2,6-Diamino-purine

Purine, 2-chloro-8-thioxo-7,8-dihydro-synthesis, 5, 578 Purine, 6-cyano-reactions, 5, 548 synthesis, 5, 593 Purine, 8-cyano-reactions, 5, 548 Purine, 8-deoxyribosyl-synthesis, 5, 585 Purine, 2,8-dialkyl-synthesis, 5, 568 Purine, 2,6-diamino-biological activity, 5, 604 reactions... 

H-Purin 2,6-Diamino-8-trifluorme-thyl- E9b/2, 338 [(NH2)4-pyrimidin+ F3C —COOH)... 

The 3-amino group of 3,4-diamino-2//-pyrido[l,2-u]pyrimidin-2-ones 216, obtained from 3-nitroso derivatives by reduction with Na2S204 in 30% NH4OH at 70-80 °C, was acylated with acyl chlorides, and the acylated products 217 were cyclized to pyrido[2,l-Z)]purin-10-ones 218 by treatment with NaOMe (95JHC1725). 

Bei der Reduktion von Purinen wird zumeist der Funfring aufgespalten. Die galvano-statische Elektrolyse (3—4 A/8 V fur mehrere Stdn.) von 2,8-Diamino-purin in 25,8 n Schwefelsaure an Blei-Kathoden liefert neben 2,8-Diamino-1,2,3,4,5,6-hexahydro-9H-purin 2-Amino-5-guanidino-6-oxo-3,4,5,6-tetrahydro- und 2-Amino-5-guanidino-3,4-dihydro-pyrimidin (nur das Tetrahydro-pyrimidin-Derivat ist abtrennbar (Totalausbeute -45% d.Th.)3. 

The two overwhelming oxidation products of the purine moiety of dGuo 37 arising from the transformation of guanine radical cations 38 were isolated and identified as 2,2-diamino-4-[(2-deoxy-/l-D-eryfhro-pentofura-nosyl)amino]-5(2H)-oxazolone (41) and its precursor 2-amino-5-[(2-deoxy-... 

One-electron oxidation of the adenine moiety of DNA and 2 -deoxyadenos-ine (dAdo) (45) gives rise to related purine radical cations 46 that may undergo either hydration to generate 8-hydroxy-7,8-dihydroadenyl radicals (47) or deprotonation to give rise to the 6-aminyl radicals 50. The formation of 8-oxo-7,8-dihydro-2 -deoxyadenosine (8-oxodAdo) (48) and 4,6-diamino-5-formamidopyrimidine (FapyAde) (49) is likely explained in terms of oxidation and reduction of 8-hydroxy-7,8-dihydroadenyl precursor radicals 47, respectively [90]. Another modified nucleoside that was found to be generated upon type I mediated one-electron oxidation of 45 by photoexcited riboflavin and menadione is 2 -deoxyinosine (51) [29]. The latter nucleoside is likely to arise from deamination of 6-aminyl radicals (50). Overall, the yield of formation of 8-oxodAdo 48 and FapyAde 49 upon one-electron oxidation of DNA is about 10-fold-lower than that of 8-oxodGuo 44 and FapyGua 43, similar to OH radical mediated reactions [91]. 

Hydroxy-perhydropyrimido[2,Tr-][l,4]oxazine condensed into the pentacyclic compound 319 on heating in aqueous solution. The 9-OH-9-Me analogue did not undergo this reaction < 1996H(43) 1991 >. 7,8-Diamino-3,4-dihydro-277-pyrimido[2,1 -b [ 1,3]thiazin-6-one and 8,9-diamino-3,4-dihydro-2/7,6/7-pyrimido[6, -b][ 1,3]thiazin-6-one when reacted with benzamidine. HC1 in a melt at 220 °C in the presence of anhydrous NaOAc formed the purine derivatives 320 and 321, respectively <1996JME2529>. 

A general and efficient solid-phase synthesis of A-9-substituted 2,8-diamino purines 62 has been described. The key synthetic transformation uses a carbodiimide-mediated cyclization of a thiourea 60. The reaction was performed using microwave reaction conditions on solid phase <06TL8897>. 

Heating 7,8-diamino-1,3-dimethylxanthine 802 with hydrochloric acid gave azapteridine 803, which on treatment with alkylamines gave [1,2,4]-triazino[2,3-/]purines 804 (87CPB4031). 

Bei der Synthese von Adenin-[8-18C] aus 4.6-Diamino-(5-formamido-[18C])-pyrimidin (I) durch Erhitzen in Formamid stellten Cavalieri imd Brown (44) einen erheblichen Austausch zwischen I und dem Formamid fest, was eine Umamidierung darstellt. Nur 25 % des 13C-t)berschusses von I wurden im Adenin wiedergefunden. Durch Verwendung anderer Losungsmittel an Stelle von Formamid kann der Austausch, der ins-besondere bei der Synthese hochradioaktiver, in 9-Stellung14C-markierter Purine sehr storend ist, vermieden werden [vgl. (215)]. 

This procedure provides a convenient synthesis of aminomalononitrile, which has been demonstrated to be a useful intermediate for the preparation of substituted imidazoles, thiazoles, oxazoles, purines, and purine-related heterocycles.2 It is also a convenient starting material for the preparation of diamino-maleonitrile.2, 4... 

Synthesis of the 2,6-Diamino-9//-purine Peptide Nucleic Acid Monomer... 

Studies by Klett et al. (28) with a synthetic d(A-T) copolymer in which diamino purine replaced adenine at the 3 end and by Deutscher and Kornberg (27) with 3 -phosphoryl-terminated polynucleotides led to the finding that purified preparations of E. coli DNA polymerase possess a 5 - 3 exonucleolytic activity. In the latter studies DNA preparations with 3 -phosphoryl termini introduced by the action of staphylococcal nuclease (tf) and therefore insensitive to 3 - 5 exonuclease action were... 

Aryl-7,8-diamino-1,2,4-triazololl, 5-c]pyrimidines (97 R= H) selectively acylate on the 8-amino group to give the amides (97 R= R CO) which cyclise on heating with PPA to yield 2-aryl-8-fIuorobenzyl-l,2,4-triazolo[5,l-/]purines (98) [94JHC1171],... 

The syntheses of 1,3-dipropyl-l//,3//-pyrazino-, pyrid0 5 pynmido-, and pyrrolo[2,1 /]purine-2,4-diones starting from 5,6-diamino-l,3-dipropylpyrimidine-2,4-dione and 6-chloro-l,3-dipropyl-pyrimidine-2,4-dione have been described (Scheme 15) <94JHC8l>. A new route to 1,3-dipropyl-1H, 3/f-pyrido- (or pyrazino-) [T,2 -l,2]pyrimidino[4,5-d]pyrimidino-2,4,5-triones has also been developed (Scheme 16). 

Escherichia coli B was incubated with 2,6-diaminopurine (XXIV), and 6-amino-2-(methylamino)-9-(5-0-phospho-D-ribosyl)purine (XXV) was isolated from the acid-soluble extract of the cells. 5-Nucleotidase liberated a nucleoside containing D-ribose. Hydrolysis of the nucleoside (or nucleotide) with N hydrochloric acid liberated 6-amino-2-(methylamino)purine, which was identified by paper chromatography and by its ultraviolet absorption spectrum. The chromatographic and ion-exchange behavior of the extract also suggested the presence of either a pyrophosphate or a triphosphate of the 6-amino-2-methylamino-(D-ribosyl)purine. In a similar manner, 2,6-diamino-9-(5-0-phospho-D-ribosyl)purine (XXVI) was isolated and identified, together with its possible pyrophosphate or triphosphate. 2,6-... 

The synthesis of 6-amino-2-methylamino-purine from 2,6-diamino-purine and the corresponding nucleotides was also demonstrated in crude extracts of Escherichia coli B. 

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