Adenine, solution preparation

A dilute solution of the purine adenine in slightly acidic ultra pure water with a nominal concentration of 1.0x10 " M was prepared and transferred to a clear glass sample vial. The samples were placed 7 m away from the excitation laser source. A 532 mu. Coherent VERDI, sohd state diode was used to excite the Raman scattered radiation at the maximum current standoff distance (based on the limitations of the lab room). Figure 9 shows the spectra acquired when 0.1 mL of colloidal silver suspension was added to 10 mL of adenine solution. 

In the present study, water soluble poly(ethyleneimine) derivatives containing uracil, thymine, 5-fluorouracil, hypoxanthine, cytosine, and adenine were prepared and their interactions with polynucleotides, such as poly(A), poly(U), poly(C), poly(I) in natural aqueous solution were investigated. As 5-fluorouracil is known as a famous anticancer agent, it seems to be interest to study the interaction of the polymer containing 5-fluorouracil unit with polynucleotides. The bioactivity of the polymer complex of nucleic acid analogs with polynucleotides will be reported... 

For the investigation of molecular recognition in micelles, adenine derivatives and positively charged (thyminylalkyl)ammonium salts such as shown in Figure 30 were prepared, which were solubilized in sodium dodecyl sulfate (SDS) solutions. Nmr studies have shown that binding occurs in a 1 1 molar ratio in the interior of the micelles as illustrated in Figure 30 (192). 

The reaction to Shapiro s criticisms was quick in coming from the Miller group in La Jolla, California (Nelson et al., 2001). These authors argued that cytosine is easier to prepare from cyanoacetaldehyde and urea at low temperatures than theoretically calculated. They also criticized the incorrect interpretation of the data on the hydrolysis of adenine. As was to be expected, the possibility that solutions could have undergone concentration via evaporation (lagoons or beaches) and freezing out at low temperatures (which also leads to concentration of solutions) are defended. 

The preparation of these solutions is described in the text in section 4.6.7.2. Pipette these successively into 1-cm cuvettes. The absorbance of the mixtures is read twice (at 340 nm) before (ODi) and after (OD2) the addition of glucose-phosphate isomerase. G6P-DH glucose-6-phosphate dehydrogenase, HK hexokinase, NADP nicotinamide adenine dinucleotide, PGI glucose phosphate isomerase, TEA triethanolamine... 

Jain and co-workers prepared highly substituted 1,2-diazetidine derivatives by the photolysis of adenine, which undergoes a [2+2] cycloaddition <1999IJB234>. In aqueous and acidic media adenine undergoes deamination followed by a [2+2] cycloaddition reaction to yield 287, whereas in alkaline solution it afforded direct the [2+2] cycloaddition adduct 288 (Scheme 45) (Equation 35). 

Homopolymers of methacryloyloxyethyl-type monomers containing 5-FU, thymine, or adenine were very stable toward acids and bases, while their hydrophilic copolymers were found to be degraded in aqueous solution under mild conditions to give the derivatives of purine and pyrimidines. The derivatives released from the copolymers were identified by UV spectroscopy as N-hy-droxyethyl derivatives of 5-FU, thymine, or adenine after isolation by preparative TLC. This means that the ester groups of the polymer side chains were hydrolyzed in aqueous solution. 

Reduction of RuC13 xH20 with H2 at 80°C in the presence of a stoichiometric amount of DMSO in DMA solution affords yellow NMe2H2[RuCl3(DMSO)3], the cation being a reduction product of the solvent. The deuterated analogue is readily prepared and X-ray analysis shows the fac S-bonded structure (354).2264 In water loss of chloride produces some [RuCI2(DMSO)3(OH2)] and treatment with Ag+/D20 forms [Ru(DMSO)3(OD2)3]2+.2252,2263 With adenine in DMSO, [Ru-Cl2(ade)(DMSO)3] is produced.2260 ... 

Poly-9-(f -methacryloyloxyethyl)adenine (polyMAOA, 25 a), poly-l-(fi-methacryloyl-oxyethyl)uracil (polyMAOU, 27 a), -thymine (poly-MAOT, 29 a), poly-9-(f -acryloyl-oxyethyl)adenine (polyAOA, 25b), poly-1 -(fi-acryloyloxyethyl)uracil (polyAOU, 27b) and -thymine (polyAOT, 29 b) were prepared by free-radical polymerization of their corresponding monomers26,27). PolyMAOA and polyAOA are soluble in DMSO, ethylene glycol and acidic aqueous solution (below pH 3), while the polymers having uracil and thymine moieties are soluble in DMSO, DMF and alkaline aqueous solution (above pH 10). 

Poly(vinyl alcohols) bonded with nucleic acid bases through phosphate linkages were prepared. Contents of uracil, thymine and hypoxanthine in the polymers were about 50 to 60 mol-%, and that of adenine was about 10%. Interactions of these polymers with DNA in aqueous solution were studied. The apparent hypochromidty was 6.5% for adenine substituted poly(vinyl alcohol) - DNA and 3% for the corresponding uracil substituted derivative83. ... 

Long et al. [87] have studied the association of PS-polymers bearing adenine- and thymine endgroups, prepared via Michael-type addition. The association was followed by H-NMR spectroscopy, relying on the temperature dependency of the imide-protons and revealed strong effects in solution. The formation of 1 1 complexes was proven and extended to other polymers such as poly(acrylates) and their respective melt viscosities [88]. Similar results have been reported for PS-b-Pl [89] and polyisoprenes [90]. hi... 

A solution of adenine (6 g, 44.5 mmol) and Na (1 g, 44.5 g-atom) in abs EtOH (100 mL) was cooled to - 10 C. To this was added dropwise, with continuous stirring, a solution of freshly prepared 4-bromo-2-methylbut-2-ene (5.36 g, 36 mmol) in anhyd EtOH (20 mL). The mixture was allowed to warm to rt and then refluxed overnight. The mixture was concentrated to a small volume, diluted with H O, and extracted several times with CHCI3. The combined CHCI3 extracts were extracted once with H2O and then dried (MgSO ). After filtration, the CHCI3 was evaporated to give a colorless solid yield 3.33 g (46%) mp 188-196 C. 

The reaction fails when the purine contains electron-donating substituents. Thus, 2-(methyl-sulfanyl)adenine does not hydrolyze to any significant extent in 6 M hydrochloric acid. On the other hand, 2-(methylsulfanyl)hypoxanthine is readily converted into xanthine (4) by acid hydrolysis. S -Carboxymethylpurines which arc conveniently prepared from sulfanylpurines in aqueous alkaline solution with chloroacetic acid are used as intermediates in the conversion of sulfanylpurines into hydroxypurines, c.g. the conversions 2 - 3 4, and 5- 6- 1. ... 

This enzyme is monomeric, consisting of one polypeptide apoenzyme and one prosthetic group, a flavin adenine dinucleotide (FAD) moiety (Fig. 2.1), that is nonco-valently bound, with an association constant1 of 3.6 x 106 M. The active holoenzyme can be prepared, or reconstituted, by the addition of FAD to a solution containing the apoenzyme. 

N NMR spectroscopy was used to study the tautomerism of adenine derivatives enriched by the N-15 isotope." These enriched samples were prepared as probes for further biochemical studies. While tautomeric mixtures of N -H and N -H were reported for adenine and 2-MeS-adenine based on the " N NMR spectra, an N -H species was suggested for the solution of S-Br-adenine. These observations were supported by quantum chemical calculation of the individual tautomeric forms for isolated molecules and for the inclusion of solvent effects (both continuum and discrete models). 

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