies in the preparation of pyrimido[4,5-rf]pyrimidines have been developed in the last few years. A new approach is the aza-Wittig-type reaction of iminophosphoranes of 5-aminouracils with aromatic isocyanates which leads to functionalized pyrimido[4,5-rf]pyrimidines. Ethyl 1,3-dimethyl-6-(triphenylphosphoranylideneamino)-uracil-5-carboxylate (105) reacts with isocyanates via adduct (106a) intermediates to afford 7-ethoxypyrimido[4,5-. 

The readiness of amidine formation in reactions of lactim ethers with amines has been used in the synthesis of 8,9-poly methylene-purines.97 Attempts to condense 2 (R = Me) with uramil and l,3-dimethyl-4,5-diaminouracil failed.97 Lactim ethers were also found not to react with derivatives of 5-aminouracil, probably due to the low basicity of the latter.97... 

Chloroacetaldehyde oxime, 2-carbon cyclization using, 55, 287 N-Chloroamides, chlorinating agents for pyrroles, 57, 326 N-Chloroamines radical cyclizations from, 58, 19 radicals by photolysis of, 58, 10 Chlorocarbonylsulfenyl chloride, reaction with 5-aminouracils, 55, 153 Chlorodimethylsulfonium chloride,... 

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