Synthesis of purines bearing functionalized C-substituents by the conjugate addition of nucleophiles to 6-vinylpurines and 6-ethynylpurines

Purines bearing diverse P-substituted ethyl or vinyl groups in position 6 were prepared by the conjugate addition of N-, O- and S-nucleophiles to 6-vinylpurines or 6-ethynylpurines. The scope of this methodology was systematically studied. The addition of amines, alcoholates and thiolates to 6-vinylpurines gave the corresponsing 6-(2-aminoethyl)-, 6-(2-alk-oxyethyl)- and 6-[2-(alkylsulfanyl)ethyl]purines. The addition of amines to 6-ethynylpurines gave 6-(2-aminovinyl)-purines, while the addition of alcoholates and thiolates gave 6-(2-dialkoxyethyl)- and 6-[2-bis(alkylsulfanyl)ethyl]purines. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).