Synthesis of 3-(2-deoxy-beta-D-ribofuranosyl)pyridin-2-one and 2-amino-6-(N,N-dimethylamino)-9-(2-deoxy-beta-D-ribofuranosyl)purine derivatives for an unnatural base pair

An unnatural base pair, 2-amino-6-(N,N-dimethylamino)purine (denoted x) and pyridin-2-one (denoted y), was designed to prove the structural requiremen ts for base pair formation involving shape complementarity. It was expected that y might satisfy the structural requirements for pairing with x, in wh ich the bulky 6-dimethylamino group may eliminate base pairing with the nat ural bases. As chemical or biological substrates for DNA synthesis, the pho sphoramidite of x and the 2'-deoxy-C3-ribonucleoside triphosphate of y (dyT P) were synthesized, and the incorporation experiment was demonstrated by u sing the Klenow fragment of Escherichia call DNA polymerase I. (C) 2000 Els evier Science Ltd. All rights reserved.