Purine ribosides, amination

Improvement in fluorination. DAST used for the laboratory-scale synthesis described above is not desirable for industrial synthesis in terms of availability and safety. Thus, we examined the fluorination of 2 -activated nucleoside with triethylamine trihydrogenfluo-ride. The triflate, which was quantitatively obtained from 40, was reacted with 6 equivalents of Et3N 3HF and 3 equivalents of Et3N in ethyl acetate. Fluorination proceeded very smoothly to give 41 in 88% yield [68]. To the best of our knowledge, this is the highest reported yield in the fluorination of a purine riboside at the 2 -position. Next, we treated compound 41 with ammonia to give 42 in almost quantitative yield by simultaneous 6-amination and 3 -benzoyl deprotection, (see Scheme 7.14). 

Purine, 6-bromo-9-/3-D-(2,3,5-tri-0-acetyl)ribofuranosyl-synthesis, 5, 598 Purine, 6-carboxy-reactions, 5, 549 Purine, 8-carboxy-reactions, 5, 549 Purine, 2-chloro-reactions, 5, 561 synthesis, 5, 597 Purine, 6-chloro-alkylation, 5, 529 glycosylation, 5, 529 oxidation, 5, 539 3-oxides reactions, 5, 554 synthesis, 5, 595 reactions, 5, 561, 595 with ammonia, 5, 562 with fluorides, 5, 563 with trimethylamine, 5, 562 9- -D-ribofuranoside synthesis, 5, 560 synthesis, 5, 597, 598 Purine, 8-chloro-amination, 5, 542 Purine, 6-chloro-8-ethoxy-synthesis, 5, 591 Purine, 6-chloro-9-ethyl-dipole moment, 5, 522 Purine, 6-chloro-2-fluoro-riboside... 

Although pyridines and quinolines were first produced during the carbonization of coal, they are now available by synthesis in quantities that far exceed those by the former. Phosphorylated ribosides of hydroxylated and aminated pyrimidines and purines make up the basic structure of ribonucleic and deoxyribonucleic acids. The polycyclic oxaarenes are plant metabolites, while thiaarenes are primarily important components of high-sulfur petroleum that must be removed. 

Adenosine. 9 0-J>-Ribofuranosyt-9H-puriti 6 amine 6-ainino-9 P-D-ribofurano yl 9//-purine 9-/3-D-ribofuranosidoadenine adenine riboside Adenocard. C f-Hi3N 04 mol wt 267.24. 0 44.94%, H 4-90%, N 26.21%, O 23.95 %, Nucleoside widely distributed in nature. From yeast nucleic acid Levene and Bass. Nucleic Acids (New... 

Since many of the above studies implicated the ribonucleotide of AICA as an important intermediate in purine synthetic reactions, it was anticipated that this compound existed in the culture medium of E. coli under sulfonamide stasis. Both the ribonucleotide (AICAR) (Fig. 3) and riboside of AICA were found subsequently in culture filtrates the riboside was the major form in which the amine accumulated and AICAR accounted for only 5% of the total amine formed (69). Phosphatase action probably was responsible for hydrolyzing AICAR to the riboside form, which was then excreted into the culture medium. A p-aminobenzoic acid-requiring (69, 70) and a purine-requiring mutant of E. coli (71,7i) also formed AICA riboside. 

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