Hypoxanthine 2-methyl

Hypoxanthine, 7-ethyl-synthesis, 5, 584 Hypoxanthine, 1-methyl-deuterium-hydrogen exchange, 5, 527 synthesis, 5, 594 Hypoxanthine, 2-methyl-methylation, 5, 532 synthesis, 5, 587 Hypoxanthine, 3-methyl-free radical methylation, 5, 544 irradiation, 5, 543 synthesis, 5, 584 Hypoxanthine, 8-methyl-synthesis, 5, 584 Hypoxanthine, 9-methyl-methylation, 5, 532... 

Figure 12 Gradient separation of bases, nucleosides and nucleoside mono- and polyphosphates. Column 0.6 x 45 cm. Aminex A-14 (20 3 p) in the chloride form. Eluent 0.1 M 2-methyl-2-amino-l-propanol delivered in a gradient from pH 9.9-100 mM NaCl to pH 10.0-400 mM NaCl. Flow rate 100 ml/hr. Temperature 55°C. Detection UV at 254 nm. Abbreviations (Cyt) cytosine, (Cyd) cytidine, (Ado) adenosine, (Urd) uridine, (Thyd) thymidine, (Ura) uracil, (CMP) cytidine monophosphate, (Gua) guanine, (Guo) guanosine, (Xan) xanthine, (Hyp) hypoxanthine, (Ino) inosine, (Ade) adenosine, (UMP) uridine monophosphate, (CDP) cytidine diphosphate, (AMP) adenosine monophosphate, (GMP) guanosine monophosphate, (IMP) inosine monophosphate, (CTP) cytidine triphosphate, (ADP) adenosine diphosphate, (UDP) uridine monophosphate, (GDP) guanosine diphosphate, (UTP) uridine triphosphate, (ATP) adenosine triphosphate, (GTP), guanosine triphosphate. (Reproduced with permission of Elsevier Science from Floridi, A., Palmerini, C. A., and Fini, C., /. Chromatogr., 138, 203, 1977.)...

PES has been applied to study biologically active molecules with amino groups and their constituents like nucleic bases and related compounds (e.g. adenine, guanine, thymine, cytosine, hypoxanthine and their methyl derivatives)113-120 and amino acids92,121,122 or their methyl esters123. 

Fig. 13.1 Pathways of thiopurine metabolism. The positions of two polymorphically expressed enzymes, TPMT (thiopurine methyl transferase) and ITPA (inosine triphosphate pyrophosphatase), are shown. HGPRT, hypoxanthine guanine phosphoribosyl transferase 6-TIDP, 6-thioi-nosine diphosphate 6-TIMP, 6-thioinosine monophosphate 6-TITP, 6-thio inosine trinophosphate...

The sugar specificity of RNase Tx appears to require a 2 -hydroxyl group for the substrate because DNA is not attacked by RNase Tx. This is consistent with the intermediary formation of 2, 3 -cyclic phosphate and also with the finding that 2 -0-methylated guanylyl bonds in tRNA is resistant to the enzyme (48)- Holy and Sorm (49) found that RNase Tx did not attack L-guanosine 2, 3 -cyclic phosphate and L-inosine 2, 3 -cyclic phosphate. They found further that RNase Tx split 9-(a-L-lyxo-furanosyl)-hypoxanthine 2, 3 -cyclic phosphate but not the D-lyxofura-nose derivative, and they concluded that the substrate molecule was fixed at least to three regions of RNase Tx (50). 

Hu et al. [84] Hypoxanthine Fish Xanthine oxidase/within a polyaniline film on the electrode surface by electropolymerisation Sodium montmorillonite-methyl viologen carbon paste modified electrode/-0.72V vs. Ag/ AgCl Methyl viologen... 

This information, and recognition that the only source of the methyl groups was through reductive hydrolysis of the methine group in the pyrimidine ring of hypoxanthine, led to the postulation of structures XX VII and XXVIII, respectively, for the... 

Adenine and adenosine were converted into hypoxanthine and inosine respectively on a copper-montmorillonite support, adsorption being accompanied by oxidation <91N121>. 7-Benzyl-2-iso-butyryl-3-methylguanine lost the 3-methyl group when heated in toluene with 2-3-5-tri-0-ace-tylribosyl bromide <85Mi 711-05). 

Under basic conditions, hypoxanthin (8.108), its 1- and 3-methyl derivatives, and 5-chloro-l-methylhypoxanthin,3 all underwent exchange at the... 

FIGURE 7-5. A 0 to 10% gradient separation of polar compounds. Components (1.0 p.g each) (1) uracil, (2) hypoxanthine, (3) 3-methyl xanthine, (4) theobromine, (5) theophylline, and (6) /3-hydroxyethyl theophylline. Solvent A 0.01 M sodium ace-tate/water. Solvent B acetonitrile. Flow rate 2.0 mL/min. Gradient 0-10% solvent B using a linear shape (top line). Run time 50 min. Injection volume 15 p.L. Column Radial-Pak Resolve Cig (10 /xm) 8 mm ID x 10 cm. Detector UV at 254 nm, 0.1 AUFS. (Reproduced from reference 1 with permission.)... 

The centrosymmetrical AA42 base pair is mostly observed in complexes 9-ethyl-8-bromo-adenine with 9-ethyl-8-bromo-hypoxanthine [EBAEBH1 9-methyl-adenine with l-methyl-4-thiouracil [SURMAD101 and with 2-thiohydantoin [BIFYOE] 9-ethyladenine with parabanic acid [EADPBA] 3-(adenin-9-yl)pro-piontryptamide [ADPRTR]. 

Hypoxanthine can be methylated using methyl iodide [101] and the resulting... 

The naturally occurring purines fall into 4 main groups. (1) Simple substituted derivatives of purine (1) such as adenine (2) and various 6-AT-substituted derivatives. (2) Monoxo-dihydropurines such as hypoxanthine (3), guanine (4), and isoguanine (5). f3) Dioxotetra-hydropurines such as xanthine (6) and methylated derivatives including the 3,7-dimethyl derivative theobromine (7), 1,3-dimethylxanthine or theophylline f8), and 1,3,7-trimethylxanthine or caffeine (9). (4) Trioxohexahydropurines such as uric acid (10). 

Tetrahydropyranylation of hypoxanthine in DMSO obcurs with acidic catalysis and 2,3-dihydropyran, to produce l,9-bis(tetrahydropyran-2-yl)hypoxanthine (105) and the corresponding 1,7 isomer (106) (66JOC268s). Alkylation studies of 2-oxodihydropurine have been limited and no data are available for the 8-oxo isomer. Methylation of the 2-oxo derivative with methyl iodide in alkaline solution at 80 °C leads to the 7-methyl, then the 3,7-dimethyl derivatives. 

Thiation of purine, 6-methyl- or 2-amino-purines with hot sulfur leads to the 8-thioxo derivatives (64JOC3209). The reaction failed with guanine, hypoxanthine and 6-chloropurine but was successful with 1,9-dimethyl-, 7,9-dibenzyl- and 7,9-dimethyl-hypoxanthines... 

---