Regioselective and efficient synthesis of N 7-substituted adenines, guanines, and 6-mercaptopurines

Study of Direct N7 Regioselective tert-Alkylation of 6-Substituted Purines and Their Modification at Position C6 through O, S, N, and C Substituents

“…First, we focused on the preparation of hypoxanthine analogue 13 , which was prepared by the alkaline hydrolysis of 2 . Because of the low stability of tert -butyl at position N 7 in acidic solutions, we cannot afford to carry out this hydrolysis with HCOOH, which has been utilized for analogous 7-alkyl-6-chloropurines, where alkyl represents methyl, allyl, propargyl, ester, and keto groups . From this point of view, the tert -butyl group is specific.…”

Design, Synthesis, Antiviral, and Cytostatic Evaluation of Novel Isoxazolidine Analogs of Homonucleotides

“…All N ‐allylated nucleobases 15 , except for 15r , have already been described in the literature . For the purpose of this study, they were prepared by allylation of commercially available nucleobases employing four different protocols (Scheme ; for the list of applied nucleobases ( B ) see Table ).…”

“…Compounds 15a and 15b , 15c and 15d , 15f , 15g , 15h,i , 15n – q , and 15r were prepared following the literature procedures using allyl bromide and potassium carbonate in DMF (Scheme , method a) . N ‐Allylpyridinones 15h and 15i were successfully prepared in the same manner to avoid formation of O ‐allylated by‐products reported as a major problem in the application of a PTC approach .…”

Regioselective and Facile Synthesis of 7,9-Dialkyl-8-oxopurines from 7,9-Dialkyl-7,8-dihydropurines: Total Synthesis of Heteromines I and J

“…We succeeded in developing a high-yielding and regioselective preparation of 7-substituted halopurines, 24 and 7substituted adenines, guanines, and 6-mercaptopurines. 25 During the course of our studies, we observed that exposure of a solution of 7,8-dihydro-9H-purine 2a to air afforded a small amount (≤10%) of 8-oxopurine 3a as the product of spontaneous oxidation 26 (Scheme 1). However, to the best of our knowledge procedure for the preparation of halo-substituted 8-oxopurines, valuable intermediates in the synthesis of functionalized purines, based on oxidation of 7,8-dihydro-9H-purines has not been reported.…”