Covalent Analogues of DNA Base-Pairs and Triplets IV. Synthesis of Trisubstituted Benzenes Bearing Purine and/or Pyrimidine Rings by Cyclotrimerization of 6-Ethynylpurines and/or 5-Ethynyl-1,3-dimethyluracil
Covalent Analogues of DNA Base-Pairs and Triplets IV. Synthesis of Trisubstituted Benzenes Bearing Purine and/or Pyrimidine Rings by Cyclotrimerization of 6-Ethynylpurines and/or 5-Ethynyl-1,3-dimethyluracil
Cyclotrimerization of 6-ethynylpurines. Synthesis of 1,2,4- and 1,3,5-tris(purin-6-yl)benzenes as novel Hoogsteen-triplet analogues
作者:Michal Hocek、Irena G Stará、Ivo Starý、Hana Dvořáková
DOI:10.1016/s0040-4039(00)01989-4
日期:2001.1
Cyclotrimerization reactions of the 9-protected 6-ethynylpurines 4a,b in the presence of various transition metal catalysts were studied. The best results were obtained with Ni(COD)2 or Ni(COD)2/PPh3 to obtain the 1,2,4- and 1,3,5-tris(purin-6-yl)benzenes 5a,b and 6a,b in moderate to good yields (in a 4:1 to 10:1 ratio). This method is suitable for the practical synthesis of the unsymmetrical 1,2,