One-step synthesis of novel tricyclic isomeric azidonucleosides
摘要:
Several tricyclic azido-isonucleosides were formed in high yields by the treatment of pyrimidine isonucleosides with triphenylphosphine, tetrabromomethane, and sodium azide. The regioselective ring opening of these tricyclic azido-isonucleosides was also investigated. (c) 2006 Elsevier Ltd. All rights reserved.
Stereoselective synthesis of 4-deoxy-4-nucleobase-2,5-anhydro-l-mannitol derivatives
摘要:
2,5:3,4-Dianhydro-L-talofuranose dimethylacetal 7 was synthesized from D-glucose in 7 steps. A series of 4-deoxy-4-nucleobase-2,5-anhydro-L-mannitols 13-16 were synthesized regioselectively from 7 in good yields. 6-O-p-Tolylsulfonyl-2,5:3,4-dianhydro-L-talofuranose dimethylacetal 8 reacted with uracil or thymine to give the corresponding isonucleosides 17 and 19, but in the case of reaction of 8 with adenine, reformation of tetrahydrofuran ring took place, giving 4-(S)-adenyl-5-(R)-[1'-(R)-hydroxy-2',2'-dimethoxyl] ethyl-2,3-dihydrofuran 21 and 4-deoxy-4-adenyl-2,5:3,6-dianhydro-L-mannofuranose dimethylacetal 22. (C) 1997 Elsevier Science Ltd.
Novel oligonucleotide analogues built from isonucleosides were synthesized by the phosphoramidite approach on an automated DNA synthesizer. The phosphoramidite building blocks were synthesized by phosphitylation of the corresponding protected isonucleosides. The oligonucleotide analogues C - G containing the isonucleoside 1-3 were studied with respect to their hybridization properties and enzymatic stability. The oligomers bearing an isonucleoside at the end of the strands all proved stable towards snake-venom phosphodiesterase, but only the oligomers D-G exhibit acceptable duplex stability when hybridized with complementary d(A(14)).