107287-18-3Relevant articles and documents
Purines. XXVII. Hydrolytic Deamination versus Dimroth Rearrangement in the 9-Substituted Adenine Ring: Effect of an ω-Hydroxyalkyl Group at the 1-Position
Fujii, Tozo,Saito, Tohru,Terahara, Norihiko
, p. 1094 - 1107 (2007/10/02)
In H2O at near neutrality, the 1-(ω-hydroxyalkyl)adenine derivatives 8a, b*HBr and 8c*HClO4 underwent hydrolytic deamination to give the 1-(ω-hydroxyalkyl)hypoxanthine derivatives 10a-c, in competition with the usual Dimroth rearrangement to produce the N6-(ω-hydroxyalkyl)adenine derivatives 9a-c.The rates of these competitive reactions were measured in H2O at various pH's and ionic strenght 1.0 at 40 deg C, and the relative rate of deamination with respect to Dimroth rearrangement was found to increase as the pH of the reaction medium was decreased.Under similar conditions, the corresponding 1-alkyl analogues 8d-g*HClO4 and the 1-(modified benzyl) analogues 8h, i*HBr underwent only Dimroth rearrangement to afford the N6-isomers 9d-i.In the Dimroth rearrangements of all of the substrates 8a, b, d-i*HX (X=Br or ClO4), attack of hydroxide ion on the protonated species (8a, b, d-i*H+) at the 2-position was faster than that on the neutral species by a factor of 100-640.In the reaction of the protonated species, the 1-(ω-hydroxyalkyl)analogues 8a, b*HBr rearranged faster than the corresponding 1-alkyl analogues 8e, f*HClO4 by a factor of 1.6-2.7.It has been concluded that this rate enhancement is attributable solely to the electron-withdrawing effect, and not to intramolecular participation in catalysis, of the hydroxy group in the 1-substituent chain.In the syntheses of 8a, i*HBr from 9-ethyladenine (6) according to a general 1-alkylation procedure, the 7-alkylated products 13 and 16 were also obtained as by-products in 9percent and 6percent yields, respectively.Keywords - 1,9-disubstituted adenine; 9-substituted 1-(ω-hydroxyalkyl)adenine; Dimroth rearrangement; hydrolytic deamination; 9-substituted 1-(ω-hydroxyalkyl)hypoxanthine; kinetic study; acid dissociation constant; UV; 9-ethyladenine 1-alkylation; 9-ethyladenine 7-alkylation
