LAUSR

Purines are heterocyclic aromatic organic compounds consisting of two 5‐ and 6‐membered fused rings containing nitrogen. They are present in numerous compounds, including natural products, with potent biological activity. Purine analogs are used for the treatment of acute leukemias. Thiopurine derivatives are effective antiviral (acyclovir and ganciclovir) or antitumor agents such as vidarabine, among other clinical uses. Over the years, the purine nucleus has become one important pharmacophoric group. It is capable of interfering in the synthesis and function of enzymes and nucleic acids. It is also frequently used in the development of protein kinase inhibitors. Our research group has developed new routes to produce purine libraries. One of such routes is the one‐pot synthesis to obtain 6‐, 8‐, and 9‐substituted purines from 4‐alkylamino‐5‐amino‐6‐chloropirimidines, alcohols, and N,N‐dimethylamides. We also presented a new approach, to obtain trisubstituted purines. We were able to prepare a library of polysubstituted purines. Some compounds from this library were found to be specific inhibitors of the death‐associated protein kinase‐1. The leading compounds of this library are potent inducers of apoptosis in tumor lymphocytes and also reduce viability of trypanosomes. We herein report the unambiguous assignment of H and C of a subset of these new purine derivatives. Assignments were carried out in compounds 3 k and 3n which have, as substituents, phenyl and benzyl at Positions 6 and 8, respectively. We also characterize compound 3o, which has benzyl, phenyl, and phenethyl substituents at positions 6, 8, and 9, respectively. We therefore provide better knowledge of the molecular structure of our compounds, while obtaining further insight for future structure–activity studies and for improving the structural determination of other purine derivatives.